# DVD burners that rock for diodes.



## Kenom

The purpose of this thread is to educate and let others know of our own success. It is my hope for this to one day become a sticky and people looking to make thier own DVD burner lasers can come to this list of DVD burners and choose from the list which burner to get to make thier own Laser.

Essentially what you do is if you have torn into a DVD burner for the specific purpose of harvesting a DVD Laser diode, post what your findings were. 1. What was the brand? 2. What was the model #? 3. Was the diode open or closed? 4. What kind of power did you get out of it?

I will start things off with my own experience in this and my own findings thus far.

1. Plextor
2. Px-708a
3. Diode was closed
4. Output power in the range of 100mw.


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## Corona

By "open or closed" do you mean if the diode package has a window (glass over output aperture) or not (as many cheap reds have none for cost reasons)?

I have a burner coming for a project and will participate, though I have no power meter...


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## KrisP

1. Pioneer
2. DVRA07
3. Closed
4. Don't know

1. Pioneer
2. DVRA09
3. Closed
4. Don't know

1. Pioneer
2. DVR112
3. Open
4. Don't know


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## Kenom

Corona by open I mean that there is no glass covering the output aperature. Closed has glass.

Thanks for your input Krisp.


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## Corona

1. LG
2. GSA-H42N
3. Uncovered (open). 
4. Melts through a trash bag. Makes cigar butts smoke (blackened tobacco). Pops balloons with black marker spot. Won't easily light a match, but I'll be trying again.

Operating at 150mA in Elly-based assembly, 10 ohm 1/2 watt resistor. Assembly has variable focus and Aixiz brass module, plastic aspheric lens.

I've run it for in excess of 5 minutes at a time and it doesn't even feel warm. The Elly body does a great job of heatsinking the laser module!

The size / length of the semiconductor laser in the diode is _way cool_; it's easily 3mm long. One problem this introduces in the Elly (as I make them) is it places the output mirror facet a bit closer to the collimating lens, preventing point-blank focus (the brass collar / lens has to be unscrewed too far - all the way off if you're not careful). It will safely (?) achieve about a 6 inch (15cm) focal distance to a sharp spot, and adjusts out to a fairly well collimated beam for general "oh wow" duty and beam shots.

Against my ~25mW greenie, it appears to have about equal luminosity both to the eye and digital camera. It's a whole lotta red!


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## Kenom

Thanks for the input. Doesn't anyone have any experience with which DVD burners netted you a good diode?


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## Aseras

NEC good, 150-180mw

LG good, but open can ( when i say open can I mean bare diode no metal at all not just a missing window ) 200mw+, but fragile as hell, every one has died while i tried to make it into something.


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## Gazoo

Hello Aseras,
Do you happen to know the model number of the NEC?


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## Kenom

I just got done tearing into a Sony DW-D26A Bought the drive as-is on ebay and was not functioning for reading or writing so I figured what the hay! Lo-and-behold closed cans. Pretty good power.

So here it is.

1.Sony
2.DW-D26A
3. Closed diode
4 unknown output.


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## Levitra

Hi, my laser is

1. Benq
2. Dw1620
3. 5.6 mm with glass (closed)
4. Don´t know output power

I use it at 150 mA and Vd=2.59 volts (389 mW input power) with a collimator from a laser copier. So output power must be near 100mW.
None heat problem and very low divergence.


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## Kenom

another report of a good dvd rewritable drive

1. Memorex 
2. MRX-525G 
3. closed cans
4. output power unknown


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## Kenom

and another I tore into the other day.

1. HP
2. ZD8000 notebook drive.
3. Red was closed can IR open can
4. Unknown output power.


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## Gazoo

1. Benq
2. Dw1625
3. 5.6 mm with glass (closed)
4. Greater than 100mw

I am guessing on output power, but I think it's close when driven with greater than 200ma. Currently I am driving the diode with around 240ma. It will light a match with a light gray head as long as the focus is perfect. I am using a Meredith module with a glass lens. It does start to heat up if left on for longer than a minute. Anything less and it stays cool.


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## Kenom

1. LG
2. GSA-H42L
3. Closed can. 
4. Output Unknown.

It must be noted that this particular model had a very large heatsink that the red diode is mounted into. It is very difficult to remove and takes lots of patience.


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## Bernhard

1. Sony 
2. DRU-700A
3. Closed can for both IR and Red.
4. Unknown Output


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## Bernhard

1. Lite-On
2. LH-20A1P
3. Open can for both IR and Red
4. Not Known


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## VaThInK

1. Sony
2. DRU-800A
3. Open diode
4. 342mW peak @ 650mA with good heatsink

1. Pioneer
2. 112D
3. Open diode
4. 345mW peak @ 650mA with good heatsink

I assume most of the red diodes used in 18x DVD burners are the same. I've tried Samsung, LG and Lite-On 18x burners (forgot the model) as well with similar results to the above.

PS: Just keep in mind that these diodes get extremely hot real quick when being fed at 650mA without proper cooling (gets to 50C within 2 minutes with ambient room temp at 18C). So an active cooling such as fan assisted heatsink or peltier cooler is very recommended for longer duty cycle.

Cheers.


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## Kenom

those are some pretty impressive output power levels. Can you post pictures of what your open can's look like. I've got a few open cans that I've seen but for some reason I am thinking they are completely different that what others are getting. I will post a pic of mine!




Shot at 2007-07-03




Shot at 2007-07-03

I find it odd I keep finding diode's that are rectangular instead of circular. This particular diode is IR.


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## VaThInK

Here you go mate. From all of the DVD burners I have dissected above, I always ended up with this type of diodes. They look "prettier" than the closed one I reckon . Very sexy :naughty:.

PS: This particular one have been through a lot as you can see from the scars on its body in the picture. However, this one is still putting out 342mW of red goodness without a hitch :twothumbs. I found them to be quite durable and I don't know why you are keep on breaking yours Aseras. Maybe you need to be more gentle in handling these beast .

Kenom: I've only come across with this type of diode once. It was the IR diode in a SCSI 12x Pioneer CD-ROM drive. Exactly like yours, the weird looking ones.





Shot at 2007-07-04


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## Gazoo

Hello VaThInK,

Hmmm they do look somewhat sexy. That's a lot of power coming out of that diode. I wonder if the diode has a tendency to stay cooler because it is open, not sealed like the ones most of us are familiar with. I definitely must try one of these. A quick search on e-bay revealed both of the drives you mentioned can be found for less than $40.00 including shipping. Maybe soon I can get one. The one I pulled from my Benq is still going strong.....


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## Bimmerboy

VaThInk - Cool, my first look inside a can! Wait... that didn't sound right. :green:

Dammit, Jim... I'm a flashaholic, not a proctologist!

BTW... you're sure those diodes are putting out almost 350mW? I'd have thought even attempting it would be _instant death_ for any 5.6mm package... even the 20X'ers.


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## KrisP

1. Pioneer
2. DVR111
3. Closed
4. Don't know


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## Kenom

WOW! 340mw! I would be freaking goin crazy. I donno if I can work with anyhting quite that powerful. I would have to learn a bit more before going so far as to cool that baby. So far I'm sure the main reason I've fried the one's I'm playing with are because of insufficient cooling. I'd kill it almost instantly trying to mess with that cause I don't have the means to cool it properly. You will have to show me a picture of what you mean by active cooling and how you accomplished it. I know what peltiers are and havn't got any but could.

Thanks much for the Picture. It is very sexy.

Most of my weird diodes have come from laptop drives. they must only make them in those. the first one was in a HP laptop dvd rw and the other was in a sony. BOTH IR. Now I need to devise a way to make it work as a laser. Odd shaped chamber with circular optics but rectangular mounting.


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## Aseras

That's the open can diodes I was saying were in the LG burners. all of them are way powerful but also very very fragile.

you touch the wire going to the diode and it dies.


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## VaThInK

Behold, is this freaky or what ? I just hit the 400mW mark on the dot ! And it was going steady down to 391mW. I rigged up this quick and dirty setup to proof to Bimmerboy that I did manage to get 345mW reading previously without peltier or active cooling but only using the laser diode housing from Aixiz on eBay. It turned out to be a bomb when I set the current to 700mA coupled with peltier cooler :twothumbs. By the way, thanks to SenKat for recommending LPM-1 to me. Just received it a few weeks back and now I can measure my findings. Such a great meter. Thanks again SenKat!
* 
NOTE: If you decided to try to feed your LDs at around 600mA, please keep in mind that the duty cycle should be kept at around a minute or so maximum or you'll regret it later .*

I've tried to find its maximum current in the past and based on the results that I get so far, I can safely conclude that this kind of diodes can withstand current from 750mA up to 800mA maximum while keeping it's temperature at around 30C. Pushing the current beyond 800mA then you're only asking for trouble, as they will only light up for hours, minutes, or even seconds regardless its temperature! This varies from LDs to LDs. I actually blew 2 of them when I pushed one to 950mA with its temperature reading at 4C and another one at 850mA. They worked for about an hour and then , they turned into weird looking LEDs .

And here's the picture that you've been waiting for :twothumbs.





Shot with Canon DIGITAL IXUS 60 at 2007-07-05

All in all, I reckon this is the best laser ever! 400mW red lasers at around $35 each, nothing beats its value. Nothing comes even close! Too bad it's red.

Kenom: What I meant by active cooling is by using a heatsink coupled with a fan to cools it down. CPU coolers is one example or you could rig one up from common parts that you can easily get from your local electronic shops. I guess it's best to use old CPU coolers such as from Pentium I, II, III or Athlon K7 CPUs. Newer CPU heasinks are harder to adapt but it's possible too if you're willing to do more work. Personally, I haven't made mine yet, but I have been thinking of doing so lately. Too bad I haven't got enough free time to turn this into reality thanks to my job. One day I will though, one day I will. Anyway, one way to achieve this by drilling a hole on the center of the heatsink (or wherever you see fit) and then flush the LD housing halfway into it and fix it in place by using thermal epoxy or anything that conduct heat and you're done.

PS: Sorry if the picture is too big. Let me know and I'll fix it.

Cheers.


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## Kenom

what is that pad sitting on top of the peltier?

I'm curious if that is all You have for active cooling I'm sure some kind of heatsink wrapped around the Aixiz module (it would have to be fairly large with a fan) would accomplish the same thing. Now I'm no expert and have never actually played with a peltier so donno how cold they get, but a good sized heatsink with air flowing over it should work.


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## VaThInK

Kenom said:


> what is that pad sitting on top of the peltier?



That huge block is a heatsink designed to be used for audio amplifier. It was not cooled down by a fan. That's why I use a big heatsink. As I said, I did that setup in 10 minutes just to prove my claim. So what I did was I took out my peltier cooler (it was already attached like that to the heatsink as you can see in the picture as I can't be bothered taking it apart when I finished my old project). Then I put a wet tissue in between the LD housing and the peltier to improve the heat transfer and that's about it.



Kenom said:


> I'm curious if that is all You have for active cooling I'm sure some kind of heatsink wrapped around the Aixiz module (it would have to be fairly large with a fan) would accomplish the same thing. Now I'm no expert and have never actually played with a peltier so donno how cold they get, but a good sized heatsink with air flowing over it should work.



Yep, you're right. As I said, a small Pentium III coolers (60mm x 60mm heatsink with a suitable fan) would do the job quite well. Remember though, I've never tried it, but I think it is sufficient. I did mine using peltier because it is easier for me. I already got it set up and ready to run and I don't have a heatsink built up ready for testing. I have heaps of them lying around in my storage though. Something like 30+ heatsink fan modules but I just don't have enough free time to do it :thumbsdow.

Peltier can go as low as -20C without any load acting on the cold side, so it will freeze water no problem. When heat is applied to the cold side, it will drop significantly of course. The hot side is very hot, hence the huge heatsink. This particular ones have a cooling/heating power of 240W.

Hope I have answered your questions.

PS: When this laser is not collimated (I took out the collimating lens), I can feel the heat when I shone it to my hand. This is when the beam diameter measured at around 5cm! I am so amazed! Now this is dangerous stuff alright. *Please, anyone that are going to attempt this, be very very very careful with it. This thing can melt a thick plastic. Always consider safety first. Better safe than sorry.*

Cheers.


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## Kenom

ahhhh it was the wet tissue that I was referring to. I was like huh? he's got a cloth there. wtf? LOL considering that your peltier is getting that cold I am not quite sure that a heatsink and a fan will be sufficient then. You physically putting something that is very cold right onto the module and I don't think that a simple heatsink and fan could accomplish this. You would have to buy one of those water cooled assemblies. (wish I knew where to get those! (suggestions anyone))

Here is a heatsink idea I was looking at but instead of having just fins protruding from one area have it circular with a solid base that is hollow for the module.
http://www.zalman.co.kr/usa/product/view_slide.asp?idx=33&idm=1


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## Gazoo

I have been looking into this. Peltier's are fairly inexpensive. I have thought about mounting one to a cpu fan and head sink arrangement using arctic thermal paste. But I am not sure how I would mount the module to the peltier.

Also there is the problem of condensation that develops but I don't know how bad it would be since we know we do not want to run it for long duty cycles. 
This could turn into an interesting project. I saw some small peltiers on e-bay that would be good. I know they draw a lot of power so portability might be a problem unless using a lead acid battery. Perhaps all of this could be installed in one of those big lead acid flashlights. One would have to cut slots or holes for ventilating, but I think it could be done.

I have a peltier cooler. It will run for about an hour on a 7 amp 12 volt battery, just to give an idea of the power requirements.


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## Kenom

I had some heatsinks made up to fit inside my Mini Dorcy mod so that it would wick the heat from the Aixiz module to the head of the Dorcy and act as a heatsink. 
Now I'm working on getting something like this but bigger with fins that go from the bottom of the spacer to the top. Maybe I can just epoxy some fins onto the spacers!





By kenkassdy at 2007-07-05



You can also check out the heatsinks that were made by Tallaxo on LPF here
http://www.laserpointerforums.com/forums/YaBB.pl?num=1181994764 

He really did a bang up job on those heatsinks.


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## VaThInK

Kenom said:


> ahhhh it was the wet tissue that I was referring to. I was like huh? he's got a cloth there. wtf? LOL considering that your peltier is getting that cold I am not quite sure that a heatsink and a fan will be sufficient then. You physically putting something that is very cold right onto the module and I don't think that a simple heatsink and fan could accomplish this. You would have to buy one of those water cooled assemblies. (wish I knew where to get those! (suggestions anyone))



, I should've read your question more carefully. Anyway, don't be let down by the cooling power figure of the peltier. The peltier wasn't cooling the LD efficiently due to the poor heat transfer. I ended up getting about 25C on the LD housing. This is kind of intentional. However, I really believe simple CPU heatsink coolers will to this job no problem as the heat generated from this diode is nothing compared to Pentium CPUs! Do you know how hot these CPUs get without cooling? You can burn your finger touching them while running without cooler. You do know that Hercules 400mW green laser is cooled down by a simple heatsink fan method, right? And it uses 2.5W IR diode inside! So this proves that simple heatsink fan assembly is sufficient. As long as it's capable of dissipating heat efficiently.



Kenom said:


> You can also check out the heatsinks that were made by Tallaxo on LPF here
> http://www.laserpointerforums.com/fo...num=1181994764



They look excellent! I wish I have the luxury of lathe as well. Very nice indeed. Would fit Aixiz housing perfectly I reckon. It would work hell of a lot better with longer fins though (better heat dissipation).

Gazoo: If you're thinking of building a lab unit. Just use a spare PC power supply. It works like a charm. I'm powering my LD from the 5V rail with just using a suitable resistor in series. The diode only gets 2.2V in the end so no problem. The resistor will eats the rest.


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## Gazoo

VaThInK said:


> Gazoo: If you're thinking of building a lab unit. Just use a spare PC power supply. It works like a charm. I'm powering my LD from the 5V rail with just using a suitable resistor in series. The diode only gets 2.2V in the end so no problem. The resistor will eats the rest.



I just thought of something else. The module I am using I ordered from meredith. They make a small brass square heatsink for the module. It would be much easier to mount this to a cpu cooler. 

As far a power you have a good idea. It could also be used to power a peltier. 

I really am impressed with the open can diode just by looking at the picture. I want one to experiment with


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## Bimmerboy

Va - 400mW peak from the Andover? Cans off to ya'! What burner did it come from?

Aseras - Touching bond wires again? Perv! :nana: J/K!

Granted, I haven't been reading every single datasheet on all the latest stuff, but am amazed at what you guys are saying about some of the open cans. What would be the differences between those, and the 16/18X Rohm and/or Opnext closed cans? Surely it's not the window that accounts for that much loss?

Just had a 16X Rohm die on me the other day after sustaining only a few months use @ 300mA with light use and VERY conservative duty cycles.

Kenom - Nice looking little sinks!


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## Comidt

Hi
Sorry to be a bit off-topic, but I cannot find the post to do with the Andover Meter. How much do they cost and how accurate are they. Please help me, I'm wanting to get big into lasers and am looking to see what kind of power meters there are.
VaThink, that must be pretty cool to have a Laser that powerful. Which one of the burners did it come from?

Thanks
Jonno


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## VaThInK

Comidt: If you're interested in LPM-1, just get in contact with Tony_and_holo. He's a member at CPF as well. If I remember correctly, I think he's selling the basic unit for $199.00 and claims that it has an accuracy of at least 5%. I saw a thread in here doing a comparison of the unit with a commercial ones and it's actually within 2% (or 1%, I can't remember exactly). Personally I must say that it's the best meter for the price.

To all of you who are curious about the origin of the LD used in the picture, this particular ones came from Pioneer 112D 18x DVD burner. I also recommend this drive as it's very easy to pull both IR and red LDs apart.

In regards to 16x DVD burners, I have tried the red LD from a Sony DRU-720A 16x DVD burner (my old drive) before I get my hands on newer 18x DVD burners and I have to say that the red LDs used on both model (Pioneer 112D) are exactly the same by looking at the results that I get. Never tried 20x DVD burners yet though, but I have a feeling that they use the same red LDs. I hope I'm wrong. I want more mW please :naughty:.

Bimmerboy: "...16/18X Rohm and/or Opnext..." - You've lost me there mate .

Gazoo: Sounds pretty good. I will check out Meredith website and might get the heatsink from them as well. It will be a lot easier to make a cooler and will look a lot better too. I just hope it won't cost an arm and leg. Anyway, that's what I use to power my setup. I could run a few of them off the PSU actually if I wanted to. The cheapest high powered laser setup I think. Hehehe.


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## Comidt

Cool Thanks Very Much VaThinK.
I heard that they weren't that accurate with green colours, is this true? apparently thay had to get glass filters as well, because the alsers melted the plastic one...
Thanks
I will be looking into getting that DVD Writer sometime.
$30 off newegg.
Jonno


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## Gazoo

Comidt said:


> Cool Thanks Very Much VaThinK.
> I heard that they weren't that accurate with green colours, is this true? apparently thay had to get glass filters as well, because the alsers melted the plastic one...
> Thanks
> I will be looking into getting that DVD Writer sometime.
> $30 off newegg.
> Jonno



Gotta love newegg....lol. As for the LPM-1, I am curious where you heard they are not that accurate with green colors. I bought SenKat's LPM-1 but I am still waiting for it. He had it compared to a commercial meter and it was very accurate, but I don't know what colors they used. Then he sent it to Andover for recalibration with the glass lens. I am looking forward to it. I think two of the best features are you can plot laser power by connecting it to the serial port of a computer, and according to the instructions it is software upgradeable.


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## Gazoo

VaThInK said:


> Gazoo: Sounds pretty good. I will check out Meredith website and might get the heatsink from them as well. It will be a lot easier to make a cooler and will look a lot better too. I just hope it won't cost an arm and leg. Anyway, that's what I use to power my setup. I could run a few of them off the PSU actually if I wanted to. The cheapest high powered laser setup I think. Hehehe.



Hi VA,
I don't know if you have a meredith module but they are pricey. However I have been very happy with mine the more I use it. I mounted it in the reflector in one of those stand up flashlights that comes with a drill kit. The reflector is metal so this provides for additional heat sinking. 

The battery pack for the drill kit went bad so I tore the batteries out and installed a 4 cell eneloop pack. I threw out the wall wart that came with the charger, and use a universal charger to charge the batteries. Whenever I get a new battery pack for the drill, I can slip it into the cradle and charge it, and can slip in the revised pack I made and charge it too.

The beam is sweet. I am running it 240ma, so I can assume I am getting a little over 100mw output. It will easily light a sharpied match from about 2 feet away. I could probably push it to 300mw but I want this to last awhile.

Last night I pointed it at the clouds and the dot was very easy to see. It was neat as it is the first time I have done this.

FYI, I have the meredith module with the glass lens. As far as I can tell from their website, the one with the acrylic lens produces a tighter beam. The brass cube they have for mounting the module in is small, but looks to be perfect for any application to a larger heat sink or TEC.


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## Comidt

Gazoo said:


> Gotta love newegg....lol. As for the LPM-1, I am curious where you heard they are not that accurate with green colors. I bought SenKat's LPM-1 but I am still waiting for it. He had it compared to a commercial meter and it was very accurate, but I don't know what colors they used. Then he sent it to Andover for recalibration with the glass lens. I am looking forward to it. I think two of the best features are you can plot laser power by connecting it to the serial port of a computer, and according to the instructions it is software upgradeable.


I suppose I didn't see that they were unaccurate, just that they had plastic lenses, and there were problems with them so they got glass filters and were calibrated or something like that??
So do they do peak, average, etc.
(Sorry kenom for messing up your thread!)
Jonno


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## Gazoo

Comidt said:


> I suppose I didn't see that they were unaccurate, just that they had plastic lenses, and there were problems with them so they got glass filters and were calibrated or something like that??
> So do they do peak, average, etc.
> (Sorry kenom for messing up your thread!)
> Jonno



Comidt, yes, the only problem I am aware of with the meter was on account of the use of a plastic filter. He now uses glass filters. The original thread for the group buy follows:

http://www.cpfmarketplace.com/mp/showthread.php?t=153251


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## Comidt

Where can I get one of those meters now?


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## Kenom

I'm sure if you PM that Dr lava he will sell you one.


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## Kenom

I hope that I can find some diode's as good as the one SenKat is selling. He's got some 16X dvd diode's from sony that are up to 250mw's. I plan on getting me a few of those and making some excellent red burners from them. The datasheet on these diodes is here. Might wanna check em out he's got them for sale in the Market place.


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## Gazoo

Kenom said:


> I hope that I can find some diode's as good as the one SenKat is selling. He's got some 20X dvd diode's from sony that are up to 250mw's. I plan on getting me a few of those and making some excellent red burners from them. The datasheet on these diodes is here. Might wanna check em out he's got them for sale in the Market place.



I believe the ones SenKat has are for 16X dvd's. Still, it is a good deal and I may get a couple. However I am mainly interested in obtaining an open can diode.


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## Kenom

You are correct and I've edited my original post


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## Bimmerboy

Just to clarify about the Sony 16X diodes, they're 250mW only when pulsed, which won't give any practical advantage in terms of brightness over their 80mW continuous rating. Of course they can overdriven to within reason. 140 - 150mW CW is probably a safe enough range for at least some reliability, while giving good power. I was driving my 16X Rohm to somewhere around 170mW (306mA current going through it), and it just died the other day after a minimum of use.

It was fun while it lasted. Thing was pretty damn strong.


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## Kenom

yeah, I'd imagine that putting that much current into a diode woudl kill it. I don't intend to overdrive the diode all that much I'm wanting to get somewhere in the vascinity of 150mw ~ 200mw. I do have some plugs of aluminum that I'm going to be using on these to increase the heat transfer.


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## Comidt

So what can I easonably expect from these diodes if I power it from a Dorcy??


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## Bimmerboy

Bimmerboy said:


> 140 - 150mW CW is probably a safe enough range for at least some reliability, while giving good power. I was driving my 16X Rohm to somewhere around 170mW (306mA current going through it), and it just died the other day after a minimum of use.





Kenom said:


> yeah, I'd imagine that putting that much current into a diode woudl kill it. I don't intend to overdrive the diode all that much I'm wanting to get somewhere in the vascinity of 150mw ~ 200mw.



:thinking: LOL :nana:

Couldn't resist the tease, man. However, do read my post again.

BTW, in most cases with a DVD laser, heatsinking won't be of much practical value. At rated drive levels, the mass of the module/lens holder alone is enough sinking for at least a couple or a few minutes of constant on... and you won't even feel the module get warm. And when overdriven, damage happens to the mirrored facets of the resonant cavity, which a heatsink cannot prevent. Thus the reason for short duty cycles. In this case again, you'll never even feel the module get warm, much less a surrounding heatsink.

Comidt - Which Dorcy? It's been tough to keep up on all things photonic these days.


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## Kenom

Bimmerboy said:


> BTW, in most cases with a DVD laser, heatsinking won't be of much practical value. At rated drive levels, the mass of the module/lens holder alone is enough sinking for at least a couple or a few minutes of constant on... and you won't even feel the module get warm. And when overdriven, damage happens to the mirrored facets of the resonant cavity, which a heatsink cannot prevent. Thus the reason for short duty cycles. In this case again, you'll never even feel the module get warm, much less a surrounding heatsink.
> quote]
> 
> 
> I don't have the necessary information at my disposal but I would tend to disagree that sufficient heatsinking can and will be of practical value. If that were the case Lab lasers rated at much higher than a DVD laser is capable wouldn't need TEC's or other means of active cooling. This laser is rated at 250mw pulsed so one would think the resonant cavity would be able to tolerate CW at that rated output with sufficient cooling.


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## Kenom

if you run it in the mini dorcy with a capacitor and a resistor to drop voltage down a bit you can probably get somewhere in the neighborhood of 150-200mw of red. I do want to note that he's only got about 40 left of these babies. They are RedHOT. LOL. sure beats buying a dead dvd burner and tearing it apart. for the same cost as one dvd burner I can get 3-5 of these diodes.


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## Comidt

Thanks Kenom, that's the one i was thinking of.


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## Kenom

well, we now have an official deadline for anyone getting on the order of diodes. 9am CST is hte deadline for this first order.


----------



## Gazoo

Yeah, it's too good to pass so I ordered 5. But I still want an open can diode...lol.


----------



## Comidt

Kenom said:


> well, we now have an official deadline for anyone getting on the order of diodes. 9am CST is hte deadline for this first order.


You almost gave me a heart attack when I read that.
It's the 11th of July at 9am CST. i just bought 4 from him last night, so I can't for this. My first burning laser...
Jonno


----------



## Kenom

hehe sorry! I was only referring to the one's he has for sale. nothing else. My bad for not putting the date on there!


----------



## Gazoo

1. Lite-On
2. LH-20A1H-185
3. Open can
4. Not sure of power output

Like VaThInK said these seem to heat up pretty fast. But they are neat. I have it mounted in a flashlight and am using a Meredith module. But I am using the lens out of the smaller Aixiz module and it fits perfectly in the Meredith module. The reason I like the Aixiz lens better is it produces a beam that is smaller in diameter, and is much better for burning.

I am using an old driver board that came from another module and the current is regulated at 240ma going to the diode. This driver board is non adjustable. Even with the bigger Meredith module, I would not use a higher current without providing more cooling.

I have more experimenting to do. I am very tempted to get another Meredith module with the acrylic lens and a couple of the heat sink blocks.


----------



## FloggedSynapse

Bimmerboy said:


> BTW, in most cases with a DVD laser, heatsinking won't be of much practical value. At rated drive levels, the mass of the module/lens holder alone is enough sinking for at least a couple or a few minutes of constant on... and you won't even feel the module get warm. And when overdriven, damage happens to the mirrored facets of the resonant cavity, which a heatsink cannot prevent. Thus the reason for short duty cycles. In this case again, you'll never even feel the module get warm, much less a surrounding heatsink.



I think it's loco to state that heatsinking is of no value. You might have gotten significantly more life out of that diode that popped after one day if you'd properly heatsinked it, for example.

Diode lifetime often declines exponentially with increasing temperature. Until recently most LDs have been more sensitive to heat than processors - most parts have their rated life @ 20C, even if they can tolerate much higher temps. Even if only used in short bursts a well heatsinked part will be cooler (at all times) than a comparable part that is not.


----------



## FloggedSynapse

Kenom said:


> I hope that I can find some diode's as good as the one SenKat is selling. He's got some 16X dvd diode's from sony that are up to 250mw's. I plan on getting me a few of those and making some excellent red burners from them. The datasheet on these diodes is here. Might wanna check em out he's got them for sale in the Market place.



I'm ordering a couple of these diodes. Perhaps another 2-4 in a week or two if there are still any left.

OK, so what are these good for CW?? Looking at the specs for the part..
http://www.sony.net/Products/SC-HP/cx_news/vol37/pdf/sld1236vl.pdf
they are showing an average current consumption (@ 2.5 volts) of 130 mA to get 80 mW out of the diode. I'm assuming these can be safely overdriven to 100-200 mW?

What are people using for a power supply? I was thinking of running mine off batteries and just using a resistor to regulate the current, along with a capacitor ("soft start" lol). I've already got a meredith 'ldc1' diode housing/collimator (though i'll have to order the 5.6 to 9 mm adapter) and mounting block (as a heatsink). 

I've had good luck with these meredith parts on my first batch of laser flashlights. But these are 15-20 mW (635 nm) diodes that only draw 70-100 mA of current. I'm worried I might need a better heatsink for use with the higher power LDs.

Here are some pics of my first batch of laser-pointer-flashlights. Still going after at least a 100 hours of use (15-25 mW @ 635 nm).

pic of laser flashlights (sdl-7501 diode - meredith housing/collimator - ns102 apc power supply)
http://www.fractalfreak.com/wx/bigred2.jpg

beam shot in dim room
http://www.fractalfreak.com/wx/bigred.jpg

bathroom ceiling bounce (yeah it's that orange, this diode is ~630 nm)
http://www.fractalfreak.com/wx/red_3.jpg

green + red mixing pictures - 5 mW green + 20+ mW red
http://www.fractalfreak.com/wx/red_7.jpg
http://www.fractalfreak.com/wx/red_6.jpg

shining laser into suspended cotton ball
http://www.fractalfreak.com/wx/redlaser2.jpg


----------



## Gazoo

I don't know what they can be safely overdriven at as far as power output. But I believe the can be safely driven with 250mw input power. I have ordered 5 so I will be able to find out. I am think about ordering 1 or 2 of the following:

http://www.dimensionengineering.com/AnyVoltMicro.htm

I know they are expensive, but they are not nearly as expensive as the driver board Meredith has, and I believe they will do basically the same thing, perhaps better. Thoughts...


----------



## FloggedSynapse

Gazoo said:


> I don't know what they can be safely overdriven at as far as power output. But I believe the can be safely driven with 250mw input power. I have ordered 5 so I will be able to find out. I am think about ordering 1 or 2 of the following:
> 
> http://www.dimensionengineering.com/AnyVoltMicro.htm
> 
> I know they are expensive, but they are not nearly as expensive as the driver board Meredith has, and I believe they will do basically the same thing, perhaps better. Thoughts...



I dunno, but I think it's a sketchy idea. LDs have unusual drive requirements. It's important the supply be free of any transients, especially when first powering up. A spike that an LED would never notice can be enough to fry a LD. For a high power LD all you really need is a constant current supply, ideally with a trim pot to adjust the current to the diode. The Meredith supply is waaay overpriced I think, however all you'd need is a resistor to limit voltage/current and some caps to provide a 'soft start' - all this assumes you're using batteries.


----------



## Bimmerboy

FloggedSynapse said:


> I think it's loco to state that heatsinking is of no value. You might have gotten significantly more life out of that diode that popped after one day if you'd properly heatsinked it, for example.



Actually, I didn't say that, as such a statement would not have any context. Then I'd be loco. What I did say was very contextual, and I believe would apply to the _primary_ use that _most_ DVD lasers see... as an overdriven pointer, not kept on for very long periods. In such cases, I submit that a heatsink will be of very little or no use, because the facet damage will happen before the first calorie of heat makes it out of the diode/lens module. 

For example, I was driving my 16X diode at more than double the rated current, possibly pushing out as much as 170mW of *non*-colored match lighting fun. At times, it could be on for over a minute, and guess what... the module stayed cool as a cucumber. No change in temperature whatsoever. I wonder how much longer it could go with no detectable heat if it were run at, say, only 200mA.

A heatsink would not have allowed my diode to live one minute longer. What killed it was accumulated damage from massive overdrive, until one day it flashed just from the spike of turning it on (BTW, it was built in late Feb... definitely more than one day). Now if one were to use their home made pointer like a long duty cycle lab laser, heatsinking certainly makes sense, as does more reasonable drive levels.

Edit: Forgot to mention that the diode was slid into the module with a little AS5, and then a little was put on the threads before screwing on the back end. It's likely that heat transfer was optimal.

And a few questions... On average, how long are people leaving their reddies on for? How much time until you can feel some heat? What do ya'll do with your lasers on that long?... lol.


----------



## VaThInK

Bimmerboy said:


> Actually, I didn't say that, as such a statement would not have any context. Then I'd be loco. What I did say was very contextual, and I believe would apply to the _primary_ use that _most_ DVD lasers see... as an overdriven pointer, not kept on for very long periods. In such cases, I submit that a heatsink will be of very little or no use, because the facet damage will happen before the first calorie of heat makes it out of the diode/lens module.
> 
> For example, I was driving my 16X diode at more than double the rated current, possibly pushing out as much as 170mW of *non*-colored match lighting fun. At times, it could be on for over a minute, and guess what... the module stayed cool as a cucumber. No change in temperature whatsoever. I wonder how much longer it could go with no detectable heat if it were run at, say, only 200mA.
> 
> A heatsink would not have allowed my diode to live one minute longer. What killed it was accumulated damage from massive overdrive, until one day it flashed just from the spike of turning it on (BTW, it was built in late Feb... definitely more than one day). Now if one were to use their home made pointer like a long duty cycle lab laser, heatsinking certainly makes sense, as does more reasonable drive levels.
> 
> Edit: Forgot to mention that the diode was slid into the module with a little AS5, and then a little was put on the threads before screwing on the back end. It's likely that heat transfer was optimal.
> 
> And a few questions... On average, how long are people leaving their reddies on for? How much time until you can feel some heat? What do ya'll do with your lasers on that long?... lol.



Your statement is only partially correct in my opinion. Applying a way of dissipating heat generated from semiconductor will always help prolong its lifetime. However it also depends on other factors as well. You're right though when you said that if the LD is driven too far, some kind of damage would've been occurring before the heat could even get away. But trust me cooling will also help. By how much you ask? Depends on how hard you push it. Personally without a means of extra cooling, I would never be able to push my LD beyond 700mA (I've tried up to 1000mA). Without extra cooling, one of my LD went  instantly at 600mA. With extra cooling I have tried it running for a couple of hours at 750mA no problem so far. Don't get me wrong, this will surely shorten the life of my LD by a great amount, but properly heatsinking them helps to reach the impossible otherwise.

Think about when people OC their PC. eg: Doing volt mod. Why they even bother changing their cooling system? Simple, trying to release the excess heat generated when OCing to help prolong their system, which will make it more stable. Without better cooling, their system would die hell of a lot quicker. So it does matter. Every component have their desired working temperature. When this is ignored, expect for the worst .

To answer your question, sometimes I left my reddies for about an hour. Why? Laser show of course. Without proper cooling my reddies would reach ~45C in 5 minutes (at 600mA) and degrade like there's no tomorrow :mecry:. With just a passive cooling, it's still running strong to date ! Might last longer if I add a small fan on top of it I reckon.

I hope I'm making sense to you :candle:.


----------



## Bimmerboy

VaThink - The earnest response is appreciated, but what exactly did I say that was only partially correct? I would also ask you to clarify some statements in your last post... not to be combative, but so people don't get the wrong ideas, and start blowing their diodes.

When a LD is overdriven hard, what happens to the optical cavity occurs regardless of heatsinking, even TEC'ing. If one wanted to really try to prevent facet hotspots, and therefore, damage, you'd likely need to bathe it in something much colder than a TEC... liquid nitrogen for example.

When using more reasonable drive levels, you can long-duty cycle your laser with good heatsinking. A little overdrive won't be a problem. Eventually, the module will warm, and the sink will keep things stable. But again, much different story with hard overdrive... which brings me to the next point.

600mA? 750mA!? 1 Amp!?! Now as far as I can tell, a number of folks "in the know" (who I've been following the last few months) are wary of even short term testing an 18X diode at over 350mA. These guys don't host amateur night, so I tend to give them a little credence. But here's the real meat and potatoes...

The claim is that one of your diodes had instant poofage at 600mA with no cooling, but yet, another one ran just fine at 750mA sinked? Problem is, that would be saying enough heat was able to make it from the junction, through the package, through the module, and to the sink, all in enough time to prevent catastrophic damage to the cavity. If 600mA was _instant_ death, how did it survive 750? Laws of Thermodynamics suggests that the largest heatsink imaginable wouldn't make a difference.

BTW, if your LD is cooled below ambient (as with a well driven TEC), it actually uses _less_ I to make a given optical power. But that extra cooling power doesn't mean you can drive your diode harder... it only means you can reach max optical output with less I. 

As a side note... I've been suspicious of some of the output claims being thrown here around lately. There may be some meters either not well calibrated, calculating at the wrong wavelength, etc.

Now, I'm far from the world's foremost laser diode expert, but also quite far from the noob I was 4-5 months ago. Either way, if I can be proven wrong on the issues discussed, all the better learning experience for me and everyone else.

Re. CPU OC'ing. Although CPU's are indeed semi-conductors, they don't have optical parts subject to near instant failure. You'd have to load one up hard for a good 10 - 15 seconds with no sink before getting into trouble, maybe more. Fortunately, overclocking my Opteron 170 400MHz above stock didn't require upping the V, although I forced the step from 1.35V to 1.4V anyway to ensure stability. No matter heatwise though, because they're current driven devices as opposed to voltage driven... the heat is produced by the extra current under load. Very cool though (no pun intended) that the Opty comes with a quite beefy stock heatsink... saves the bucks on a tricked out sink.

Last items. 45 degrees C isn't that hot (113F). 16 - 18x LD's max at about 75C operating temp. Where in the heat chain are you measuring at, and what are you measuring with?

Very cool about the laser show thing. I don't have the funds to make even a ghetto projector system (in the proper sense), but have been thinking about sticking some shiny mirror pieces on a fan for low budget fun.


----------



## VaThInK

Did I mentioned anything about what I did is right? I don't remember that I did. Anyway, what I was trying to say is that to prove that one of your statement is not true.



> A heatsink would not have allowed my diode to live one minute longer.



Have you tried it personally to crosscheck my finding? I have proven it by running my diode for more than 1 minute. As I said without cooling it would die and go to diode heaven. I never said that by doing what I did would get me the theoretical lifetime as specified by the manufacturer. It is a fact that the more you overdrive an LD, it's lifetime is reduced greatly. But by applying a means of cooling this aging process can be reduced. Example:

Without cooling:
@300mA it will last 5000 hours.
@400mA it will last 1000 hours.
@500mA it will last 10 hours.
@600mA it die within minutes.

With some kind of cooling:
@300mA it will last 5000 hours.
@400mA it will last 3000 hours.
@500mA it will last 500 hours.
@600mA it will last 10 hours.

Note that those numbers are just examples not real world figures to show my point that it is possible.

Damage doesn't happen instantly, instead it grows gradually. Try to feed a 20mA LED with 100mA of current. It will die gradually, which indicates its lifetime is shortened rapidly. Unless if you apply a massive amount of current lets say 1A then it will speed things up even further.

I did say this in my last post.


> You're right though when you said that if the LD is driven too far, some kind of damage would've been occurring before the heat could even get away. But trust me cooling will also help.


Above statement means that the process can be reduced not avoided.

Please hold your nerve. I'm not trying to offend or insult you in any way. I was just trying to share my experience. I am definitely no expert in this area as well and maybe I just got lucky having such a durable LD. I will try again with the LDs from SenKat GB when I received them to confirm if my LD is acting weird or not.

I don't know what did I said wrong in my last post :thinking:.

Peace dude.


----------



## Gazoo

I would love to find a spec sheet for any of the open can diodes. Does anyone know where to find it?


----------



## VaThInK

Yeah, I would love to have one as well. Sadly I don't even know the part number of the LD. It's clean. Doesn't have any writings on it. So, I don't even know where to start to look for one. Anyone knows who manufacture this type of diode?


----------



## Gazoo

VaThInK said:


> Yeah, I would love to have one as well. Sadly I don't even know the part number of the LD. It's clean. Doesn't have any writings on it. So, I don't even know where to start to look for one. Anyone knows who manufacture this type of diode?



Mine didn't have any numbers on it either. I spent about an hour searching on google for anything that resembles it....nothing. Maybe I was looking in all the wrong places. I am curious to know the advantage of having it open as opposed to closed. Since it doesn't have a glass covering, it might be putting out a few more milliwatts than a closed can. Maybe it is cheaper to manufacture this way. But from what I could tell, the internal design is different than a closed can. If anyone knows please help us out with the specs.


----------



## Bimmerboy

VaThInK said:


> Anyway, what I was trying to say is that to prove that one of your statement is not true.



Let me know when you've acheived that. 



VaThInK said:


> Have you tried it personally to crosscheck my finding?



Why, technically you could say, yes, I did! 

When the module fails to show any change in temperature after a couple minutes, one can conclusively say that adding a heatsink for that duration will make no difference... at all.



VaThInK said:


> Example:
> 
> Without cooling:
> @300mA it will last 5000 hours.
> @400mA it will last 1000 hours.
> @500mA it will last 10 hours.
> @600mA it die within minutes.
> 
> With some kind of cooling:
> @300mA it will last 5000 hours.
> @400mA it will last 3000 hours.
> @500mA it will last 500 hours.
> @600mA it will last 10 hours.
> 
> Note that those numbers are just examples not real world figures to show my point that it is possible.



Hmmmmm....

Example: How long can I sustain flight by flapping my arms?

Without cooling:
@300 flaps per minute, I will fly for 5000 hours.
@400 flaps per minute, I will fly for 1000 hours.
@500 flaps per minute, I will fly for 10 hours.
@600 flaps per minute, I will die within minutes.

With some kind of cooling:
@300 flaps per minute, I will fly for 5000 hours.
@400 flaps per minute, I will fly for 3000 hours.
@500 flaps per minute, I will fly for 500 hours.
@600 flaps per minute, I will fly for 10 hours.

Obviously, cooling made a big difference here.

Note that those numbers are not real world figures. Just examples to show my point is possible. 



VaThInK said:


> Damage doesn't happen instantly, instead it grows gradually. Try to feed a 20mA LED with 100mA of current. It will die gradually, which indicates its lifetime is shortened rapidly. Unless if you apply a massive amount of current lets say 1A then it will speed things up even further.



Even this doesn't make sense, man! When's the last time you fed 100 mA to a 20mA LED? It will die a lot faster than "gradually". However, LED's have nothing to do with the conversation. These be LD's we be talkin' 'bout up in hea'. Not _regular_ ol' LED's.



VaThInK said:


> Peace dude.



Cowabunga dude! Gnarly! :nana:

P.S. Still waiting to hear about some more about the magical heatsinking techniques that allow an Amp through a LD, when only 600mA insantly kills one without it.


----------



## VaThInK

Bimmerboy said:


> Let me know when you've acheived that.



Haven't you been reading this thread :thinking:?



> Why, technically you could say, yes, I did!


Are you using the same diode as mine? If not try again :naughty:.



> When the module fails to show any change in temperature after a couple minutes, one can conclusively say that adding a heatsink for that duration will make no difference... at all.


In my case it didn't fails at all. My room was around 15C and it went up to around 45C within a couple of minutes.



> Hmmmmm....
> 
> Example: How long can I sustain flight by flapping my arms?
> 
> Without cooling:
> @300 flaps per minute, I will fly for 5000 hours.
> @400 flaps per minute, I will fly for 1000 hours.
> @500 flaps per minute, I will fly for 10 hours.
> @600 flaps per minute, I will die within minutes.
> 
> With some kind of cooling:
> @300 flaps per minute, I will fly for 5000 hours.
> @400 flaps per minute, I will fly for 3000 hours.
> @500 flaps per minute, I will fly for 500 hours.
> @600 flaps per minute, I will fly for 10 hours.
> 
> Obviously, cooling made a big difference here.
> 
> Note that those numbers are not real world figures. Just examples to show my point is possible.


Go Forest you can do it. Fly...! 



> Even this doesn't make sense, man! When's the last time you fed 100 mA to a 20mA LED? It will die a lot faster than "gradually". However, LED's have nothing to do with the conversation. These be LD's we be talkin' 'bout up in hea'. Not _regular_ ol' LED's.


Alright, I admit, LED is not a good example. Anyway, what I meant by "gradually" is not slower or the same as it would at normal operation. Just to clarify my self, I just tested to fed a couple of LEDs at 100mA and they run alright, except being slightly dimmer. At 2A they popped in seconds.



> Cowabunga dude! Gnarly! :nana:


Cowabunga! 



> P.S. Still waiting to hear about some more about the magical heatsinking techniques that allow an Amp through a LD, when only 600mA insantly kills one without it.


I guess you got nothing else better to do :thinking:. So you agree that 600mA with heatsink is doable now? Since you want me to show you my "magical heatsinking techniques that allow an Amp through a LD". If you insist, I'll show you soon. I have no spare time at the moment. Be patient alright :naughty:.

PS: If I'm not mistaken, Daedal just pushed his LDs from SenKat's GB to 600mA and he didn't mention anything about his LDs turning into LED so far.
Here you go: Link.

Cheers mate :twothumbs.


----------



## VaThInK

> _Originally posted by *Bimmerboy *at LPF_
> 
> You're joking, right? You haven't directly addressed a single question in your debate with me, nor even made sense in the attempt.


Care to point out which one? If my responses to your questions are all wrong, I really don't get you mate:thinking:. Please elaborate more.



> However, it's my mistake for not restricting the discussion to CPF, and giving you a poke here.


I don't have any problem with it :thumbsup:.


----------



## Gazoo

VaThink, I powered my diode from that group by with 500ma, but only for a second. It is still ticking. I did order a tiny peltier off of e-bay. I think it will be interesting to play with..


----------



## VaThInK

Gazoo said:


> VaThink, I powered my diode from that group by with 500ma, but only for a second. It is still ticking. I did order a tiny peltier off of e-bay. I think it will be interesting to play with..



Hi Gazoo, good to hear that. I haven't got mine yet unfortunately :shakehead. Maybe because I'm overseas, so it'll take longer. Anyway, have fun with it alright. You bet, you'll get heaps of fun playing around with them :thumbsup:. Hopefully when you got everything running, your result would match with my claim to prove to Bimmerboy that heatsinking an overdriven LD would helps in preventing an instant death .

Remember though, safety first. These LDs got some serious grunt underneath :naughty:.

Cheers mate.


----------



## Gazoo

Hi VaThinK, Yeah, I know...do at your own risk...lol But I have 5 diodes so I can afford to blow a couple of them. In fact I plan to order 5 more. For the price they are awesome...worth every penny. I hope you get yours soon. Mine came yesterday. I will update once I have had a chance to experiment with the peltier. I need to find a heat sink for it and a power supply. I am still thinking about mounting it to a cpu fan/heat sink I have with arctic silver adhesive. Still not sure how to mount the module to the peltier, but I have a few ideas. I do not want to give Meredith any more money if I can help it. I have no clue yet what I am going to use to power it with. It draws around 4 amps at 5 volts. I don't think I need to drive it that hard. I am thinking with 3 volts it will draw much less current, but be able to maintain enough cooling. I do wish there was an easy way to control the temp. Anyway, I am looking forward to it.


----------



## VaThInK

Hey Gazoo, I was told that aluminum clad resistors is a good candidate for mounting LD housing. I'm getting some of those for experimenting soon. With powering your TEC module, PC PSU is your best friend. Cheap and ample of power . In fact I use it as my "lab" power supply :thumbsup:. Where else could you get a 5V PSU at 30A for around $30? With 12V at 30A and the rest as well.

TEC module will always try to suck as much current as it's designed for. So if your TEC module is rated 5V at 4A and you're only powering it from a 2A Wallmart wall plugpack without any current regulator, the plugpack will overheat and there will be risk of fire hazard (you shouldn't try to pull out 2A from a cheapo 2A plugpack anyway for long term operation). Thus, current regulator is a must just like with LDs is you want to limit the cooling/heating power of the TEC module.

There is actually a simpler alternative than the ones I've suggested in the past to control your TEC module, but I can't draw it on top of my head now. I've build this circuit about 7 years ago! I vaguely remember it now. Basically it's somewhat similar to an LD driver circuit (utilize an op amp, a MOSFET/transistor and a handful of other discrete parts), but instead of just a pot, a thermistor is used as well. Hopefully someone who's good at this will be kind enough to give you some help to build one. Or try Google maybe?

Aluminum clad resistors in action: Link.
stanwax at Photonlexicon did that wonderful job. I can't wait to build mine soon .


----------



## Gazoo

Wow.. that is a very nice set up he has...thanks for the link buy it may be awhile before I go that route. For the time being I just want to get the TEC working. I had hoped to be able to power it by batteries and make it portable. Perhaps this is impossible? I completely agree about using a PSU from a computer in place of a lab power supply. I was looking around last night on how to get the supply to work...it is simple. And the range of voltages is quite impressive. One can even use the 3.3 volt output. No doubt a PSU would come in handy for many things. I have one I could strip out on an older computer but is a very cheap one..so I will order a new one. I think a 300 watt atx power supply would be sufficient...lol. Please note it will take me some time to get all of this working. But I am anxious. I would like to push my open can diode to the limits, but it is the only one I have so I will be working with the diodes from the GB, at least to begin with. I personally have no doubt cooling does allow more current to be applied before damaging the diode. For one thing, we know there are tiny little wires in the diode. As they heat up, they resist current flow. Cooling has the opposite effect and of course this is a good thing. However I have never had a diode go completely dead, rather they have turned into an LED. Bimmerboy stated in a previous post: "And when overdriven, damage happens to the mirrored facets of the resonant cavity, which a heatsink cannot prevent." Well given the amount of current that has been passed through diodes that have been cooled, it stands to reason this his statement is only true when the diode is not cooled. But we really need to know what the effect of cooling has on the mirrored facets. And it would be nice if we could find specs on the open can diodes, as well as if there are any advantages of the diode being open.


----------



## meddigo

Hey guys... been reading your thread here with interest! I'm definatly ordering parts to build my own at the end of the month... when I get paid!...

I know its practially impossible to tell about a diode just from telling you about a drive, however I know a couple of people here have used them from Lite-On drives. Just wondered what they are like? The drive I'm planning to get is the Lite-On DH-20A3P-12C. It's cheap lol at £18 (roughly).

Meddigo


----------



## Gazoo

Well on the previous page, I posted the model number of the LiteOn drive I harvested my diode from. It is the open can type. Since the drives are similar, it would not surprise me if the one you are buying will be the same. The only difference I can see is the one you are buying is not a lightscribe drive. Please keep us updated as I would not mind getting another open can diode cheaper if possible.


----------



## meddigo

Will do!

Do you think that a lightscribe would be a more powerful diode?

VaThink, wanted to ask where you live? I know you mentioned that you were overseas when waiting for those diodes you bought. Are you in the UK? If so any chance once I've built a laser could I send you it for a power test?

Final question... what denotes a lasers brightness?

Meddigo


----------



## Gazoo

Hello meddigo,
As I recall lightscribe burners came out around the same time as 16X DVD drives. I would be very surprised if a 20X burner with lightscribe has a diode that is more powerful than one without. 

As you know VaThink has had great success with open can diodes. We have not been able to find any specifications on them. However I think, and this is only my opinion, being that they are open can allows for a couple of advantages. One they run cooler, and two there is no glass obstructing the light, so more light is passing through the lens. How much more, we don't know. 

Two things denote laser brightness. The power of the laser and the wave lenght. For example, a 100mw red laser beam will appear to be just as bright as a 25mw green laser. These are probably not exact figures but from waht I have read I believe they are close. I don't have a green laser. I like red better and these do it yourself red lasers are much cheaper. But one day when I have the money I will get a greenie.

I live in the US ... sorry. I don't have a meter yet, I hope to next month.


----------



## Gazoo

VaThink,
I posted the following over at LPF but thought I would post it here too.

I did receive my peltier yesterday. It does not draw anywhere near 4 amps. At 3 volts it only draws about 500ma. At 6 volts it is drawing a little over an amp. For my testing I wired it up so the bigger flat side is the hot side. Then I applied a little arctic silver compound to the hot side and pressed it on a heat sink. There is nothing holding it on other then the arctic silver. The smaller square gets really cold. I am sure if I was using arctic silver adhesive and had it clamped down tight it would get even colder. But what surprises me the most is the small amount of current it draws. Lovely for making a portable device...

I put some small droplets of water on it and they froze within seconds. Then I laid an Aixiz module on it and it got freezing cold within a minute....with only 3 volts at 500ma. I know I am excited as this is the first time I have ever played with a peltier. I plan on flattening the front part of the module just a little bit, and using thermal adhesive to glue it on to the peltier. This way it will still be easy to unscrew the back side in case the diode goes poof. I might put some arctic silver on the threads of the module to help the cold conduct. I really need to get some arctic silver adhesive...lol.

I don't know if it is just me and I have some more experimenting to do. But I did cool down the module, and then ran 220ma through it. I know I can go higher but I wanted to see what the effect would be. Well it seems as though it is putting out more mw's when cooled. I don't have a meter yet. Has this been your experience


----------



## meddigo

Gazoo,

Thanks for your great reply ^_^ I'm definatly going to get a Lite-On drive then if they have the open cans in. Man I wish I had the money to buy it all now!! Haha. Unfortunatly I have to wait till the end of the month to get paid... 

Medd


----------



## VaThInK

meddigo said:


> Will do!
> 
> Do you think that a lightscribe would be a more powerful diode?
> 
> VaThink, wanted to ask where you live? I know you mentioned that you were overseas when waiting for those diodes you bought. Are you in the UK? If so any chance once I've built a laser could I send you it for a power test?
> 
> Final question... what denotes a lasers brightness?
> 
> Meddigo




Meddigo:
I doubt lightscribe drives would have more powerful LDs as you only need more power when you burn faster and as far as I know the lightscribe surface is basically the same as the data ones. So there would be no difference of power on the LD.

I live in Melbourne, Australia mate. It would be cost and time prohibitive to sent yours over, however I have no problem with it as long as you are willing to cover the return postage :thumbsup:. Another alternative would be to find other CPF member who lives in UK and have a power meter handy (and of course willing to do it for you :naughty.

I would also like to add on top of Gazoo response that beam diameter also affect the brightness slightly. At least to my observations so far. Bigger beam/dot always appears slightly dimmer compared to tighter ones.


Gazoo:
Weird that your peltier only consumes about an Amp at 6V when it is actually rated 5V at 4A. Maybe a typo on the spec sheet ? Anyway, it's good to hear that it's working great for you :twothumbs.

To be honest I have never tried to measure LD performance under different working temperatures, but I suppose it should be a little bit more efficient when cooled down (to manufacturer spec of course). I might actually experiment on this if my schedule allows me to. Just to be sure.

I just received my LDs and I did a short test to see what they're capable of as I can't hold my curiosity despite my busy schedule. The results isn't very satisfying to me for the time being. I only get 160mW average at 350mA without any cooling. I tried to bump the current up to 500mA again without any cooling and I couldn't see any gain in doing so (it heats up faster though :scowl. In fact the power output is dropping noticeably faster than at lower current. I will experiment more when I got the time.

On a side note, Robin from PL has informed me that the red LDs in 20x DVD burners are completely useless for us hobbyist as you can see on the pic I attached below. This thing is impossible to be mounted into anything due to its dimension. Steer clear from these drives guys.

PS: I'm not sure if this diode only exist in this particular model or all 20x models. I would assume all would employ this very same diode to be able to burn at 20x speed.


----------



## Gazoo

VaThink,
Someone at LPF posted a pic of the same type of diode. I hear they are powerful, but almost impossible to mount in anything. Everyone needs to take note of of the DVD burners that have been listed in this thread. I don't know how many 20X DVD burners use the diode in your picture, but it is best to play it safe. The open can diodes are awesome and mine did come out of a LiteOn 20X DVD burner.

I will be interested in the results of any more tests you can do on the diode from the group buy. I still feel they are worth the money. 160mw for the price of the diodes is a decent amount of power. And I know another person whom received it was getting 220mw of power output, and he uses the same meter as the one you have.


----------



## dave-gtturbo

awesome topic you guys have - i've got a laser diode stripped out of a Pioneer 112D dvd-rewriter drive and i've got all the bits n bobs ready to make a Maglite into a very high powered laser pen 

just waiting on my AIXIZ laser housing, then i'll be jammin, and i'll be sure to get some pics up here, with a power rating if i can get one (at uni, probably)!

nice work guys 

Dave


----------



## meddigo

Thinking about getting some of those diodes off LPF instead of getting a Lite-On. I'm gona guess your answer as yes, but do you rekcon it's worth it for my first build? Stupid question really considering I may blow one... haha!

Though I think I will get a lite on drive for an open diode at some point...

Medd


----------



## Gazoo

meddigo said:


> Thinking about getting some of those diodes off LPF instead of getting a Lite-On. I'm gona guess your answer as yes, but do you rekcon it's worth it for my first build? Stupid question really considering I may blow one... haha!
> 
> Though I think I will get a lite on drive for an open diode at some point...
> 
> Medd



Medd, the diodes in the group buy are worth every penny, and are perfect for beginners. I started out with diodes I was getting off of e-bay for $50.00 a pair and even they were worth it. I went through 4 of them in a hurry. Then I harvested diodes out of a few DVD ROM drives, my last harvested one being an open can. Still, I bought 5 diodes from the GB and intend to get a few more. I am still on my first one, they are not only powerful little buggers but are tough little buggers. For the price you can't go wrong.


----------



## dave-gtturbo

hey, i'd recommend the drive i used - Pioneer 112d (as recommended by VaThink) it is very easy to deconstruct, was very cheap to buy and the diode is an open can too  (plus - he managed to get 400mw thru it!)

get it here... http://svp.co.uk/products-solo.php?pid=2146 i got mine in two days for only £25.64  (including express shipping iirc)

Dave


----------



## Hemlock Mike

I am sold on "open can" diodes !! The one I built is direct drive from 2 - e2 cells ano outputs 280 mW. I recently harvested another open can and I'm building a TEC cooled module.....

Mike


----------



## dave-gtturbo

very nice mate, can't wait to get mine up and running - i just need my AIXIZ laser housing! hope it comes 2moro! if it does, i'll have it working 2moz, and i can't wait to try it 

Dave


----------



## Gazoo

Well I have my TEC all up and running. The cooling does seem to help the laser put out a bit more power. The little peltier I bought only needs 200ma to keep the diode cool. Also I found a neat dew point calculator. This will enable you to find out how much you can cool your module given the room temperature and humidity, and not have it condensate.

http://www.decatur.de/javascript/dew/index.html 

P.S. There is a group buy for the LPM-1 laser power meter. Check out the GB section of this forum if interested. All questions concerning the meter will need to be asked in the group buy thread. Thanks.


----------



## Hemlock Mike

VA -- Bummer -- I wanted to hit the 400 mark first -- Congrats 

I have an LG open can mounted in my TEC but I lost courage at 400 mA and 350 mW !!! Way to go -- Now I can push my limits farther.

At 350 mW, It slashes elec tape - - but 400 ?? I want to see that on my meter too 

Mike


----------



## VaThInK

Hi peeps,

Just wanna do a little update on the diodes from SenKat's GB. So far I've managed to push them to 350mA to 400mA max for long term operation and I get around 250mW out of them. This is when I mount them on emptied aluminum clad resistors. They still get quite warm after a while even when using this passive cooling method. I tried to cool them with TECs as well and the power output was very stable like a rock. Not bad for $13 a piece I must say but the open cans still beat them by a long way. However you would have to spend $17 extra to get an open can diode. In the end it's up to you really whether you want to spend the extra $$$ or not. Either way, they're both extremely great in value and performance :twothumbs.

Now I'm gonna start building my dual reds setup .

Cheers.


----------



## Gazoo

Hello VaThink,
I agree about the open can diodes. I did receive my Meredith module and mounting block. This time I ordered the one with the acrylic lens. It is a much better burner than the glass lens.

Powering the module (open can installed) with only 240ma's and TEC cooling, I was able to cut a match in half. It took a few passes and a few minutes, but I was impressed.


----------



## it_inspector

VaThInK said:


> Behold, is this freaky or what ? I just hit the 400mW mark on the dot ! And it was going steady down to 391mW. I rigged up this quick and dirty setup to proof to Bimmerboy that I did manage to get 345mW reading previously without peltier or active cooling but only using the laser diode housing from Aixiz on eBay. It turned out to be a bomb when I set the current to 700mA coupled with peltier cooler :twothumbs. By the way, thanks to SenKat for recommending LPM-1 to me. Just received it a few weeks back and now I can measure my findings. Such a great meter. Thanks again SenKat!



Hi there mate

What LD are you using there ???

Is that the open can from the Drive or the group buy one.

Thanks


----------



## Illum

not to open a can or worms but I can't help but wonder what you do with the burner AFTER you extract the diodes:candle:


----------



## dave-gtturbo

Illum_the_nation said:


> not to open a can or worms but I can't help but wonder what you do with the burner AFTER you extract the diodes:candle:


 
my drive just sat in the house, so i took the diode, and now it does the same 

first broke, so i've since bought a drive, and its just wasted to be honest...

Dave


----------



## VaThInK

it_inspector: It's an open can ones from Pioneer 112D.

Illum_the_nation: I recycle the rest of the parts as well .


----------



## it_inspector

VaThInK said:


> it_inspector: It's an open can ones from Pioneer 112D



Would you be able to help me mate, on the power supply for the Diode from 112D also how did u mounted it in the Axis Laser Diode Casing.

I have a casing and i am going to get 112D early next week as i am out in country area.

Thanks


----------



## VaThInK

it_inspector said:


> Would you be able to help me mate, on the power supply for the Diode from 112D also how did u mounted it in the Axis Laser Diode Casing.
> 
> I have a casing and i am going to get 112D early next week as i am out in country area.
> 
> Thanks



Well, a constant current source power supply is what you'll need to power them (remember that diodes are current dependent so this is crucial). Could be just a simple power resistor in series with the diode. The wattage and the resistance of the resistor depends on how many amps are you going to feed to the diode. Personally, I'm using a PC PSU, the 5V rail and put a 5 Ohms 15W pot in series with the diode for testing purposes. You could also use LM317/LM350/LM338 or their variants in current regulator mode if you want to, for better current regulation. Of course lab power supply would be the best option if you have one lying around. Sadly, I don't have this kind of luxury .

In regards to mounting a diode into AixiZ housing, it couldn't get any simpler. All you need to do is just simply pop it in inside the provided space (the 5.6mm aperture) and that's it you're set.

A word of advice, if you're planning to overdrive your laser diodes, don't run them for too long. They will overheat and die eventually. Personally I suggest to run them at or below 500mA ~ 600mA max (strictly for open cans as the others I've came across are much weaker) with some kind of proper active or passive cooling method. But then your mileage might vary. Trial and error.

Hope this helps.

Hmm, I think the demand for 112D would go through the roof at this time around because of you guys .

Cheers mate.


----------



## Gazoo

Hi VaThink,
I have a question. I know you said it is easy to get the 112D apart. But how easy is it to actually harvest the diode from it. 

I have a couple of Lite On drives on the way. One has to go back into my computer to replace the one I took out, and I screwed up the diode while harvesting it....

The other one I will harvest and be more careful. I have successfully harvested a diode out of a Lite On...the one I am using now. But they are a pain to get out.


----------



## VaThInK

Hi Gazoo,

I was meant to say that it's easy to take the diode apart from the drive. Not as easy as killing it though. But then, out of all the DVD burners I've tried, I personally think 112D is the easiest. Someone just PM me yesterday asking about how to extract the diode out of 112D. If you have managed to get down to just the diode with its heatsink, you'll need a plier to push them in opposite direction to get the diode out of its shell. Put one nose of the plier at the end of the diode (where the beam is emitted) and the other nose on the edge of the heatsink (near where the diode's pins are). Be extremely careful when carrying this operation as the diode is made out of soft metal unlike its closed can cousins, which is stronger. If you're not careful you could deformed its body (will cause the beam to misaligned) or chipped the laser die! Alternatively, you could use abrasive files or very fine precision cutting blades to cut it open if you have them handy.

Hope this helps.

Cheers mate.


----------



## petah

wow..600ma!!!! I wouldn't dare that power..... i'm workin' on a lg gsa-50n.. don't know the power output..... i'm putting in like 300 - 350ma at 2.4v, you guys know if raising the voltage to 3v it'll be ok or at that power i'll fry the diode?
thanks!


----------



## petah

...


----------



## petah

VaThInK said:


> 1. Sony
> 2. DRU-800A
> 3. Open diode
> 4. 342mW peak @ 650mA with good heatsink
> 
> 1. Pioneer
> 2. 112D
> 3. Open diode
> 4. 345mW peak @ 650mA with good heatsink
> 
> I assume most of the red diodes used in 18x DVD burners are the same. I've tried Samsung, LG and Lite-On 18x burners (forgot the model) as well with similar results to the above.
> 
> PS: Just keep in mind that these diodes get extremely hot real quick when being fed at 650mA without proper cooling (gets to 50C within 2 minutes with ambient room temp at 18C). So an active cooling such as fan assisted heatsink or peltier cooler is very recommended for longer duty cycle.
> 
> Cheers.


...
hey VATHINK???!!!
could you help me with some ideas???
I'm workin' on this laser project...."flashlight" I want the flashlight for the reason of carring around.. u know... "demostrating".. so i have to use batteries, but I don't know the best way to extract the maximum power of my lg gsa-50n open diode without ruining it.... should I use 2.4v at 300-350ma...... or 3.0v at 300-350ma or even 2.4v at 600ma... I have all these options.. and I don't wanna be imprudent testin' which one is the best way.... so... any idea?
I'd appreciatel!!!


----------



## Gazoo

VaThink, thanks...it helps. It sounds like the diode is mounted differently in the heatsink in the 112D, than the Lite On ones I have been harvesting from. It also is looking like the open can diodes are the same in the 112D as the 20X Lite On DVD. Next time I need an open can I will order the 112D.


----------



## Gazoo

Hi again VaThink...lol.
I found the following picture in another thread. This is exactly what the open can looks like mounted in its heatsink from a Lite On burner:







This came from a NexxTech 20x DVD burner. Do you recall if the 112D is mounted in the same type of heatsink? Thanks again.


----------



## VaThInK

petah said:


> ...
> hey VATHINK???!!!
> could you help me with some ideas???
> I'm workin' on this laser project...."flashlight" I want the flashlight for the reason of carring around.. u know... "demostrating".. so i have to use batteries, but I don't know the best way to extract the maximum power of my lg gsa-50n open diode without ruining it.... should I use 2.4v at 300-350ma...... or 3.0v at 300-350ma or even 2.4v at 600ma... I have all these options.. and I don't wanna be imprudent testin' which one is the best way.... so... any idea?
> I'd appreciatel!!!



I always run my lasers at 5V without any problem. Even the commercially made DPSS lab modules run off 5V. 2.4V sounds very low. You want to be feeding voltage a little bit above the laser voltage drop. In regards to the current, I can't really say for sure. Specific diode requires certain amount of current. Just to be on the safe side, I would say you should feed yours around 3.5V @ 350mA. Diode from 112D is the only one that can sustain 600mA so far based on what I can see. I haven't tried LG GSA-50N yet and I think I'll stick with 112D for now since it's good enough for me. Even if you use an open can diode, you wouldn't have any proper means to cool the diode down by dissipating the heat generated @ 600mA would you? Unless the flashlight body you are using is made out of thick aluminum and you are able to spread the heat to it, try not to go above 350mA. Especially for long term operation. You should try first at 350mA and see if the flashlight feels warm quite quickly or not. If not, you could try to bump the current a little bit.


Cheers mate.


----------



## VaThInK

Gazoo: Nah, the heatsink on 112D is quite different to that. The metal block where the laser die sits is exposed not covered like in that picture. That's why you can push it with a plier. Again just be extremely careful when doing so though. As I mentioned earlier, the body of the diode is made out of softer metal than the closed can.


----------



## Gazoo

VaThink,
Perfect and thank you. I was sure that was what you meant but I wanted to be sure. As you can see removing the diode from the heatsink as shown in the picture is a big pain. I am still thinking all open can diodes are the same no matter what drive they come from. Not only can they be fed with high current, they seem to hold up better. Mine is still running and I have run it as high as 400ma with no problems, and 350ma with long duty cycles. I can punch a hole through a floppy disc in under 10 seconds. When I get my LPM-1, then I will push he diode much more.


----------



## VaThInK

By the way, just for your information, Robin (the creator of Die4Thing and Die4Drive) told me that Rohm diodes are crap. They have a high failure rate when overdriven during burn in. So if you're planning on overdriving LDs, don't do it with Rohm LDs. Try to stay away if you can. I never tried them personally though.

Now I know why Bimmerboy haven't had much success overdriving his.


----------



## yuip

Yep, I've had 2 Rohm diodes die on me. However, I was using a resistor and a 6.3 Volt capacitor. I'm pretty sure that a huge voltage spike from the 2 AAs blew the cap and discharged into the diodes. I'm pretty sure that it wasn't because the diode became disconnected from the cap, because when I turned the laser off I disconnected the batteries. After about 15 seconds, I reconnected the batteries and the diode turned into an LED.

I only have 2 Rhom diodes left and I'm debating whether or not to try it with a capacitor with a higher voltage rating, even though I have purchased Daedal's circuit, which should be here soon.


----------



## Gazoo

yuip,
I would wait for the driver. Then run the diodes with a reasonable amount of current...less than 200ma's with short duty cycles. If the diode has an early death, then this will be one more confirmation that there is a problem with the Rohm diodes.

VaThink,
I have not had much luck overdriving any diode except for a diode I removed from a Benq drive and it was closed can. I was driving it with 240ma's with long duty cycles. But I was using a driver from another module. The only reason it went to the graveyard is because the positive leg came loose on it...it was my fault. 

The failures could be on account of my circuit and I have made improvements to it since my diodes died. Also I have a bad habit of leaving them on too long when trying to burn a hole through something. I have more coming and will test one by overdriving it with the same current as you did.

We know the open cans are very sturdy and well designed. So no problems with the open can, and I have been using my circuit to drive it.


----------



## petah

VaThInK said:


> I always run my lasers at 5V without any problem. Even the commercially made DPSS lab modules run off 5V. 2.4V sounds very low. You want to be feeding voltage a little bit above the laser voltage drop. In regards to the current, I can't really say for sure. Specific diode requires certain amount of current. Just to be on the safe side, I would say you should feed yours around 3.5V @ 350mA. Diode from 112D is the only one that can sustain 600mA so far based on what I can see. I haven't tried LG GSA-50N yet and I think I'll stick with 112D for now since it's good enough for me. Even if you use an open can diode, you wouldn't have any proper means to cool the diode down by dissipating the heat generated @ 600mA would you? Unless the flashlight body you are using is made out of thick aluminum and you are able to spread the heat to it, try not to go above 350mA. Especially for long term operation. You should try first at 350mA and see if the flashlight feels warm quite quickly or not. If not, you could try to bump the current a little bit.
> 
> 
> Cheers mate.


 
thanks a lot mate!!!!!!
I wouldn't imagine a diode running @ 5.0v... all I know about laser diodes I got from the internet..... n' so far all I've seen is laser projects running @ 3.0V at most........ but if you say it's ok going a little further.... I'll mount my flashlight with 350ma input power as you suggested..... and voltage around 3 to 3.5V.
thanks again buddy!!! my flashlight is aluminum made... and I'll try to do what you recomended... stick the heatsink to the body to spread the heat over...

....Cheers!!!!!


----------



## yuip

Hey Gazoo,

Thanks man. I don't really want to blow another diode, so I'm just gonna wait. And yeah, I've been planning to push it at 150-175mA and see if it lasts a while. I have a multimeter on order from DealExtreme, so it'll be easy to determine the maximum current that will be able to go through to the diode. :twothumbs

Luckily I have all 5 of my Sony diodes left, I haven't even taken them out of the plastic case SenKat sent them in.


----------



## Gazoo

I found running the GB diode at 160ma's, it was still one hell of a burner.:devil:

Which meter did you get?


----------



## VaThInK

Gazoo said:


> We know the open cans are very sturdy and well designed. So no problems with the open can, and I have been using my circuit to drive it.



Uhmm, I think It's actually the other way around. Open can diodes are more fragile than the closed cans. They're weak on three counts. Their body being softer, their laser die being unprotected and the two insulated pins cannot hold much pressure and will get loose overtime. I recommend that they should be mounted permanently and take the weak pins into account. Personally I've killed two of them as the result of this weakness. Be careful about this next time.


----------



## Gazoo

VaThInK said:


> Uhmm, I think It's actually the other way around. Open can diodes are more fragile than the closed cans. They're weak on three counts. Their body being softer, their laser die being unprotected and the two insulated pins cannot hold much pressure and will get loose overtime. I recommend that they should be mounted permanently and take the weak pins into account. Personally I've killed two of them as the result of this weakness. Be careful about this next time.



VaThink,
Sorry...by sturdy I meant in regards to the amount of current we can push them with and the long duty cycles..in other words they hold up very well to current. I am well aware of how fragile they are. 

The one I killed on account the leg becoming weak was a closed can diode. I have only successfully harvested one open can and it is still going just as strong as the day I harvested it.... July 22'nd.


----------



## yuip

Gazoo said:


> I found running the GB diode at 160ma's, it was still one hell of a burner.:devil:
> 
> Which meter did you get?



Nice, thanks for that. I'll have a try with 'em at 160mA then. The thing I really love about these reds is the on-the-fly adjustable focus, and the price of course! One day when I get brave I'll tear apart a 20X DVD Burner for an open can diode. Maybe I'll be able to duplicate VaThInK's 400mW peak. :naughty:

I got the larger Xiole DT9205A. The reviews said it was a pretty good meter, so I went with it over the smaller meter.


----------



## Gazoo

Lol...I would love to be able to duplicate his 400mw peak..but I am not going to try it until after I get my meter. My LiteOn's came today so I do have a spare burner ready for harvesting.

I did light a safety match form about 8 feet, but I had to boost the current to 350ma's. This was with my open can with TEC cooling. New record for me..

I fully agree with you about the reds...cheap and focusable. I think you will be quite happy running it at 160mw's. You should easily be able to light a match at 3 feet.

I think the bigger meter is better. It might not be backlit like the smaller one but for those prices they are both good deals.


----------



## yuip

I see, you just want bragging rights for hitting a measured 400mW. 

Wow! That's quite a nice achievement with the open can.

Three feet with the GB diodes? Nice. Maybe I'll be able to push out another two or three feet on that estimate. 

Yeah, I thought it was a bargain for a seemingly reliable DMM. I'll see how it performs when it gets here. I ordered it on the night of the 4th, and the meter still hasn't shipped!


----------



## chad123

What are you guys using for current measurements? 
I have two nice dmms and both of them have a 10 ohm resistance when measuring up to 250 mw. I know the meter has to have a voltage drop across a resistor to extrapolate the current but 10 ohms is a big deal when you are talking about 3. something volts and a dropping resistor of an ohm and a half or so for the diode.
This would seriously skew results. 

Any comments?

Chad


----------



## Gazoo

Yes and you have made a very good point. I recently learned by placing a 1 ohm resistor is series with the diode, and measuring the voltage across the resistor, this would be the same as a current reading. I checked it against the 10 amp reading on my meter and it was very close...close enough I permanently soldered the 1 ohm resistor in my circuit and it is what I now use to measure current.

It is also much safer too because the build up of voltage of a capacitor in a power supply can kill the diode if the diode is connected after the power supply is turned on. So now I have everything soldered in permanently and I no longer have to worry about bad connections from my meter being in series with the diode.


----------



## petah

HEY U GUYS!!!!!!!!
any idea for collimating???????
I have my dvd laser diode (open package) mounted in a flashlight, created a cooling system, 3,4V at 350ma power input as vathink recommended...... but I'm having some problems in collimating the beam, I don't have access to aixis case or stuffs like that from where I live, so any suggestion?
I'd appreciate!!!


----------



## yuip

Where do you live? Can DealExtreme ship to you?

DealExtreme has the AixiZ modules for $4.30 shipped. Just buy one from them. 

If DX can't ship to you, then use a some sort of small lens. It will be difficult to collimate the beam without some sort of lens holder, but you can get the diode's beam down to a small dot from a few millimeters or centimeters away.


----------



## petah

yuip said:


> Where do you live? Can DealExtreme ship to you?
> 
> DealExtreme has the AixiZ modules for $4.30 shipped. Just buy one from them.
> 
> If DX can't ship to you, then use a some sort of small lens. It will be difficult to collimate the beam without some sort of lens holder, but you can get the diode's beam down to a small dot from a few millimeters or centimeters away.


.....
thanks for replying mate!!!!!
I'm living in Brazil...... and don't know about this DealExtreme... I'd pay a few bucks for an Aixis module... no problem, can u give me some more details about DX?
thanks again buddy!!


----------



## yes8s

Hi guys,

A few days ago I saw the "how to make a DVD laser" video and I've been bitten with the laser bug. I been reading all sorts of info on the net and now I want to build one ASAP. 

I've got a few Aixiz modules on the way but I am a little unsure of what laser to get. For now, I plan to build one pointer that would be somewhat impressive and can do the usual - 
light a match
pop a balloon 
burn through plastic/tape etc.

Initially I was going to get the Sony closed can LD from the GB or similar closed can LD but after reading this forum I'm leaning more towards the open can LD from a PIONEER DVR112D ( i have found for $38AUD ) after VaThinks recommendation. I'm pretty good with electronics but I'm a little unsure of just how fragile the open can LD would be. Do I really need to worry about this? Also, I am conflicted on whether I really need to regulate the current (with the LM317 circuit) or just limit the current in the form of a resistor. The only heatsinking would possibly be from a torch casing - what would be the safe limit in terms of mA's for this LD with a strong Po.

I want this first one to last for a while. Will this setup work for what i want? Any other advice would greatly be appreciated.

Also VaThink:
I too am from Melbourne do you know of anywhere in Oz I can get just the LD's or a cheaper burner and do you know of a good easily obtainable pocket sized torch I can use to house the laser.

Thanks in advance guys for the advice


----------



## yuip

petah said:


> .....
> thanks for replying mate!!!!!
> I'm living in Brazil...... and don't know about this DealExtreme... I'd pay a few bucks for an Aixis module... no problem, can u give me some more details about DX?
> thanks again buddy!!



No problem. Here is the normal AixiZ module's product page at DealExtreme. DealExtreme is located in Hong Kong, and their majority of orders are probably from the US. I checked their Help page to see if the shipping was extra to Brazil, and they said that there was no addition charge to ship to other countries outside of the US, but naturally it would take longer. If you ordered from DX I would expect it to take 3-4 weeks for delivery using the standard air mail.


----------



## IgorT

Hi guys!

Is there a general consensus yet on which DVD burners jield the best/strongest LDs?

I took apart a Samsung SH-183 LightScribe Super-WriteMaster and both LDs looked like the one on the picture in post #83 in this thread.

I was dissapointed, but i managed to hook up the red one to a regulated PSU, at 3V. The current was 200mA and there was quite a flood of red light on my desk.

I decided i would try to mount a collimator in front of it anyway, but the third time i hooked it up, the output suddenly started dropping and went to nothing in a few second.

All together it was not on for more than 10 seconds, before this happened.

Before i destroy another burner, i would at least like to know i will find what i'm looking for inside.


Thanks!

Igor


----------



## VaThInK

yes8s said:


> I'm pretty good with electronics but I'm a little unsure of just how fragile the open can LD would be. Do I really need to worry about this?



Well, that depends on how sloppy you are . But I strongly suggest that you pay more attention when handling this little beast. I have pulled the positive pin once myself accidentally, so I consider it to be more fragile than the closed one. If the positive pin is pulled out, you can still use it though if you happen to have a good magnifying glass. Make another connection from the other pin (not the negative one) with a thin wire (I mean really thin) by using the finest soldering tip available (I used 0.8). Then you just have to touch the laser die with the wire and you're done. The diode would come back to live again :thumbsup:. I have actually done this with the one I broke and it works.



yes8s said:


> Also, I am conflicted on whether I really need to regulate the current (with the LM317 circuit) or just limit the current in the form of a resistor. The only heatsinking would possibly be from a torch casing - what would be the safe limit in terms of mA's for this LD with a strong Po.



Using a current limiting resistor is fine, but if the voltage changes, the current would also be affected. So it's not a good idea to use a current limiting resistor when powering from battery. LM317/LM350/LM338 can be configured to provide constant current source regardless the input voltage. 350mA is safe enough for the diode to be used in longer duty cycle and it provides enough juice to produce >200mW. Just remember, power density is important if you want to burn stuff. That means at 200mW, the smaller the beam diameter, the better burner it will be.



yes8s said:


> I want this first one to last for a while. Will this setup work for what i want? Any other advice would greatly be appreciated.



I don't think anyone would be able to give you a definite answer on this one. This would depends on how good is your cooling, how hard you overdrive it, how stable is your power supply, how long are you going to run it for, etc. Having said that, I think at 350mA you should be fine with a duty cycle of 15 mins ON and 5 mins OFF. Maybe more, maybe less. I'm not too sure. You'll just have to experiment with it yourself. Another word of advice, never ever let its own beam (or any other laser beam for that matter) get into the face of the diode. This will kill it instantly! *So watch for back reflection*.



yes8s said:


> Also VaThink:
> I too am from Melbourne do you know of anywhere in Oz I can get just the LD's or a cheaper burner and do you know of a good easily obtainable pocket sized torch I can use to house the laser.



Personally I don't know where to source LDs or small torch for cheap locally. With torch you can get them from eBay or DX quite cheaply. For DVD burners, MSY sell 112D for AU$38 last time I checked. Probably you quoted your price from them too .



yes8s said:


> Thanks in advance guys for the advice



You are more than welcome mate :thumbsup:. Have fun and play safe alright.


----------



## petah

yuip said:


> No problem. Here is the normal AixiZ module's product page at DealExtreme. DealExtreme is located in Hong Kong, and their majority of orders are probably from the US. I checked their Help page to see if the shipping was extra to Brazil, and they said that there was no addition charge to ship to other countries outside of the US, but naturally it would take longer. If you ordered from DX I would expect it to take 3-4 weeks for delivery using the standard air mail.


 

..thanks a bunch yuip!!!!!!!
I'll order one right now.. and then wait a while.....
do u happen know the diameter of the beam made by this module?
is it thin enough for burning?
don't know da output power of my "red beast" but I think it's gonna be strong enough for popping balloons.. light a match n' things like that after setting the collimating lens since I'll be feeding it with 3.4V @ 350ma!!!!
appreciated buddy!!!!


----------



## Kenom

yes8s said:


> Hi guys,
> 
> A few days ago I saw the "how to make a DVD laser" video and I've been bitten with the laser bug. I been reading all sorts of info on the net and now I want to build one ASAP.


 
I'd like to know where you saw that movie. I've got a complete walkthrough on how to make your own dvd burner laser and would like to see what everyone else has out there. Preciate it!


----------



## yes8s

Kenom said:


> I'd like to know where you saw that movie. I've got a complete walkthrough on how to make your own dvd burner laser and would like to see what everyone else has out there. Preciate it!



This is what i stumbled across:

http://www.instructables.com/id/EWM4YR2F4WY1LQ2/?ALLSTEPS

you may have seen this:

http://www.felesmagus.com/pages/lasers-howto.html


----------



## yuip

petah said:


> ..thanks a bunch yuip!!!!!!!
> I'll order one right now.. and then wait a while.....
> do u happen know the diameter of the beam made by this module?
> is it thin enough for burning?
> don't know da output power of my "red beast" but I think it's gonna be strong enough for popping balloons.. light a match n' things like that after setting the collimating lens since I'll be feeding it with 3.4V @ 350ma!!!!
> appreciated buddy!!!!



The diameter is as big or as small as you want it too be, from probably a quarter millimeter to about 4 millimeters, becuase it is focusable.

Oh yeah, a DVD burner diode will definitely pop balloons. In my opinion I would feed it a little less juice than what you plan, just to see how you like it's burning ability. Ramp it up if you aren't satisfied. But at 350mA, keep the duty cycle pretty short (20-30 seconds on, a minute or two off).

I think you'll find you'll be more than happy with your laser, especially if you drive it at 350mA. Keep in mind that the harder you drive it, the less lifetime it will have. You can't even really estimate how much the life of the diode will be decreased, so it's a risk you have to be willing to take.

Have fun, and good luck! :twothumbs


----------



## petah

yuip said:


> The diameter is as big or as small as you want it too be, from probably a quarter millimeter to about 4 millimeters, becuase it is focusable.
> 
> Oh yeah, a DVD burner diode will definitely pop balloons. In my opinion I would feed it a little less juice than what you plan, just to see how you like it's burning ability. Ramp it up if you aren't satisfied. But at 350mA, keep the duty cycle pretty short (20-30 seconds on, a minute or two off).
> 
> I think you'll find you'll be more than happy with your laser, especially if you drive it at 350mA. Keep in mind that the harder you drive it, the less lifetime it will have. You can't even really estimate how much the life of the diode will be decreased, so it's a risk you have to be willing to take.
> 
> Have fun, and good luck! :twothumbs


 

thanks mate!!! !!
I don't intend to have a duty cycle longer than 10 secs or so.... just pop a balloon and "off" light a match and "off"... but I'll consider what you're sayin'.... I think I'll start with 300ma and then see what happens.. if it satisfies me I'll stay around that... "why take chances right!"
thanks for your attention mate, I ordered the aixiz module you recommended me yesterday... still a few weeks to go...."crazy" lol... can't wait.....

appreciated buddy!!!!


----------



## petah

hey yuip?????
just one more thing.........
What voltage do you run your diode at?
@ 5V like vathink does?


----------



## Bimmerboy

Some food for thought for peeps using the basic resistor/cap setup to consider.

It may be good insurance to avoid the use of some types of momentary switches, especially ones with longer travel and/or cheap ones, and even _more_ so if you're driving the diode beyond spec. This is for two reasons.

I've found the travel in more than one type of momentary to be less than clean, which is likely to send multiple spikes through the circuit as you press the button. Since the resistor/cap can only do so much in terms of filtering, the diode's gonna' take a beating.

Also, with a momentary under your finger, now I can only speak for myself, but I'm a heck of a lot more tempted to be hitting that button much more often than flicking the toggle switch back and forth (my plastic box laser has both). 

Thinking back to when the Rohm laser bit the dust... what was I doing with it? Playing with the button. 

I replaced it with another Rohm of the same type in early August, and took it to a weekend long party up in da' hills. It stood up fine to considerably longer runtimes than it normally sees, and I only used the toggle...as will be the case from now on. Of course time will tell, and all diodes within the same batch are slightly different, but if this diode lives a lot longer than the last one, it would suggest against the use of momentary switches without a CC circuit and proper filtering.

Anyway, this laser kicked butt! At night I shined it diagonally across a large open field to the opposite corner... probably about 2 mi. distance. Using the Aixiz module to focus on the trees, the dot was intensely bright, and the beam was nice and strong. Everyone was impressed and fascinated by it. More fun than a barrel o' monkeys!

BTW... even with the extended duty cycles, the Aixiz module showed virtually no rise in temperature.


----------



## Bimmerboy

Ha... well that distance estimate was fairly off.  So much for judging by eye.

Happened to be on Google Maps last night, thought of this last post, and checked it out. In reality it was about 3/4ths of a mi. :sigh:

I'll be back to the same place next August, and will have much longer distances picked out in advance (also thanks to Google Maps). Judging by the dot intensity at 3/4 mi., it should be able to reach out a LOT farther.

Anyway, just wanted to correct the error.

So who's got good stuff to report on with their DVD diode projects?


----------



## Kenom

I've now got my lasers for sale in the marketplace. Check out the bargain. Nice build quality.


----------



## petah

hey... How u doin' guys?
I'm back to thank vathink and yuip for your recommendations....
I have my "laser pointer" all done.. flashlight shape....
I'm feeding it with 3.4v @ 300ma.. I know I could push it a little harder but I want this goodness to last a while so....even so... it's very powerful.. I just popped a balloon more than 20 feet away... matches ignite almost Immediately when just few feet away....
thanks a lot you guys!!!
and yuip? thanks for the dealextreme tip...... the laser module fit just fine for my project.... I have already ordered a greenie pointer from them... of course I'll modify for more power too...
thank again mates...


cheers!!!


----------



## yuip

Hey petah,

Sorry I didn't get to reply to your message about input voltage. It's nice to see that you didn't feed it with 5 volts, because I imagine that would kill it. At 3.4V, while that may be a little high, should be fine. It might generate a bit more heat, but if you have a good heatsink and/or keep the duty cycle short it should last you a long time.

If you don't have any goggles to protect you against the red wavelengths, I strongly suggest you get some!

What DX green did you get? They seem to be decent lasers for the price, although I don't have one myself. When you get the greenie, I assure you that you will be amazed how bright it is. Your red is probably doing about 150-200mW, and just a 30mW greenie will look even brighter.

Have fun, and be careful!


----------



## petah

yuip said:


> Hey petah,
> 
> Sorry I didn't get to reply to your message about input voltage. It's nice to see that you didn't feed it with 5 volts, because I imagine that would kill it. At 3.4V, while that may be a little high, should be fine. It might generate a bit more heat, but if you have a good heatsink and/or keep the duty cycle short it should last you a long time.
> 
> If you don't have any goggles to protect you against the red wavelengths, I strongly suggest you get some!
> 
> What DX green did you get? They seem to be decent lasers for the price, although I don't have one myself. When you get the greenie, I assure you that you will be amazed how bright it is. Your red is probably doing about 150-200mW, and just a 30mW greenie will look even brighter.
> 
> Have fun, and be careful!


 

yeah yuip..... I kinda imagined that 5.0v d' be a little too high.... and I've built a good heatsink to my diode... I created a "pool" around the laser module I got from DX, since water is said to be a good cooler... is doing just fine.. thanks again buddy!!!
and about the greenie I ordered.. it's a 30mw one... but i'll short it for more power...
I'll let you about it.....
it was shipped last friday (10/19) so it will take like 2 weeks to arrive..

cheers mate!!!


----------



## dr_lava

It's not a DVD burner, but the PS3 laser replacement modules 'Rock For Diodes'. See the group buy is my sig. sorry if this is an ad, i'm just so excited about this. maybe too excited


----------



## IgorT

*DVD Burner question 1*

Hi guys!

I posted a question before on what the best DVD Writer for this application might be, but never got an answer...

I got a *Samsung Super-Writemaster SH-S183*, *18x DVD+R/18x DVD-R / Lightscribe* (.....) and was sure it would do the job.. Unfortunately when i got it appart, i was at first wondering where the diode is in the first place..

In the end it was the weird flat thin square thingy, like the one that was shown in the pic on the page #3..

I thought i would use it anyway, since some laser pointers have such a diode in them, but then i tested it with my lab PSU and forgot to limit the current.. After only three tries, the laser diode started dying at aroung a 200mA of current draw..


Well anyway, i made an arrangement with a computer company, to give me all the broken writers that were out of waranty.

Yesturday i got another *Samsung Writemaster, this time it was a TS-H552 ver. U*. I googled the specs and found out it was a *16x DVD+R / 16x DVD-R*. (EDIT: i made a mistake before assuming it wasn't ver. U,but it is.. the older version would be only 12x DVD-R...)


I was worried that inside it would have the same weird flat thingy, but man i was wrong!

It has a nice closed can laser diode. I know you guys prefer the open can ones, but i'm happy that it at least isn't the weird flat kind...

This time i did limit the current to 100mA at first. It gave a nice flood of red light on my desk. I tried it up to 200mA and it still works nice. It doesn't even get warm.


*So my question is*: What is the max safe current to drive this diode whith?

I'll be making a simple laser driver circuit today, but would like to know, how hard i can drive it..



*I do have another question*:
I was under the impression the IR LDs were even stronger than the red ones in these drives.. I also tried to drive it with 100mA first and 200mA later, and tried to view the result on a CCD camera, since they're IR sensitive..

What i don't get is, it hardly lighted up as much as an IR LED would. What's up with that?


*And yet another one:*
Is there an approximate relation between the power going in (mA) and the power going out (mW)? I know this can't be too exact, but a guess would do.. EDIT: What i meant was LD efficiency.. Does anyone know what it is?
Like for example 70% efficiency would mean 30% turns to heat and the rest to light.. Do such infos exist?


Thanks!


Igor


----------



## IgorT

*DVD Burner question 2*

I just got four more "broken" drives from the service of my computer company..

Another *Samsung Writemaster TS-H552U* and a *TS-H553B*. I have to google the specs of the second one yet, but i assume it might be the one with only 12x DVD-R...

I also got two CD-RW combo drives, with DVD readers, but no writing capabilities..

Does anyone know what the mW specs for readers LD's are?

What about the IR LDs in the CD writers? Do they give off any heat? I mean, they should, but on a CCD it lights up less than an IR LED would...

What voltage should i be driving these at and what current?



Thanks!


Igor


----------



## dr_lava

*Re: DVD Burner question 1*



IgorT said:


> *So my question is*: What is the max safe current to drive this diode whith?
> 
> I'll be making a simple laser driver circuit today, but would like to know, how hard i can drive it..
> 
> 
> *I do have another question*:
> I was under the impression the IR LDs were even stronger than the red ones in these drives.. I also tried to drive it with 100mA first and 200mA later, and tried to view the result on a CCD camera, since they're IR sensitive..
> 
> What i don't get is, it hardly lighted up as much as an IR LED would. What's up with that?
> 
> 
> *And yet another one:*
> Is there an approximate relation between the power going in (mA) and the power going out (mW)? I know this can't be too exact, but a guess would do.. EDIT: What i meant was LD efficiency.. Does anyone know what it is?
> Like for example 70% efficiency would mean 30% turns to heat and the rest to light.. Do such infos exist?
> 
> 
> Thanks!
> 
> 
> Igor



The max safe current depends on the diode, your heatsink, cooling, and the length of life you want. 200mA is generally considered safe, with a heatsink. you DO want a heatsink.

The IR LED may appear weaker if you camera has an IR filter.

the efficiency depends on drive current and sensitivity of the laser. If you assume the lasing threshold is 50mA, asd after that the laser gives 1mW per 1.3 mA increase, and the diode forward voltage is 2.8V, the efficiency can be calculated. At 200mA this would be 20.5% efficiency for input power to light power the stated parameters. The rest is radiated as heat.


----------



## dr_lava

*Re: DVD Burner question 2*



IgorT said:


> Does anyone know what the mW specs for readers LD's are?
> 
> What voltage should i be driving these at and what current?
> 
> Igor



Not sure, but you can guess 12x shouldn't be as powerful as 16x. Guess you can test them!


----------



## IgorT

*Re: DVD Burner question 2*



dr_lava said:


> Not sure, but you can guess 12x shouldn't be as powerful as 16x. Guess you can test them!


 
I think you misunderstood my question..

It was about the CD-RW combo drives, that only read DVDs, but don't write them.. I assume, these also have a red LD for reading the DVD. These would be much weaker than DVD writer LDs, but they might make a good laser pointer >1mW maybe even >10mW..

So i was wondering if anyone knows the DVD readers LDs output power...

Or do the combo drives use the IR LD for reading the DVDs?


BTW: I will definatelly be testing them A LOT since i have an almost unlimited supply...


----------



## IgorT

*Re: DVD Burner question 1*



dr_lava said:


> The max safe current depends on the diode, your heatsink, cooling, and the length of life you want. 200mA is generally considered safe, with a heatsink. you DO want a heatsink.


Thanks! That's the info i was looking for..
BTW: I always use cooling where needed.. I might adapt (bend) an IC heatsink with fins and wrap it around...



dr_lava said:


> The IR LED may appear weaker if you camera has an IR filter.


Actually on the camera the IR LEDs (for example from a PicooZ transmitter) light up VERY much. Sometimes they even blind the camera..

That's why i was wondering how it's possible that an IR Laser Diode shows up less light when viewed by the same camera...



dr_lava said:


> the efficiency depends on drive current and sensitivity of the laser. If you assume the lasing threshold is 50mA, asd after that the laser gives 1mW per 1.3 mA increase, and the diode forward voltage is 2.8V, the efficiency can be calculated. At 200mA this would be 20.5% efficiency for input power to light power the stated parameters. The rest is radiated as heat.


So is 20% the average efficiency of LDs or are you just making a guess based on this calculation?


Thanks!


Igor


----------



## carmangary

Hi all. I have read through here but I am still unsure of which one will do what I want. I need one to be able to do 200mw continuous. I will have it heatsinked of course. Has anyone run that hard continuously without it failing?


----------



## Gazoo

carmangary said:


> Hi all. I have read through here but I am still unsure of which one will do what I want. I need one to be able to do 200mw continuous. I will have it heatsinked of course. Has anyone run that hard continuously without it failing?



I run my open can with 400ma's with a TEC. This provides an output of ~230mw's. The diode was harvested from a Pioneer 112D burner.

I am sure you can run it without a TEC but you will have to keep your duty cycles short...it heats up quickly.


----------



## VaThInK

*Kind of off topic but here's what I did recently.*

Recently I was experimenting to combine 2 beams of red DVD-RW diodes into 1 more powerful beam. It was a success and here's the outcome. I measured the output at the end and it was putting out around 600mW after about 5% of loss from the optics. I just thought you guys might be interested in what I was up to.

Some pictures with comments:




The setup. All of the fixtures are built from DVD-RW housings. Good enough for the job I must say.




600mW of red photons. Roughly around 30mW is lost as the result of the PBS cube used in this setup.




600mW red + 100mW green = 700mW yellow. Red and green beam diameters are around 4mm and 1mm respectively.




Front view of the above. I reckon 5~6:1 is the perfect power ratio to get a nice shade of yellow :naughty:.




700mW of yellow photons hitting a brown cardboard. Very intensely bright and a great burner for sure .

What's next? I'm saving money to get a 150mW blue to complement this setup. I'm guessing with 150mW of 473nm I would get a nice and pure white color mixture. I can't wait to get my hands on one of them and start building RGB setup. They're so damn expensive though . Wish me luck guys :thumbsup:!


----------



## IgorT

*I just killed my second LD.. What am i doing wrong?*

Hi guys!

I was testing the red LD from a 16x DVD writer, by hooking it up to a LAB PSU.

The first one was the weird flat thing besides i forgot to limit the current, so i'm not upset..

The second one was a closed can, and i used the same lab PSU at 3V and limited the current to 100mA... 

For a while it worked fine, then i wanted to test a collimator lense, and suddenly there was no imput anymore. I looked at it and it was hardly lighting up.. The same thing that happened to the one before...


But shortly before this happened i touched the negative terminal and felt a shock.. It seems i was statically charged, but i don't know if this static voltage went to the PSU (more likely since it was hooked up) or the LD (less likely, since the positive lead was not hooked up)


Or it could be something else entirely and i should be using a LD driver circuit instead of the PSU?

I'm building one anyway, but i'm a little bit sad, since now i'm down to two strong red LDs, untill i get more from the repair shop of the computer company...


----------



## cy

what type of safety glasses is everyone using for these powerful laser mods?


----------



## VaThInK

cy said:


> what type of safety glasses is everyone using for these powerful laser mods?



I'm using Laser Gard at the moment. Got a bargain on eBay. Costing me $10 for 2 pairs . One is for red and the other one is for green or blue.


----------



## IgorT

VaThInK said:


> I'm using Laser Gard at the moment. Got a bargain on eBay. Costing me $10 for 2 pairs . One is for red and the other one is for green or blue.


 

Just one question... The protection glasses for red lasers are green and for green lasers red, am i right?

Thanks!

Igor


----------



## VaThInK

IgorT said:


> Just one question... The protection glasses for red lasers are green and for green lasers red, am i right?
> 
> Thanks!
> 
> Igor



Use red tinted ones for green or blue lasers. For red lasers, usually blue tinted ones are used instead.


----------



## IgorT

Gazoo said:


> I did receive my Meredith module and mounting block. This time I ordered the one with the acrylic lens. It is a much better burner than the glass lens.


 
Hi Gazoo!

I was wondering... Which Meredith module are you using? Do they offer just the casing and the lense, or do you have to buy one with an LD?

Also, is it better than the AixiZ module?

I don't want to kill any more LDs, so i have to order some case, that will cool the LD at least a little..

I also just bought a 15x15mm Peltier TEC. What would be the best way to go from here on?


Thanks!


Igor


----------



## IgorT

Since this is a thread on what DVD writers yield the best LDs, i would like to add the following two:

- *Samsung Writemaster TS-H552 ver. U* specs:16x DVD+R / 16x DVD-R

- *Samsung Writemaster TS-H552 ver. B *specs:16x DVD+R / 12x DVD-R


Both yield nice closed can type LD, with some cooling they should be able to withstand 200mA or more. I just bought a Peltier TEC, so i will make a few more tests..

The only down side is, that they are soldered into place, onto two steel pieces, and it's hard to get them out.. It takes a very long time to unsolder them, since all the heat goes into the steel parts and the solder doesn't want to melt.. I used a dremel, to remove as much solder as possible, without heating the LD too much... Of course cutting pieces away also generates a lot of heat, but at least you can do a little at a time, while you can't do the same with solder.. If you try to unsolder it, you have to heat the ENTIRE piece complete with the LD enough for the solder to melt.. I would imagine, this could damage or kill it, but i don't understand, how they manage to solder them there in the first place without killing them...


A writer i would definatelly NOT RECCOMEND is the *Samsung Super Writemaster SH-S183 lightscribe*. Its a 18x DVD+/-R, but it has the weird thin flat LD, that can't be mounted anywhere easily.. If i recieve any more of this model however, i will test it some more (this time more carefully) to see if it's any good at all.

I hope this info helps someone.

Good luck!


Igor


----------



## IgorT

VaThInK said:


> I did mine using peltier because it is easier for me. I already got it set up and ready to run and I don't have a heatsink built up ready for testing. I have heaps of them lying around in my storage though. Something like 30+ heatsink fan modules but I just don't have enough free time to do it :thumbsdow.
> 
> Peltier can go as low as -20C without any load acting on the cold side, so it will freeze water no problem. When heat is applied to the cold side, it will drop significantly of course. The hot side is very hot, hence the huge heatsink. This particular ones have a cooling/heating power of 240W.


 
I wanted to ask you how you drive the peltier element.. Then i noticed your particular one has a power rating of 240W!

The strongest i've seen so far was 123.5W and is 50x50x4mm.. What are the dimensions of yours?

Just yesturday i bought a Peltier, but it's a very small one (15x15x5mm) and has a power rating of 3.9W and 1.9V specification..

Still i think this should be enough to cool the LD down quite a bit..

But i have a question..

Since it says "voltage: 1.9V, current 3A", should i make a separate power supply for it, or can i drive it from the same power source as the LD (3V) and just regulate the current down accordingly,to get to the same power?


Any info would be appreciated, and since you said you have a bunch of these, i'm hoping you know something about them...


Thanks!


Igor


----------



## VaThInK

IgorT said:


> I wanted to ask you how you drive the peltier element.. Then i noticed your particular one has a power rating of 240W!
> 
> The strongest i've seen so far was 123.5W and is 50x50x4mm.. What are the dimensions of yours?
> 
> Just yesturday i bought a Peltier, but it's a very small one (15x15x5mm) and has a power rating of 3.9W and 1.9V specification..
> 
> Still i think this should be enough to cool the LD down quite a bit..
> 
> But i have a question..
> 
> Since it says "voltage: 1.9V, current 3A", should i make a separate power supply for it, or can i drive it from the same power source as the LD (3V) and just regulate the current down accordingly,to get to the same power?
> 
> 
> Any info would be appreciated, and since you said you have a bunch of these, i'm hoping you know something about them...
> 
> 
> Thanks!
> 
> 
> Igor



No special TEC driver was used during that test. Since it was only for a quick test, I simply fed the TEC 12V @ 8A and that's about it. Mine is rated at 15V @ 16A. You should use TEC driver though in normal situation to regulate the temperature properly.

I have seen as high as nearly 500W and 60x60mm in size. Mine is the same as yours, 50x50mm.

TEC is not really necessary if you're only running your diode <300mA for long operation or <600mA for short term operation. A heatsink with or without a fan would be more than enough under those circumstances mentioned above. In my previous post where I combined 2 beams together, I ran my diodes @ 600mA each for a couple of hours and they're fine. The optical power output was dropping slowly after a while though. So active cooling might help in my situation. Notice I only use aluminum clad resistor housings to help dissipate the heat.

If you want to use TEC with your diode, it is wise to power them separately so that it wouldn't disturb your LD.

Good luck mate :thumbsup:.


----------



## IgorT

VaThInK said:


> I have seen as high as nearly 500W and 60x60mm in size. Mine is the same as yours, 50x50mm.


Actually the one i bought is 15x15mm It's small enough to fit into a smal housing for the laser and add cooling..

The reason i became obsessed with cooling is the fact i killed two LDs by now.. One Samsung 18x (the weird flat kind in post #83 in this thread) and one Samsung 16x.. I'm down to two DVD writers.. One TS-H552 ver.B and one ver.U The ver.B is 16x DVD+R and 12x DVD-R. The ver.U is 16x DVD+/-R. So i'm hoping the second one is stronger, but they could be the same...

I don't want to kill any more LDs, at least untill i recieve some more drives from the repair shop..



VaThInK said:


> TEC is not really necessary if you're only running your diode <300mA for long operation or <600mA for short term operation. A heatsink with or without a fan would be more than enough under those circumstances mentioned above. In my previous post where I combined 2 beams together, I ran my diodes @ 600mA each for a couple of hours and they're fine. The optical power output was dropping slowly after a while though. So active cooling might help in my situation. Notice I only use aluminum clad resistor housings to help dissipate the heat.


 
You drove them at 600mA with just passive cooling? That is impressive...

You're using the Pioneer open can ones, right?


Thanks for the info!


Igor

P.S. I don't think the Peltier would cause any interference.. Just use up more current.. But i will check on an osciloscope just in case... And maybe use a stronger capacitor...

Wish me luck! Oh, you already did.. Thanks! 


EDIT:
An aditional problem i have is that the Samsung LD cans are soldered onto some big chunks of nickle plated brass.. It's hard to get them out.. If i tried to unsolder them i might kill the LD..


----------



## IgorT

One question guys...

How do i calculate the current going through a LD by measuring voltage across a resistor?

I read somewhere here this is how you guys do it and that it's better than putting a multimeter in series with the LD...


Thanks!


Igor


----------



## IgorT

*Finally a working laser!!!*

Hi guys!

I just had my FIRST successfull test of the Samsung Writemaster TS-H552 version B's laser diode (16x DVD+R / 12x DVD-R ..... i'm saving the version U for later, since i'm hoping it's stronger)

Since i don't have an AixiZ module yet, i had to improvise, using a lens from a cheap laser pointer..

I didn't unsolder the LD from the metal plate.. Instead i glued heatsinks on it..

And it worked PERFECTLY! I slowly went up to 280mA and it hardly warmed up (35 degrees celsius, measured with an IR non contact thermometer)

I finaly have a working laser! It's not yet burning anything, but it has a nice visible beam..

It could probably do more than 300mA. With the peltier even more..



Thanks to everyone who helped with answers and infos!


Igor


----------



## Kenom

*Re: Finally a working laser!!!*

those samsung drives are insane. I've gotten 9 of those flat ones and they die pretty quickly. I've got a picture of one. that and occasionally you will see these.


----------



## HRUDKA

Can anybody tell me, what are the ways to cool the LD? Is there any active cooling system?


----------



## IgorT

HRUDKA said:


> Can anybody tell me, what are the ways to cool the LD? Is there any active cooling system?


 
There is an active cooling system.. We just discussed it a few posts ago.

It's called a Peltier Thermo Electric Cooling element (TEC) It has tvo ceramic plates and when you apply current to it the electrons start flowing from one to the other.

One side gets extremely cold, the other gets hot (cos all the heat is "pumped" to it)

You have to attach your LD to something flat, that then touches the cool side (with some of that paste in between)

At the same time you have to put some passive heatsinks on the hot side... This way the Peltier can dissipate more heat and pump more of it away from the LD..

They are avaliable in different sizes and power ratings..

I bought the smallest one (15x15x5mm / 1.9V / 3A / 4W power) to be able to include it in an enclosure.. If i would do so, i would cut a hole in the enclosure and mount the peltier in a way that it's hot side sticks out of the enclosure and mout the passive heatsink on it there (outside)

Inside it would do all the cooling..


BTW: After killing my second LD i also got obsessed with cooling, but passive cooling is more than enough at 300mA for example.

If you mount your LD to a huge chunk of metal heatsink, you can drive them even stronger, cos the heat now has somewhere to go..

I believe a Peltier should only be considered if you want to seriously overdrive the LD and are limited in space at the same time (if you want to make things small)

As long as you're building things on your table (and can mount them on big heatsinks) or are not overdriving them, you don't need a Peltier.


----------



## IgorT

*Re: Finally a working laser!!!*



Kenom said:


> those samsung drives are insane. I've gotten 9 of those flat ones and they die pretty quickly. I've got a picture of one. that and occasionally you will see these.


 

The first drive that i disassembled (Samsung Writemaster SH-S183 - 18x DVD+/-R) Had exactly this type of LD in it.. At first i was confused and thought i haven't yet found the LD, then when i realized this was it, i was extremely dissapointed..

And it also died VERY fast..

Unfortunatelly i am kind of limited to Samsung, since my source mostly only sells these.. I was worried they would ALL be this weird square flat thingy type, but luckily i was wrong..


The 16x ones are the can type.It's the closed can, but at least it's not this flat piece of ****.


Right now i'm using the *TS-H552* ones (v. B - 16x DVD+R / 12x DVD-R).. Unfortunately, as i said before, they are soldered to one piece of metal, that is then soldered to yet another piece, which is then screwed into the optical assembly.

I'll try to attach a pic.. 







It looks and is attached in exactly the same way as the version U (16x DVD+/-R).. Could even be the same LD, but i used this one first just in case i killed it AGAIN...


To unsolder it, i would have to heat EVERYTHING up to the solder melting point (including the LD that is).. I'm worried this would kill it.

The only way to get this one out safely, is to carefully and slowly dremel it out.. I used a diamond plated cutting disc and cooled it in between with a cooling spray.

I only removed the outer chunk of metal, and left it soldered to the inner one. Since it's soldered, it has a VERY good heat transfer.. I then glued heatsinks to the sides of the inner chunk of metal and it worked perfectly!

I'm just happy that i finally have an LD that seems to work and hasn't died yet..

But i did have to get creative with the lens assembly.. In the end it worked out ok and made a wonderfully visible red beam.


----------



## MatajumotorS

I did get open can LD from LiteON LH-20A1P it is 20x. 
At 200mA it gets little warm after 5min in Axiz module. Had not tested it at higer rates. But it seems to me higer power than my previous LD with closed can from 16x, and it runs Mutch cooler. 

Question:
Do someone get some artifacts in LD beam of theese diodes? It is second one that i got. With optics there is some kind of "wings" line like in beam, well seen at 2-10m distance. Without the optic beam patern is not soft oval linear, but there is some kind of lines on sides of oval, causing the "wings". Will post pictures on monday.

Someone seen something like that?


----------



## IgorT

MatajumotorS said:


> I did get open can LD from LiteON LH-20A1P it is 20x.
> At 200mA it gets little warm after 5min in Axiz module. Had not tested it at higer rates. But it seems to me higer power than my previous LD with closed can from 16x, and it runs Mutch cooler.
> 
> Question:
> Do someone get some artifacts in LD beam of theese diodes? It is second one that i got. With optics there is some kind of "wings" line like in beam, well seen at 2-10m distance. Without the optic beam patern is not soft oval linear, but there is some kind of lines on sides of oval, causing the "wings". Will post pictures on monday.
> 
> Someone seen something like that?


 
I was getting some artifacts in my beam, but i thought it was from the bad lense.. Have to check again...


So you say the Liteon is a good one? Those are available here.. I might buy one.. Thanks!


----------



## IgorT

*Re: Finally a working laser!!!*



Kenom said:


> those samsung drives are insane. I've gotten 9 of those flat ones and they die pretty quickly. I've got a picture of one.


 
BTW: Kenom... Do you remember what drive it was you got this one out?

I know they are weird and hard to mount anywhere, but since they do 18x DVD writing, they should still be just as strong as the others, right?

Why the hell do they die so soon then? I'm thinking i did something wrong, but don't want to spend more money on another one..


Sooner or later i'll start getting a lot of these as well from the repair shop, and then i'll try to do some more testing, with proper heat sinking and a protection circuit this time of course...

If i can make any of them work, i'll post the results.. Untill then these 16x i have will have to do.


BTW: Which ones are better? The Pioneer 112 (18x) or the LiteOn LH-20A1P (20x)?

Both are open cans.. But does anyone have more info on them?

Years ago i remember all drives having a spec sheet with them that stated the power of the laser inside.. Now this info is hard to find for some drives...


----------



## laserblue

Can anyone tell what is the type of laser diode in an LG-H10A dvd-burner?
i'd like to dissect my dvd-burner but i'm not sure what to expect.


----------



## HRUDKA

IgorT said:


> There is an active cooling system.. We just discussed it a few posts ago.
> 
> It's called a Peltier Thermo Electric Cooling element (TEC) It has tvo ceramic plates and when you apply current to it the electrons start flowing from one to the other.
> 
> One side gets extremely cold, the other gets hot (cos all the heat is "pumped" to it)
> 
> You have to attach your LD to something flat, that then touches the cool side (with some of that paste in between)
> 
> At the same time you have to put some passive heatsinks on the hot side... This way the Peltier can dissipate more heat and pump more of it away from the LD..
> 
> They are avaliable in different sizes and power ratings..
> 
> I bought the smallest one (15x15x5mm / 1.9V / 3A / 4W power) to be able to include it in an enclosure.. If i would do so, i would cut a hole in the enclosure and mount the peltier in a way that it's hot side sticks out of the enclosure and mout the passive heatsink on it there (outside)
> 
> Inside it would do all the cooling..
> 
> 
> BTW: After killing my second LD i also got obsessed with cooling, but passive cooling is more than enough at 300mA for example.
> 
> If you mount your LD to a huge chunk of metal heatsink, you can drive them even stronger, cos the heat now has somewhere to go..
> 
> I believe a Peltier should only be considered if you want to seriously overdrive the LD and are limited in space at the same time (if you want to make things small)
> 
> As long as you're building things on your table (and can mount them on big heatsinks) or are not overdriving them, you don't need a Peltier.


 

Thanks very much for the answer, im not gonna make some big overclocking, just a little bit to make the beam hot  Do you think, that AiXiz heatsink (for about 5$) is enough?


----------



## Kenom

*Re: Finally a working laser!!!*



IgorT said:


> BTW: Kenom... Do you remember what drive it was you got this one out?
> 
> I know they are weird and hard to mount anywhere, but since they do 18x DVD writing, they should still be just as strong as the others, right?
> 
> Why the hell do they die so soon then? I'm thinking i did something wrong, but don't want to spend more money on another one..
> 
> 
> Sooner or later i'll start getting a lot of these as well from the repair shop, and then i'll try to do some more testing, with proper heat sinking and a protection circuit this time of course...
> 
> If i can make any of them work, i'll post the results.. Untill then these 16x i have will have to do.
> 
> 
> BTW: Which ones are better? The Pioneer 112 (18x) or the LiteOn LH-20A1P (20x)?
> 
> Both are open cans.. But does anyone have more info on them?
> 
> Years ago i remember all drives having a spec sheet with them that stated the power of the laser inside.. Now this info is hard to find for some drives...


 
Yeah I can tell ya exactly what drive I got this from..
Micro Advantage 16DDVDRW-A13 
it was pretty powerful but not as much as a pioneer 112d. I ended up toasting them cause I didn't have a module that fit them just right and they ended up getting pretty hot.


----------



## HRUDKA

*Re: Finally a working laser!!!*

OK guyz, can anyone tell me which is the best DVD burner to make powerfull laser beam with just an Aixiz module? From the previous post I can see the leading burners like LG, Lite-On, Pioneer, what burner do ya recommend guyz?  Im pretty obsessed with mounting LDs from burners, but have no experience in this topic 

Thanks in advance.


----------



## Gazoo

Vathink,
Your setup is awesome...I hope to get there one day. Thanks for sharing, I am very tempted to get a PBS cube and another Meredith module.

I have found a TEC will help the diode put out a few more milliwatts of power. And you are correct, as the diode heats up it puts out less power. I had mine running at 240mw's and when I shut the TEC off, the power dropped to 170mw's. At that point I turned the diode off...it was beginning to get hot.

I have my LPM-1 now so I don't have to guess anymore...it is great to have.

IgorT,
I am using two LM317' to control current going to my diode and peltier, and they are running off of the same power supply.


----------



## IgorT

HRUDKA said:


> Thanks very much for the answer, im not gonna make some big overclocking, just a little bit to make the beam hot  Do you think, that AiXiz heatsink (for about 5$) is enough?


 
Since the AixiZ module is a "big" chunk of metal, a lot of heat can be dissipated into it..
As long as you're not going over 250mA (maybe even 300) this should be enough..
Also remember, the heat you feel on the outside of the module is much lower than the heat in the LD itself.


The module does not disperse much of the heat to the air however.. You'd need a heatsink with fins for that and some airflow..

*Active cooling:*
You could also mount the AixiZ module with those resistor housings (in the VaThInK's combined beam pic above) to a metal plate, this metal plate to a Peltier's cold side, and a heatsink with fins to the warm side of the Peltier.. You HAVE to cool the hot side of the Peltier element with a heatsink or else it can not pump the heat away from the LD. It can actually start heating the LD if you don't cool the warm side of it.

If you're doing stuff on your table, you can mount the hot side of the Peltier to a large metal heatsink (scavanged from somewhere, usually aluminum, but copper would be better)

If you want to make it portable, you can use a CPU heatsink with a small fan on the hot side of the peltier.. The fan might not be necessary.. This is what i wanted to do at first actually.. 

This setup would be good for overdriving the LD, but it can still die and it's impossible to predict when.


*Improvised passive cooling:*
Right now my LD is working well, so i'll leave the peltier for something else.. I left it soldered into the metal chunk, and glued small IC heatsinks with fins to either side. Since i'm not gonna drive it harder than 200-250mA, i hope this is enough... I will monitor the temp in the beginning tho..

My biggest problem right now is mounting the optics in the right spot for the best efficiency....


Good luck with your project!


EDIT: *HRUDKA*, I wanted to add something.. LD -> aixiz module -> metal plate -> Peltier -> CPU heatsink -> fan (active cooling) is a too complicated setup for low power applications..

You could just as well simply attach the LD directly onto the CPU heatsink and add a fan to it.. Much less complicated and would still work VERY good. This is how CPUs are cooled. Peltiers (or water cooling (or a combination of both)) are only added when seriously overdriving the CPUs..

But i read on laserpointerforums that a 16x LD can light a match at 150mA so even the heatsink and fan are probably overkill.. An aixiz module is good enough for 150mA and more.


BTW: Sorry for the long post. I just want to make sure the explanation is as clear as possible..


----------



## IgorT

Gazoo said:


> IgorT,
> I am using two LM317' to control current going to my diode and peltier, and they are running off of the same power supply.


 
Thanks for the info!

So the LM317 are used for current regulation while the Peltier is connected directly to the power source?

What are the specs of your peltier and what voltage is it connected to? Do you have to limit the current to the peltier?

Since my peltier's specs say "voltage 1.9V, current 3A, power 3.9W" and my power source is 3V i think i would have to add a pot, to adjust it to the 3.9W. I'm afraid it would be overdriven otherwise...

What do you think?

EDIT: I calculated i have to limit the current to 1.3A with a 3V power supply to achieve 3.9W.. I will need a very small, 4W resistor to achieve this... But that is for my next project.. Right now my Phaser is nearing completion...


----------



## HRUDKA

IgorT said:


> Since the AixiZ module is a "big" chunk of metal, a lot of heat can be dissipated into it..
> As long as you're not going over 250mA (maybe even 300) this should be enough..
> Also remember, the heat you feel on the outside of the module is much lower than the heat in the LD itself.
> 
> 
> The module does not disperse much of the heat to the air however.. You'd need a heatsink with fins for that and some airflow..
> 
> *Active cooling:*
> You could also mount the AixiZ module with those resistor housings (in the VaThInK's combined beam pic above) to a metal plate, this metal plate to a Peltier's cold side, and a heatsink with fins to the warm side of the Peltier.. You HAVE to cool the hot side of the Peltier element with a heatsink or else it can not pump the heat away from the LD. It can actually start heating the LD if you don't cool the warm side of it.
> 
> If you're doing stuff on your table, you can mount the hot side of the Peltier to a large metal heatsink (scavanged from somewhere, usually aluminum, but copper would be better)
> 
> If you want to make it portable, you can use a CPU heatsink with a small fan on the hot side of the peltier.. The fan might not be necessary.. This is what i wanted to do at first actually..
> 
> This setup would be good for overdriving the LD, but it can still die and it's impossible to predict when.
> 
> 
> *Improvised passive cooling:*
> Right now my LD is working well, so i'll leave the peltier for something else.. I left it soldered into the metal chunk, and glued small IC heatsinks with fins to either side. Since i'm not gonna drive it harder than 200-250mA, i hope this is enough... I will monitor the temp in the beginning tho..
> 
> My biggest problem right now is mounting the optics in the right spot for the best efficiency....
> 
> 
> Good luck with your project!
> 
> 
> EDIT: *HRUDKA*, I wanted to add something.. LD -> aixiz module -> metal plate -> Peltier -> CPU heatsink -> fan (active cooling) is a too complicated setup for low power applications..
> 
> You could just as well simply attach the LD directly onto the CPU heatsink and add a fan to it.. Much less complicated and would still work VERY good. This is how CPUs are cooled. Peltiers (or water cooling (or a combination of both)) are only added when seriously overdriving the CPUs..
> 
> But i read on laserpointerforums that a 16x LD can light a match at 150mA so even the heatsink and fan are probably overkill.. An aixiz module is good enough for 150mA and more.
> 
> 
> BTW: Sorry for the long post. I just want to make sure the explanation is as clear as possible..


 
OK, thanks for the answer. Its good idea to attach LD to a PCs cooling system, because its invented for the best results. But if you wanna make your laser mobile, you should just regulate the mA going to the LD or just buy more expensive heatsink with cooling system. Thanks for your help again. I appreciate that.


----------



## HRUDKA

One little thing IgorT, what do you use as power supply and what do you recommend as the less complicated solution. It would be hazard not to use a resistor, so I am gonna buy one, but I wanna know an opinion of a experienced man like you


----------



## VaThInK

Gazoo: Thanks for your comment. Don't worry mate, you'll get there one day. I had so much fun building mine and I'm sure you would too . In regards to PBS cube, there's a group buy going on over at photonlexicon forum for good quality PBS cubes centered at 633nm and 473nm for $30 a piece. I'm not sure if they are going to take new order though. Just drop by and ask if you're interested. I hope you are not too late to order some.

IgorT: Very good explanation you got there mate :twothumbs. In regards to TEC, I think you kind of misunderstood on their power requirement. TECs are voltage dependent components. Of course you can limit their current to give you variable cooling/heating power, but they will always consume current roughly around what the data sheet state at their rated voltage no matter how much current you supply to them (I use 30A PSU for mine and they only consume about 16A, which is within spec). Giving higher voltage than the rated input could also damage the TEC elements permanently. Lower voltage than the rated spec will results in the TEC consuming less current, hence voltage dependent. With diodes you can feed them 5V even though they're actually rated at 3V. They will eat 3V in the end, but you have to pay great attention to their current requirement since they're current dependent. TECs are similar to light bulbs whereas diodes are exactly the opposite when it comes to power requirement. I hope you understand what I'm trying to say :naughty:.

PS: I just would like to remind you all that open can diodes from Pioneer 112D and Sony 16x drives are the only diodes that I know capable of withstanding current greater than 300mA when properly heatsinked. All the other diodes that I've tried just died sooner or later at this current and I don't know about the others since I haven't tried them all. Right now I'm just using diodes from Pioneer 112D as they yield spectacular results based on my findings.

Cheers guys.


----------



## IgorT

HRUDKA said:


> One little thing IgorT, what do you use as power supply and what do you recommend as the less complicated solution. It would be hazard not to use a resistor, so I am gonna buy one, but I wanna know an opinion of a experienced man like you


 
Well, i'm not really experienced with lasers.. Yet.. 

But i work with electronics professionally (R&D), so i have some basic knowledge i can apply here..


My power supply is VERY simple, since i want it to work from 3.6V (single cell LiPo, or three AAA NiMhs)

The LiPo i'm using is from a broken helicopter that i desparately wanted to destroy and (if possible) use it's parts for something else..

The LiPo was two 130mAh FullRiver cells wired in series (7.2V), but i rewired it in parallel, to get 260mAh, while still keeping half of the circuitry, that protects it from undervoltage and overcurrent (and exploding )...

I can send you a schematic for the LD "driver" i'm using.. It's extremely simple, but i had problems squeezing it in the little "Phaser" enclosure, so i made another circuit without a board.. (just the parts soldered together)

I can also post pics of it, once done.

Connecting the LD directly to batteries works for some, but a little current limiting is much safer.. And if it's adjustable it's even better.

From my results, i figured out i need only a 1 Ohm resistor to get to a high enough voltage. A small pot is added in series to this, to adjust for less powerfull LDs. A capacitor is in parralel with the power source, to protect from voltage spikes, and a diode before it, to decrease the voltage from 3.6V to 3V.

Now i can finally put it all in that small enclosure i have (it's made for miniature remote controlls, like a garage door opener for example).

I'm also considering to put a special warning LED with integrated circuitry, that would warn me if the voltage drops too low (in case the LiPo's PCB doesn't work well after rewireing..


Of course, if you don't have enough experience, (or many LDs to kill) you'd be better off using a more "complicated" (safer) driver circuit. Like the one with the LM317. But you'd still need a way of measuring the current, while setting it up.

Then you need a 6V power source and a larger enclosure, to fit all the batteries (5x AAA NiMhs)... A two cell LiPo would also do and be smaller, but more expensive. Especially one with protection circuitry.. They also need special chargers...

If i forgot something, just ask...


----------



## IgorT

VaThInK said:


> IgorT: Very good explanation you got there mate :twothumbs. In regards to TEC, I think you kind of misunderstood on their power requirement. TECs are voltage dependent components. Of course you can limit their current to give you variable cooling/heating power, but they will always consume current roughly around what the data sheet state at their rated voltage no matter how much current you supply to them (I use 30A PSU for mine and they only consume about 16A, which is within spec). Giving higher voltage than the rated input could also damage the TEC elements permanently. Lower voltage than the rated spec will results in the TEC consuming less current, hence voltage dependent. With diodes you can feed them 5V even though they're actually rated at 3V. They will eat 3V in the end, but you have to pay great attention to their current requirement since they're current dependent. TECs are similar to light bulbs whereas diodes are exactly the opposite when it comes to power requirement. I hope you understand what I'm trying to say :naughty:.


 
I know what you mean, but since my TEC is rated for 1.9V, while my power supply is 3V, i have to either use diodes in series, to lower the voltage acordingly, or use a resistor to limit the current, since at 3V it would consume 50% more power and probably kill itself.. As you said yourself, they are voltage dependant, so i need to take care of that...

I am new to lasers and TECs as well, but i have some experience with electronics, since i have to do it for work (R&D)...


EDIT: So your TEC is rated for 3V? And you use some diodes, to drop the voltage from 5 to approx 3V? That was the info i was looking for..

EDIT EDIT: I just had this funny thought, that if you were to overdrive a TEC it would require cooling, maybe by another TEC..


----------



## HRUDKA

Yep, Im gonna use the way with the LM317, because it is safer, as you say. If I understand I need to get current under 250mA and voltage about 6V? OMG its too much, isnt it? It would be written somewhere on the burner, what voltage does it require?


----------



## IgorT

VaThInK said:


> PS: I just would like to remind you all that open can diodes from Pioneer 112D and Sony 16x drives are the only diodes that I know capable of withstanding current greater than 300mA when properly heatsinked. All the other diodes that I've tried just died sooner or later at this current and I don't know about the others since I haven't tried them all. Right now I'm just using diodes from Pioneer 112D as they yield spectacular results based on my findings.


 
You just have to make me drool, don't you.. I really need to get that Pioneer drive.. 

Unfortunatelly my source of free LDs is somewhat limited to Samsung.. I could get lucky one day, but not "Pioneer-112D" lucky...

I'm happy with the TS-H552 ones right now, since the one i'm playing with right now, did 280mA continuous, just by being glued onto a small CPU heatsink.
Now i'm putting it in a small enclosure with a LiPo and a small protection circuit.. Wish me luck with the positioning of the optics.. (i don't have the aixiz modules yet)

BTW: Were those Sony 16x LDs from a group buy not rated for only 80mA continuous? Or was that 80mW continuous? Or are you talking about different ones?


----------



## IgorT

HRUDKA said:


> Yep, Im gonna use the way with the LM317, because it is safer, as you say. If I understand I need to get current under 250mA and voltage about 6V? OMG its too much, isnt it? It would be written somewhere on the burner, what voltage does it require?


 

You misunderstood me.. Voltage INTO the LM317 is 6V. Once it gets to the LD it's only 3V and the current is regulated.

If you use that circuit, you don't have to worry too much.. Just make sure you're grounded whenever handling a LD, and when you build the circuit, start at a smaller current and slowly work up from there..

I'm hoping you do have a multimeter, right?


----------



## HRUDKA

IgorT said:


> You misunderstood me.. Voltage INTO the LM317 is 6V. Once it gets to the LD it's only 3V and the current is regulated.
> 
> If you use that circuit, you don't have to worry too much.. Just make sure you're grounded whenever handling a LD, and when you build the circuit, start at a smaller current and slowly work up from there..
> 
> I'm hoping you do have a multimeter, right?


Yes, thats EXACTLY what I thought, I ve just expressed like a newbie  Thanks for help, btw how much does LM317 cost in US or whatever youre from? Im from CZ, so its a little bit harder to hunt out these things,..and I worry, that it would be definitely more expensive then in US

Of course I have a multimeter, heh  Its a basic tool in the house in these days 

OK I ve found it in our CZ eshops, its just a funny prize - only about 0.4 in USD. The shipping will be more expensive then the main product, LMAO


----------



## IgorT

HRUDKA said:


> Yes, thats EXACTLY what I thought, I ve just expressed like a newbie  Thanks for help, btw how much does LM317 cost in US or whatever youre from? Im from CZ, so its a little bit harder to hunt out these things,..and I worry, that it would be definitely more expensive then in US


 
You don't have to worry about the cost of a LM317.. It's such a basic component, it should be pennies, no matter where you live.. I'm from Slovenia, BTW, not the states.. So i'm a little closer to you..

Just make sure, you get the big one.. The one with a metal piece on top, with a screw hole.. Those can handle more current, than the small ones and you can mount them on a heat sink if needed..

If you get the small ones, you can solder three in parallel, and they could do 300mA, but that would be close to their limit..


BTW: What will you be using as a power source? Do you have a lab PSU, or is it gonna be batteries?

If you have a nice PSU, you can limit the max. current there, just in case something goes wrong with the circuit.. But that can only happen if you wire it wrong..

On a PSU you can also monitor the current going through the LD, instead of putting the multimeter in series.. That's how i tuned the circuit, before using a battery with it. It's best to leave the diode soldered to the driver constantly, it's harder to kill it that way..


Anyway, good luck!


EDIT: I see you found the price, while i was writing..


----------



## HRUDKA

I had PSU, but its lost somewhere in old stuff, coz I havent used it for a long time. It was an old type of PSU, so I dun think, that the it would be easier to handle then with the batteries, anyway. So I will use the batts.

I found the type with max. 1.5A output, it would be enough.


----------



## IgorT

Ok, here are some pics of my "Phaser"... 

The first is a part of a miniature enclosure with a LiPo, a switch and some very simple protection circuitry.. It's not yet wired completely, and it lacks the LiPo protection PCB... The switch is positioned at such a weird angle, cos the enclosure had a button hole there.. It takes a lot of place this way, so i had to solder the components together without a board...








The second is the LD, glued to two IC heatsinks and an adjustable lense holder on top.







It's very hard to position the lense perfectly for max output.. But once i'm done it will all fit into the nice small enclosure and work nicely.. (I hope... )


Wish me luck!


Igor


----------



## IgorT

One question guys.... How many mA does a 16x LD usually require to do some "burning"?

Someone said the Sony 16x LD from a group buy can light a match at only 150mA.. Is this true? What is the output power at that current?



I just finished building my laser and managed to make a nice narrow beam.. The current going through it is set to a little less than 200mA.

Do i have to focus the beam much narrower? What distance should it be focused at to light a match?

It could be i just have bad optics and it'll get better with the AixiZ module..

Anyway, here is the pic of the finished "phaser"... It came out very small, just like i wanted it.. The enclosure is meant for making remotes, like for a garage door opener or something...






Specs:

LD: TS-H552 16x at 200mA
Optics: Scavanged from a cheap laser pointer
Power supply: 260mAh LiPo with protection circuitry.
LD Driver: Simple protection circuitry with current adjustment possibility.
Dimensions: 74x44x18mm
Output power: God only knows... I could compare it to a known power LD tho, using a solar cell..


----------



## VaThInK

My TEC is rated at 15V and I was supplying 12V to it. In your case you could use a series of power diodes to drop the voltage down or better yet use a voltage regulator.

About LM317 or similar voltage regulators, they can work in 2 ways. To regulate voltage or to regulate current. They can't do both at the same time. You will need 2 of them working together to regulate current and voltage. So, if you use them as current regulator, the output voltage would be input voltage minus their voltage drop. Example: 6V - .6V = 5.4V for LDO regulator. 5V is safe though to use with laser diodes. I always power mine with 5V and in fact commercially made ones usually use 5V anyway.

The Sony 16x LD I mentioned is not the ones from GB as they're closed can. I had a Sony 16x drive that uses open can just like with Pioneer 112D. With the GB LDs 150mA ~ 200mA is good.

For burning, adjust the beam diameter as tight as you can. This way will provide more power per area. No point in having 200mW at 10cm diameter. It's just gonna act like a mini flashlight and lose its power density. Ideally, you would want to focus all of the optical power to 1 tiny spot to achieve maximum burning capability. The focus distance would depends on how far away is the object. Green laser doesn't really need to be adjusted though as the beam diameter at the aperture is already very tight (~1mm compared to ~5mm for direct injected red), so you just need to make the beam parallel and maintain it.

PS: Sorry IgorT, when I said diodes in my previous post I was referring to laser diodes instead. Sorry for the confusion .


----------



## MatajumotorS

MatajumotorS said:


> I did get open can LD from LiteON LH-20A1P it is 20x.
> At 200mA it gets little warm after 5min in Axiz module. Had not tested it at higer rates. But it seems to me higer power than my previous LD with closed can from 16x, and it runs Mutch cooler.
> 
> Question:
> Do someone get some artifacts in LD beam of theese diodes? It is second one that i got. With optics there is some kind of "wings" line like in beam, well seen at 2-10m distance. Without the optic beam patern is not soft oval linear, but there is some kind of lines on sides of oval, causing the "wings". Will post pictures on monday.
> 
> Someone seen something like that?


 
Here are the pictures.
The LD from LiteOn LH-20A1P




http://www.bildez.lv/bildes/matajumotors/laser/orig/1193666321.jpg

Beam with no optic




http://www.bildez.lv/bildes/matajumotors/laser/orig/1193666323.jpg
Do You see the lines? This is white A4 paper under the ruller (ruller used to focus the camera..)

And beam with optics at 5 meter distance




http://www.bildez.lv/bildes/matajumotors/laser/orig/1193666325.jpg

What do you think about that?
IR LD has same "wings" in beam (with other optic)
Optic is not involved, because with other LD's witch has no lines in beam - has no "wings".


----------



## IgorT

VaThInK said:


> My TEC is rated at 15V and I was supplying 12V to it. In your case you could use a series of power diodes to drop the voltage down or better yet use a voltage regulator.


With just 2 diodes in series i'd get just about the right voltage for my TEC, 1.8V... I'd rather have it slightly "underdriven" than "overdriven".. It's very good at cooling as it is.



VaThInK said:


> 5V is safe though to use with laser diodes. I always power mine with 5V and in fact commercially made ones usually use 5V anyway.


So when you are talking about how many mA's is going through a LD you mean at 5V?

This, of course is a completely different story.. Since my power supply is 3V i could let more current through without worying about killing it...
I think i'll set mine to 300mA. I already tested it at 280 with no problems..


Otherwise i know how voltage regulators work. I often use them in devices i design for work. I have to develope all kinds of (sometimes) weird devices, so i know my way around electronics.

I just don't know much about lasers yet. The info i need is about LDs..



VaThInK said:


> The Sony 16x LD I mentioned is not the ones from GB as they're closed can. I had a Sony 16x drive that uses open can just like with Pioneer 112D. With the GB LDs 150mA ~ 200mA is good.


Is this 150mA ~ 200mA at 5V? This is what i need to know.

The power going to the LD would then be greater, than at the same current but lower voltage... To get a similiar result i could then raise the current to get approx the same power going into the LD. (or rather a little less for longer life)

Thanks!

Igor


----------



## VaThInK

IgorT said:


> Is this 150mA ~ 200mA at 5V? This is what i need to know.
> 
> The power going to the LD would then be greater, than at the same current but lower voltage... To get a similiar result i could then raise the current to get approx the same power going into the LD. (or rather a little less for longer life)
> 
> Thanks!
> 
> Igor



Yes it's at 5V. As far as I know LDs will clamp this voltage to whatever they require (3V for instance and not eating the whole 5V). So you are gonna end up with the same wattage just like if you are using 3V power source.

Yeah I figured you would have strong knowledge about voltage regulators. I made that post simply to help clarify your post below.



IgorT said:


> You misunderstood me.. Voltage INTO the LM317 is 6V. Once it gets to the LD it's only 3V and the current is regulated.



Note: In the second quote you actually said that the LD is only going to consume 3V (output from LM317 isn't going to be 3V, more like a bit <6V), but then in the first quote you said "The power going to the LD would then be greater".


----------



## Phenol

Hello, I am new to this forum, new to harvesting laser LEDs from DVD burners as well. 
Recently I got a Lite-on LH-20A1P drive and pulled both leds out. The second thing I felt like I must do was construct a current source based on an op amp and a darlington pnp transistor. Since most such circuits require that the LED's anode be connected to the positive rail thus putting +Ucc to the metal case + heatsink if present, I wanted to redesign it so that the LED is in common cathode configuration and all metal parts be at ground potential. I did manage to come up with a working solution pumping 150mA thru the red LED, the only drawback being that the stability of the current setting is dependent on the stability of the power supply. As such I used a 7805 linear regulator which proved decent in this respect...
The key moment (which killed the infrared led obtained from that same drive) was that a frequency compensation cap on one of the op amp inputs caused a few microsecond-long current overshoot /spike/ during power-up that obviously exceeded the maximum optical power density this LED's facet could handle, thus resulting in what is known as COD /catastrophic optical destruction/. The junction still worked ok, as the forward drop across it remained as it used to be before facet's demise /about 2 volts for the infrared led/. This means that, with fair heat dissipation, the junction may survive applying too much current, but the facet could be damaged in an instant if the 'hyper' power is maintained long enough. If you go through various datasheets of laser leds in this power range, you will notice that the pulse output power is as much as 3 times higher than the specified CW, but for pulse width <30ns and duty cycle <35% . Anything exceeding these values is likely to casue premature facet disruption... 
I corrected this annoying issue and, just to further smooth-out eventual transients, i connected a 1uF ceramic cap in parralel with the RED led. The scope verifies that the current ramps up gradually now.
As I have no idea what the specs of my red 'gem' are, I'm reluctant to run it much higher than 150mA. Even at that current, using a lens and a body from a $1 key-chain pointer, it is able to ignite matches in a second and punch a hole through a black floppy disk at a distance of 10 cm in less than a minute with a well focused beam.
A well-desined ARC lens will yield even more power and focusing precision. Some of those chinese cheapos never quite managed to focus in a well-defined spot without many side artefacts... A good source is Roithner, Austria. They ship collimator lenses in any quantity. 
Igor, I saw the photo of your 'blaster' and I noticed that the beam aperture is somewhat narrow. I used a similar set-up for my experiments and I discovered that the 'burning efficiency' increased when I increased the diameter of the aperture on the focusing nut. Pehaps a small circular aperture makes the projection more dot-like, as opposed to the 'bar-like' spot produced by most low-power leds...however this may effectively prevent some of the 'burning power' from escaping the aperture.
I will soon be buying a 20x LG drive. Wonder what the LEDs are going to be like. I am beginning to want a closed-can specimen for the sake of reliability. Open-can leds may dissipate heat better, but are susceptible to mechanical damage and environmental contaminants...
My goal now is to find good lenses. I bought all key-chain lasers in my town and only one or two had satisfactory lenses without much scratches and other frightening optical defects......


----------



## laserblue

Where do you get the collimator lens?


----------



## Phenol

http://www.roithner-laser.com

Below is their response. Prices are available on their website.

Thank you for your inquiry.

The GS-7020-2C is in stock and the price is EUR 1,81 / pc.
Shipping and handling: EUR 15,-- by postmail (sometimes postmail is fast, sometimes it´s slow)
 EUR 30,-- by DPD (you should get the parcel within 3-5 working days)
 EUR 40,-- by FedEx (you should get it in 1-2 working days)

Payment: in advance by bank transfer

If you want to make an order I need your VAT#. Without that number VAT must be added.

Best regards,

Marion Matzner

ROITHNER LASERTECHNIK GmbH
Wiedner Hauptstrasse 76, Top 9/1 A-1040 Vienna, Austria
Tel.: +43-1-586 52 43 - 11
Fax: +43-1-586 52 43 44
e-mail: [email protected]
http://www.roithner-laser.com


----------



## IgorT

VaThInK said:


> Note: In the second quote you actually said that the LD is only going to consume 3V (output from LM317 isn't going to be 3V, more like a bit <6V), but then in the first quote you said "The power going to the LD would then be greater".


 

BTW: I was talking about my LD in comparison to yours.. Mine gets 3V, yours gets >5V. The power is therefor greater at the same current.. (P=U*I)


Besides, it seems i confused your circuit with the Daedal's driver circuit (from laserpointerforums), which is not using a low drop out regulator, and has a voltage drop of almost 3V in it..

Sorry for the confusion...


EDIT: In this case i would like to see the circuit you're using.. Is it posted somewhere?


----------



## Phenol

MatajumotorS,

I obtained absolutely the same beam profiles, esp the uncollimated one, especially the ragged edges using that same LED at 150mA


----------



## IgorT

MatajumotorS said:


> IR LD has same "wings" in beam (with other optic)


 
I was wondering, how you view the IR LD's beam? With a CCD camera?



MatajumotorS said:


> Optic is not involved, because with other LD's witch has no lines in beam - has no "wings".


 
A very intriguing pattern.. I like it actually, but i know it probably bothers you, cos you want all of the light in one single point..


I have exectly the oposite problem. Without optics the light from the LD is the usual nice oval shape..

With the optics i get these weird (star like) "lines" going away from the point on the wall, and if i turn the laser the "lines" turn with it.

It this spread pattern usual for a narrow collimated beam (2mm diameter)?

I'll attach a pic..







Unfortunatelly i didn't manage to get the focus right, so the spot looks much larger than it actually is, while the "lines" are much longer, like 500mm dia at 5m...

This is not a reflection from the spot, cos it turns with the laser and it get's wider, the further away the wall is, while the spot remains the same size (2mm).

Is this normal, or is my lense messed up?


----------



## IgorT

Phenol said:


> As I have no idea what the specs of my red 'gem' are, I'm reluctant to run it much higher than 150mA. Even at that current, using a lens and a body from a $1 key-chain pointer, it is able to ignite matches in a second and punch a hole through a black floppy disk at a distance of 10 cm in less than a minute with a well focused beam.
> A well-desined ARC lens will yield even more power and focusing precision. Some of those chinese cheapos never quite managed to focus in a well-defined spot without many side artefacts... A good source is Roithner, Austria. They ship collimator lenses in any quantity.


You seem to know A LOT about electronics in general and the lasers as well. I would just like to point out one thing... We call the laser diodes "LDs", so as not to mix them up with LEDs.. LED is Light Emmiting Diode, while LD is a Laser Diode.. I'm sure you already know all that, so please don't take this wrong. I just pointed it out, cos it could be confusing to a newbie..



Phenol said:


> Igor, I saw the photo of your 'blaster' and I noticed that the beam aperture is somewhat narrow. I used a similar set-up for my experiments and I discovered that the 'burning efficiency' increased when I increased the diameter of the aperture on the focusing nut. Pehaps a small circular aperture makes the projection more dot-like, as opposed to the 'bar-like' spot produced by most low-power leds...however this may effectively prevent some of the 'burning power' from escaping the aperture.


Thank you! I was also considering this as a cause of the problem (hole too small in diameter to allow all the light to get out)

I will make the hole bigger, since i have to mod that thing anyway. I messed up my calculations (distance between the LD and the lense).

This means i also have to make an indentation in the inside of the focusing nut, to be able to screw it in further and allow for better focusing. 

I'll also make the hole bigger now. Thanks for the hint!

BTW: Do you think this too small hole could also be the cause of the lines going away from the point on the wall (in my pic above)? Like reflections from the edges of the inside of the too small hole, for example? Well, i'll know for sure in a few minutes anyway... 



Phenol said:


> I will soon be buying a 20x LG drive. Wonder what the LEDs are going to be like. I am beginning to want a closed-can specimen for the sake of reliability. Open-can leds may dissipate heat better, but are susceptible to mechanical damage and environmental contaminants...
> My goal now is to find good lenses. I bought all key-chain lasers in my town and only one or two had satisfactory lenses without much scratches and other frightening optical defects......


Since my lense assembly is also from a cheap laser pointer, i'm afraid, this is the cause of many of my problems..

I just hope the AixiZ modules arrive soon.


----------



## Phenol

Igor,
I have tested like 7 lenses and each produced a unique pattern on the wall. Most of them, when slightly defocused, produce a not well-defined blurry spot with 'protuberances'. Only 2 were able to produce a tiny spot with distinct edges and very few dim side patterns. Ideally, you should obtain a single spot with nothing around it / haze.../. If i were you i would examine the lens for scratches and dust. try defocussing it until you project a fairly large spot on the wall, like 5cm across, and look for dark spots and non-uniformities.


----------



## IgorT

Phenol said:


> Igor,
> I have tested like 7 lenses and each produced a unique pattern on the wall. Most of them, when slightly defocused, produce a not well-defined blurry spot with 'protuberances'. Only 2 were able to produce a tiny spot with distinct edges and very few dim side patterns. Ideally, you should obtain a single spot with nothing around it / haze.../. If i were you i would examine the lens for scratches and dust. try defocussing it until you project a fairly large spot on the wall, like 5cm across, and look for dark spots and non-uniformities.


 
I thought so as well. But first i need to fix my focusing nut and make the hole bigger, to see if makes a difference.

BTW: I cleaned the lense with ethanol before putting it in. But i noticed something weird on it...

It has something that looks like the dried vapours of CA glue on it. It's a narrow line, but it might also be a cause of this..

The CA vapours definatelly didn't get there during my glueing, since the lense was nowhere close to the parts i was glueing together..

It also has a tiny scratch, which could have been my fault.


Thanks for the hints!

Igor


EDIT: I just tried what you suggested (making a wider spot on the wall) and noticed A LOT of disturbance in the beam.. This lense really sucks! And besides, where i live it's nearly impossible to get any kind of laser pointer at all. I just wish AixiZ would finally respond to my inquiry.. I made a payment, but still got no answer..


----------



## Phenol

IgorT said:


> EDIT: I just tried what you suggested (making a wider spot on the wall) and noticed A LOT of disturbance in the beam.. This lense really sucks! And besides, where i live it's nearly impossible to get any kind of laser pointer at all. I just wish AixiZ would finally respond to my inquiry.. I made a payment, but still got no answer..


 
I just want to lay my hands on a couple of those Roithner lenses. They also have anti-reflection coating.


----------



## IgorT

Phenol said:


> I just want to lay my hands on a couple of those Roithner lenses. They also have anti-reflection coating.


 
What is that good for? So the beam can not get back into the LD?


BTW: I just moded the focusing nut, and made the hole bigger, like you suggested.
Now it's not a round spot anymore, but at least more light is coming out..
The star pattern also decreased, so i believe it was related to this.
But this lense is really bad. I can not focus it into a small dot. Nothing works...

What is the usual diameter of the opening in front of the lense, for example in the AixiZ modules?

EDIT: Does anyone know the distance between the LD and the lense in the aixiz module? I have to put my lense very far away from the LD so i'm worried not all of the light is actually being focused in the first place...


----------



## Phenol

IgorT said:


> What is that good for? So the beam can not get back into the LD?
> 
> 
> BTW: I just moded the focusing nut, and made the hole bigger, like you suggested.
> Now it's not a round spot anymore, but at least more light is coming out..
> The star pattern also decreased, so i believe it was related to this.
> But this lense is really bad. I can not focus it into a small dot. Nothing works...
> 
> What is the usual diameter of the opening in front of the lense, for example in the AixiZ modules?


 
Anti-reflective coating does reduce beam reflection back to the LD. This could be useful when the built-in photodiode is implemented in an APC circuit for instance. Such coating would reduce eventual loop disturbances when the position of the lens is altered. In our case, we dont use that monitor photodiode for automatic power control /my LD doesnt even have one built-in/, so the only benefit would be the increased transmission of the lens/reduced reflection losses/, ie, more burning capability and cool "bluish" aspect of the lens when viewed at an oblique angle...

I have never seen AixiZ module. I have extracted the LD holder from an old not-so-cheap pointer. It accommodates standard collimating lenses. The adjustment is done with a nut that exposes as much as 80% of the area of the lens

Igor, perhaps the LD is not well-cenetred with respect to the lens....


----------



## IgorT

Phenol said:


> Igor, perhaps the LD is not well-cenetred with respect to the lens....


 
The centering was the hardest part of the entire process.. I took great care, to put it in the "perfect" spot. But i did try moving it around and not much changed, except for the worse...

80% of the lense exposed you say... I'm still far away from that... Damn, more drilling..


BTW: Do you know the approximate distance between the LD and the lense in your assembly?


----------



## Phenol

IgorT said:


> The centering was the hardest part of the entire process.. I took great care, to put it in the "perfect" spot. But i did try moving it around and not much changed, except for the worse...
> 
> 80% of the lense exposed you say... I'm still far away from that... Damn, more drilling..
> 
> 
> BTW: Do you know the approximate distance between the LD and the lense in your assembly?


 
Not really sure :duh2: about that... My LD came from a lite-on drive and it looks exactly like MatajumotorS's photos. Its base is flush with the holder. The rest with the chip pedestal protrudes inside the cavity of the holder as far as a standard closed-can 5.6mm LD would, I reckon... I will measure this as soon as I get home. Anyway, I have been able to achieve focusing from 8cm to ~infinity (well.... kinda) with any collimator i scavenged from those cheap pointers. In general, the farther from the LD the lens goes, the closer it focuses. My objective was to produce a focused dot some 10cm from the aperture and I achieved it with ease without having the lens pop out.


----------



## petah

laserblue said:


> Can anyone tell what is the type of laser diode in an LG-H10A dvd-burner?
> i'd like to dissect my dvd-burner but i'm not sure what to expect.


 

hey laserblue!!!!

the LG-H10A model uses a 16x LD, I have one mounted in a flashlight shape housing, It's doing just fine running @ 300ma - 3.4V . I use it in short duties though... but it's pretty powerfull, don't know the exact output power but I was told that it might be around 200mw when batteries are fresh, I feed it with rechargeable ones....
good luck with yours!!!


----------



## petah

IgorT

EDIT: Does anyone know the distance between the LD and the lense in the aixiz module? I have to put my lense very far away from the LD so i'm worried not all of the light is actually being focused in the first place... [/quote]


Hi mate, 
the distance between the LD and the lens in my AixiZ module is something like 5mm or even less, pretty close!


----------



## petah

....


----------



## VaThInK

IgorT said:


> BTW: I was talking about my LD in comparison to yours.. Mine gets 3V, yours gets >5V. The power is therefor greater at the same current.. (P=U*I)
> 
> 
> Besides, it seems i confused your circuit with the Daedal's driver circuit (from laserpointerforums), which is not using a low drop out regulator, and has a voltage drop of almost 3V in it..
> 
> Sorry for the confusion...
> 
> 
> EDIT: In this case i would like to see the circuit you're using.. Is it posted somewhere?



Ah I see what you're trying to say. However, as I said before, my LD only eats ~3V and not the whole 5V even though I supply 5V to it. So the wattage would still be the same not greater than yours. Try it if you don't believe me :naughty:.

I believe Daedal's circuit uses LM317 and its voltage drop is around 1.2V not 3V. His circuit uses 2x LM317 to regulate current and voltage. That's why its outputting at 3V.

Hope this clear things out.

EDIT: Btw, I use Die4Drive for each LDs because I need them to be modulated for laser show. This LD driver gives out around 4.5V with 5V input due to voltage drop. For testing purposes I normally just use the 5V rail from PC PSU with 25W wire wound potentiometer in series to limit the current.


----------



## IgorT

petah said:


> Hi mate,
> the distance between the LD and the lens in my AixiZ module is something like 5mm or even less, pretty close!


 
Thanks..

This means my lense totaly sucks... It must have a totaly different dioptry.. Cos i think my distance is bigger, so a lot of the light gets lost before it even enters the lense.. 

No wonder it cant burn anything..


BTW: While i was mowing the lawn i left the laser on in my pocket for 20 minutes by mistake. I even thought "did i leave it on" but didn't check...

When i found it was on, i immediatelly checked for the temperature. I opened the enclosure and measured different spots, but nowhere was the temp greater than 35 degrees centigrade.. And this is from driving it at 200mA..

So at least my heatsinks work.. Anyone know the safe operating temperatures for these LDs?


BTW: Did you order your module from aixiz directly or dealextreeme? Is aixiz reliable? (i ordered directly, but got no reply)


----------



## IgorT

I have to correct myself..

I managed to focus the beam to a very narrow spot at 25 cm and put a piece of paper in front of it (that i painted black first of course).

It made a hole clean through.. I do have a burning laser! Even with the cheap puny lense..

I can imagine it will get even better with the aixiz housing.. I can hardly wait!

Unfortunatelly there are no matches or baloons in the house..


----------



## IgorT

VaThInK said:


> Ah I see what you're trying to say. However, as I said before, my LD only eats ~3V and not the whole 5V even though I supply 5V to it. So the wattage would still be the same not greater than yours. Try it if you don't believe me :naughty:.


I did try it, when testing this LD. Initially i limited the current to 200mA on my lab PSU. Then i raised the voltage to raise the power, but since the current was limited, the voltage stayed the same.. Then i allowed a little more current, and checked the voltage and it went to 4.2V (from 3.6V in the beginning) Only this way the current was able to go to 280mA (without removing or changing the resistor).

So if you raise the voltage, the current also raises (I= U/R), and so does the power (P=U*I), just like with any other electric components. Of course all this only applies when driving the LD directly, without any circuitry..

With a dual LM317 circuit it is possible to regulate the voltage and then the current, to make it constant, no matter what you feed into the circuit (within limits of course), if this is what you meant..



VaThInK said:


> I believe Daedal's circuit uses LM317 and its voltage drop is around 1.2V not 3V. His circuit uses 2x LM317 to regulate current and voltage. That's why its outputting at 3V.


Quite possibly, but that has to be a different circuit. The one i meant uses only one LM317 and i was told it has a voltage drop of 3V. It is possible the person who explained it to me didn't understand it fully tho..



VaThInK said:


> EDIT: Btw, I use Die4Drive for each LDs because I need them to be modulated for laser show. This LD driver gives out around 4.5V with 5V input due to voltage drop. For testing purposes I normally just use the 5V rail from PC PSU with 25W wire wound potentiometer in series to limit the current.


Which driver is this? Never heard of it before. Can you point me to it perhaps?


----------



## Phenol

IgorT said:


> I did try it, when testing this LD. Initially i limited the current to 200mA on my lab PSU. Then i raised the voltage to raise the power, but since the current was limited, the voltage stayed the same.. Then i allowed a little more current, and checked the voltage and it went to 4.2V (from 3.6V in the beginning) Only this way the current was able to go to 280mA (without removing or changing the resistor).
> 
> So if you raise the voltage, the current also raises (I= U/R), and so does the power (P=U*I), just like with any other electric components. Of course all this only applies when driving the LD directly, without any circuitry..
> 
> With a dual LM317 circuit it is possible to regulate the voltage and then the current, to make it constant, no matter what you feed into the circuit (within limits of course), if this is what you meant..
> 
> 
> Quite possibly, but that has to be a different circuit. The one i meant uses only one LM317 and i was told it has a voltage drop of 3V. It is possible the person who explained it to me didn't understand it fully tho..
> 
> 
> Which driver is this? Never heard of it before. Can you point me to it perhaps?


 
http://www.die4laser.com/dvd-rec/Die4Drive_files/Die4DriveRev1-2.pdf

mine is similar. ive totally 'flipped it around' as i didnt want to have the LD case hooked to +5V. this one uses a fet as a current sinking component, this way the compliance range is wider compared to a BJT.


----------



## VaThInK

Yeah, that behavior sounds right IgorT. My LDs consume 3V @ 380mA and the voltage will only start to increase slowly if I increase the current. This is when I was only using a resistor in series with the LD. They won't get >3V if I don't overdriven them really hard. This is probably due to different LD internal resistance characteristics. Below is the circuit that I'm using when I properly run my setup for laser light show.



Phenol said:


> http://www.die4laser.com/dvd-rec/Die4Drive_files/Die4DriveRev1-2.pdf
> 
> mine is similar. ive totally 'flipped it around' as i didnt want to have the LD case hooked to +5V. this one uses a fet as a current sinking component, this way the compliance range is wider compared to a BJT.



Care to explain what you mean by flipping it around :thinking:? Isn't the LD case from DVD drives actually ground?


----------



## Phenol

VaThInK said:


> Yeah, that behavior sounds right IgorT. My LDs consume 3V @ 380mA and the voltage will only start to increase slowly if I increase the current. This is when I was only using a resistor in series with the LD. They won't get >3V if I don't overdriven them really hard. This is probably due to different LD internal resistance characteristics. Below is the circuit that I'm using when I properly run my setup for laser light show.
> 
> 
> 
> Care to explain what you mean by flipping it around :thinking:? Isn't the LD case from DVD drives actually ground?


 
I reworked the entire circuit so that the cathode of the LD /its case/ is connected to GND and current is pumped by the transistor from 'above' , i.e., its anode, as opposed to the die4laser circuit in which LD's cathode must be connected to the drain electrode of Q1. The main issue this arrangement poses is that you actually end up having non-ground potential on the case of the LD and its heatsink respectively. I run the circuit off a lab PSU whose negative terminal is connected to its metal case. In this respect, any exposed massive metallic parts at some potential other than ground with respect to PSU's ground/chassis/PC/Scope........are subjected to short-circuit events if accidentally touched to any of these.
The next disadvantage /not really applicable in the proposed circuit/ of not having the LD case hooked to electrical GND is the fact that its case along with the heatsink present a fairly large parasitic capacitance connected to the active element. As this would not be an issue for you laser show experiments using this driver where the beam is likely to be modulated with fairly low frequencies where a couple of picofarads more mean nothing, in a high-speed application /with very short pulses in the nanosecond range/ they may prove critical...not to mention the amount of RFI a big metal case connected to a 'live' high freq terminal would radiate.


----------



## VaThInK

Ah I see what you mean. So you're using P channel FET instead I guess for the reworked circuit. I actually killed my LD once by accident as the result of the ground not being on the same level as the LD cathode. Thanks mate.


----------



## Phenol

VaThInK said:


> Ah I see what you mean. So you're using P channel FET instead I guess for the reworked circuit. I actually killed my LD once by accident as the result of the ground not being on the same level as the LD cathode. Thanks mate.


 
I'm not using a FET, i am using a pnp darlington instead. A P-channel FET may also work, I just didn't have one at hand. I have the basic schematic of what I have done, but it will obviously remain in secrecy for now, as I can't post attachments :thinking:


----------



## IgorT

Phenol said:


> I'm not using a FET, i am using a pnp darlington instead. A P-channel FET may also work, I just didn't have one at hand. I have the basic schematic of what I have done, but it will obviously remain in secrecy for now, as I can't post attachments :thinking:


 
You can post attachments on laserpointerforums and then link them from here..

That's how i managed to put up all of my pics..


----------



## petah

IgorT


This means my lense totaly sucks... It must have a totaly different dioptry.. Cos i think my distance is bigger, so a lot of the light gets lost before it even enters the lense.. 

No wonder it cant burn anything..
BTW: Did you order your module from aixiz directly or dealextreeme? Is aixiz reliable? (i ordered directly, but got no reply)[/quote]



....yeah mate. you're wasting lots of red that way..
I ordered my module from DealExtreme and took like 3 weeks to arrive, it's pretty much for the job, it's metal made, good for spreading heat and it's adjustable, I feed my 2 LDs with 300ma - 3.4V (one is 16x and one 18x, both seem to have the same output power) when focused I can light a match 5 feet away and pop ballons @ 20 feet....





When i found it was on, i immediatelly checked for the temperature. I opened the enclosure and measured different spots, but nowhere was the temp greater than 35 degrees centigrade.. And this is from driving it at 200mA..

So at least my heatsinks work.. Anyone know the safe operating temperatures for these LDs?




.. 35ºC it's a pretty safe temperature, as long as you stay under 70ºC you'll be safe but remember, the hotter is the LD the weaker it gets!

PS: I've read that before in this thread... and seems I have the same problem with my laser, there's a lot of wasting red spreading out from the main beam (around the dot) don't know what it is... cleaned the lens but nothing.... looks like I'm losing lots of power that way.. anyone has any idea how to fix this?


----------



## Phenol

IgorT said:


> You can post attachments on laserpointerforums and then link them from here..
> 
> That's how i managed to put up all of my pics..


 
:twothumbs

The current that flows thru the LD is calculated as follows:
I=[Ucc(5V)-Ur(R1+R2)/R2]/Rsense
In my case R1=10k, R2=15k, Rsense=1.8ohms
Ucc must be stabilized because the stability of I is proportional to its own.
The op amp's output must be able to swing within power supply rails. CMOS opamps have rail-to-rail capable outputs.
Ucc bypass caps not shown for clarity, however, they must be present for stability
Whatever we do, we must make sure that there are no current spikes exceeding the maximum values for the specific LD during transient events, such as toggling the circuit on/off and applying modulation...


----------



## Phenol

IgorT said:


> I have to correct myself..
> 
> I managed to focus the beam to a very narrow spot at 25 cm and put a piece of paper in front of it (that i painted black first of course).
> 
> It made a hole clean through.. I do have a burning laser! Even with the cheap puny lense..
> 
> I can imagine it will get even better with the aixiz housing.. I can hardly wait!
> 
> Unfortunatelly there are no matches or baloons in the house..


 
Igor, for your reference, this is a frontal view of my 'beastie'. As you can see, most of the collimator 'eye' :huh: is exposed. It is a 7x3.29mm lens.
Below is a copper sheet that i got from the pick-up module. The LD housing is glued with some epoxy resin glue to the sheet. Ive also added some thermoconductive paste between the brass housing and the sheet. It is a miserable small heatsink, but at 150mA it runs pretty cool... not exceeding 40 degrees C @ 20C ambient temperature .


----------



## IgorT

petah said:


> ....yeah mate. you're wasting lots of red that way..


Unfortunatelly there is nothing i can do right now.. but as it is, it's already a burning laser...



petah said:


> I ordered my module from DealExtreme and took like 3 weeks to arrive, it's pretty much for the job, it's metal made, good for spreading heat and it's adjustable, I feed my 2 LDs with 300ma - 3.4V (one is 16x and one 18x, both seem to have the same output power) when focused I can light a match 5 feet away and pop ballons @ 20 feet....


3 weeks? Oh well. I'll just have to wait i guess.

I hope when i get them, mine can also pop a baloon at 20 feet.. 




petah said:


> .. 35ºC it's a pretty safe temperature, as long as you stay under 70ºC you'll be safe but remember, the hotter is the LD the weaker it gets!


I know that.. But it's also good to know the safe limits.. And if below 70ºC is considered safe, then i'm VERY happy with my heatsinks! 



petah said:


> PS: I've read that before in this thread... and seems I have the same problem with my laser, there's a lot of wasting red spreading out from the main beam (around the dot) don't know what it is... cleaned the lens but nothing.... loos like I'm losting lots of power that way.. anyone has any idea how to fix this?


I have this same problem.. Or at least similiar.. I was hoping the aixiz housings and lenses would fix this problem..

With mine it looks like that star shaped thing i posted above.. It's wasted power.  One thing tho.. After i made the hole in the focusing nut bigger, this star became smaller... 

So i'm thinkin, what if it's reflections from the inside of the hole?


----------



## IgorT

Phenol said:


> Igor, for your reference, this is a frontal view of my 'beastie'. As you can see, most of the collimator 'eye' :huh: is exposed. It is a 7x3.29mm lens.
> Below is a copper sheet that i got from the pick-up module. The LD housing is glued with some epoxy resin glue to the sheet. Ive also added some thermoconductive paste between the brass housing and the sheet. It is a miserable small heatsink, but at 150mA it runs pretty cool... not exceeding 40 degrees C @ 20C ambient temperature .


 
Very nice.. The optics assembly was scavanged from a cheap laser pointer?

It is very similiar to mine, but has a larger opening, and if i understand you correctly, it has a hole in which you stick your LD, right?

Well, mine didn't.. The laser in the cheap pointer i scavanged, was just a flat LD chip soldered on a piece of metal, and it didn't survive the extraction process..

And since it didn't have the LD hole, i had to play with it A LOT before i got it centered.. In the end i glued the LD to the heatsinks and the heatsinks to the lense assembly, and all of this to a piece of plastic, so it wouldn't fall apart, and stay centered..

A piece of metal would be better, cos it would help with heat sinking and i could even mount a peltier to it..

But that's for my next project.. Right now my laser works perfectly, considering the conditions.. I feed it more current (200mA) but it never exceeds 35C.. This is becouse my heatsinks have fins, (more surface area) and can give off some heat to the surrounding air. Since you have everything on a metal plate, as it is, you could just glue some heatsinks with fins to this metal plate and would then be able to feed it more current, while it would actually get less warm.


Anyway, thanks to everyone for the encouragement, the help and suggestions!


Igor


P.S. *Phenol*: I see you found a way of posting attachments.. Nicely done..


----------



## Phenol

IgorT said:


> Very nice.. The optics assembly was scavanged from a cheap laser pointer?
> 
> It is very similiar to mine, but has a larger opening, and if i understand you correctly, it has a hole in which you stick your LD, right?
> 
> Well, mine didn't.. The laser in the cheap pointer i scavanged, was just a flat LD chip soldered on a piece of metal, and it didn't survive the extraction process..
> 
> And since it didn't have the LD hole, i had to play with it A LOT before i got it centered.. In the end i glued the LD to the heatsinks and the heatsinks to the lense assembly, and all of this to a piece of plastic, so it wouldn't fall apart, and stay centered..
> 
> A piece of metal would be better, cos it would help with heat sinking and i could even mount a peltier to it..
> 
> But that's for my next project.. Right now my laser works perfectly, considering the conditions.. I feed it more current (200mA) but it never exceeds 35C.. This is becouse my heatsinks have fins, (more surface area) and can give off some heat to the surrounding air. Since you have everything on a metal plate, as it is, you could just glue some heatsinks with fins to this metal plate and would then be able to feed it more current, while it would actually get less warm.
> 
> 
> Anyway, thanks to everyone for the encouragement, the help and suggestions!
> 
> 
> Igor
> 
> 
> P.S. *Phenol*: I see you found a way of posting attachments.. Nicely done..



The brass thing was scavenged from a dead pointer I bought years ago for some $10. It housed a standard 5.6mm LD and had already died when I decided to resurrect bits and pieces of it. The lens came from a really cheap pointer. I will soon be ordering coated lenses from Roithner. The coating is centered at 670nm+-20nm. I m really hoping for good burning capability :candle: under safe operating conditions


----------



## IgorT

Phenol said:


>


 
BTW: Now that you posted your pics on laserpointerforums, without any explanation, people started asking questions about your driver.. 

I took the liberty of pasting your explanation of the circuit there, so they know what it's about...


----------



## Phenol

IgorT said:


> BTW: Now that you posted your pics on laserpointerforums, without any explanation, people started asking questions about your driver..
> 
> I took the liberty of pasting your explanation of the circuit there, so they know what it's about...


----------



## petah

IgorT

When i found it was on, i immediatelly checked for the temperature. I opened the enclosure and measured different spots, but nowhere was the temp greater than 35 degrees centigrade.. And this is from driving it at 200mA..

So at least my heatsinks work.. Anyone know the safe operating temperatures for these LDs?


Hey buddy!! one thing....
if you want your laser for burning purpose "like me" and if you have a good heat sink "like mine"... why don't you push it a little harder... 200ma sounds a little low... as I said before I run my 2 diodes @ 300ma and no problem at all... 
.. and updating my records..
I just got my batteries full "recharged" and just lit a match 7 feet away... at this distance is kinda hard to focus the beam into a tiny spot, and it took some time though.... here is how it works...

distance <5 feet = matches ignite almost immediately - less than a second
at 6 feet = matches ignite in 2 seconds
at 7 feet = take more than 5 seconds

this running at 300ma, for both 16x and 18x LDs "LG GSA-10a and LG GSA-50n"

Now I'm looking for a Pioneer 112D, I wanna push it even harder... something like 400ma, yet our mate Vathink has had nice results with this one....



think about it and good luck!!!


----------



## Gazoo

I posted the following at LPF's but thought I would post it here so you all can see TEC cooling is a major plus:

Heatsinking is enough for portables running short duty cycles, but as hard as we push these diodes in our DIY labbys, TEC or fan cooling is almost a must. Personally I like the TEC route much better. 

I received a new set of peltiers today and recently received my LPM-1. I have always been very curious as to what effect a TEC has, and I found out as soon as the glue dried.. 

I am running an open can diode with ~400ma's. I normally was able to get ~230mw's out of it running it with some cooling. The reason I say some is because I did not have my previous peltier glued perfectly flat. 

Anyway, I constructed a new TEC and was able to get an additional 15mw's out of the diode. I might have been able to get a little more had I applied more current to the peltier, but I did not want to risk it on account of condensation. 

Out of curiosity, I shut off the TEC, and the power of the diode dropped as it heated up. I let it get quite warm and the power had dropped to 170mw's. TEC cooling is a huge plus.... :thumbsup:

NOTE, this diode did come out of the 112D and I have run it with 500ma's, the power measured at ~270mw's..

Following are a couple of pics of mine..I know it is ugly..lol...I need to rework the whole circuit board but it does a damn good job.


----------



## IgorT

petah said:


> Hey buddy!! one thing....
> if you want your laser for burning purpose "like me" and if you have a good heat sink "like mine"... why don't you push it a little harder... 200ma sounds a little low... as I said before I run my 2 diodes @ 300ma and no problem at all...


And your only heatsinking is an aixiz housing?

I do believe my LD could do 300mA with no problems, it already did 280 while mounted on a larger heatsink.. But at this point, i would have to change my circuit, to drive it any "harder".. Actually, just change one resistor, but for now, i'm just happy i have a pretty good, working laser, with a very visible beam..

Since i'm going to a different city (to my girlfriend) for the next few days, i just want the laser to work through this time, so i can show it to all the interested people.

Besides, i bought a few matches today, for one single purpose and i can light them if i want.. But i have to make a black spot on their head first..

My biggest problem right now is lousy optics.. I don't want to push my laser harder, while some (or even most) of the power is getting lost due to bad optics..

Once i get the aixiz housings however, i will definatelly try 300mA, and if it turns out to start getting to warm, i still have a small TEC waiting just for this purpose... 




petah said:


> .. and updating my records..
> I just got my batteries full "recharged" and just lit a match 7 feet away... at this distance is kinda hard to focus the beam into a tiny spot, and it took some time though.... here is how it works...
> 
> distance <5 feet = matches ignite almost immediately - less than a second
> at 6 feet = matches ignite in 2 seconds
> at 7 feet = take more than 5 seconds
> 
> this running at 300ma, for both 16x and 18x LDs "LG GSA-10a and LG GSA-50n"


Nice results if you ask me.. Are these matches red? Or are they darker / you put a black spot on them??

But my beam is very hard to focus at any more than maybe 2 feet, due to the lousy optics, so i'll let my little laser as it is for now. I don't see the point of driving it harder as long as my lense is the source of all my problems.. First i want to see what it can do with proper optics and THEN drive it harder...

But, as i said, once i get the aixiz modules, i'll try 300mA (or more with active cooling).. (i still have a few LDs left, and more are soon coming from my free source )

Right now, for a while, i'm just gonna be happy i have a working (and burrning) laser..


But you can be sure, i'll let you know when i make it better and stronger. With details of course... 


*EDIT*: Actually i can already give you a description of my next laser project right now.. You've seen my small laser enclosure, right? Well, i intend to make a hole in the next one, big enough to mount my small peltier through it (15x15mm) The LD assembly will be glued onto a copper plate, this will be mounted on the cold side of the peltier and outside of the plastic enclosure, i will attach a heatsink with fins to the hot side of the peltier...

Then i'll run the LD at 300mA and measure everything going on.. Then i might try 350... Maybe more (if i add a small fan to the peltiers heatsink).. By that time i should have quite a large collection of these free (but obviously strong) LDs.. So i'll test it to it's limits, and in case it dies, i'll know what not to do with the next one..

Oh, both the LD and the peltier will be running off the same power source - a small hobby grade LiPo inside the box.. I have a few stronger ones in case i need them, that would still fit the enclosure.


The other plan is to make some holes into the enclosure i have right now, directly beneath the fins of my heatsinks, and use a tiny pager motor with a tinly helicopter tail rotor, to provide some airflow.. I believe i could then run the current "phaser" at 300mA without any problems..


*EDIT EDIT*: From all this it should be obvious, what i want: As strong as possible AND as small as possible, at the same time..  Wish me luck!


----------



## IgorT

I have to correct myself..

I just measured the current and saw that my LD is eating around 300mA when the LiPo is full.. I wanted to change it a little, but after seeing this, i'm even happier with it..


So basically all i need now are those better lenses.. Why won't AixiZ reply to me??? 


*EDIT*: I was wrong about the temperature.. I made a assumption nothing changed in my circuit, as i removed the pot, (that was only there for setting up, as it can't survive such currents for long).. Since the pot was at it's lowest setting and i measured allmost no difference with or without it, i assumed it wasn't doing anything.. but it was obviously enough, to reduce the current from 300mA to around 200mA..

Now it heats up much quicker (in only a minute or two) to 45°C.. I don't want to let it on for very long, since there is no way to measure the actual temperature of the LD.

I think i'll add 0.3 - 0.5 Ohm series resistance.. I don't want to kill (or damage) it too soon... Or maybe i should keep it as it is and only make the duty cycles shorter? Tough decision...


*EDIT EDIT*: Guys, i was wondering.. How does one convince a cat to wear protection goggles?

You all know how cats like to chase the dots from laser pointers.. Well, what happens when these lasers become 200x stronger? Since now the entire beam is visible, my cat lost the interest in the dot.. Now she's after the beam itself. She climbed on the cupboard and tried to take it out of the air.. When i looked at her, her eyes were glowing red.. I'm a little worried, altho she didn't look directly into the beam... But still, are there any special goggles for cats? 

BTW: I checked and she's ok.. I'm asking for the next time...


----------



## Phenol

IgorT said:


> I have to correct myself..
> 
> I just measured the current and saw that my LD is eating around 300mA when the LiPo is full.. I wanted to change it a little, but after seeing this, i'm even happier with it..
> 
> 
> So basically all i need now are those better lenses.. Why won't AixiZ reply to me???
> 
> 
> *EDIT*: I was wrong about the temperature.. I made a assumption nothing changed in my circuit, as i removed the pot, (that was only there for setting up, as it can't survive such currents for long).. Since the pot was at it's lowest setting and i measured allmost no difference with or without it, i assumed it wasn't doing anything.. but it was obviously enough, to reduce the current from 300mA to around 200mA..
> 
> Now it heats up much quicker (in only a minute or two) to 45°C.. I don't want to let it on for very long, since there is no way to measure the actual temperature of the LD.
> 
> I think i'll add 0.3 - 0.5 Ohm series resistance.. I don't want to kill (or damage) it too soon... Or maybe i should keep it as it is and only make the duty cycles shorter? Tough decision...


 
These should be able to work safely at as many as 70-75°C. The inner ambience of a fast-speed DVD writer isnt what we would call 'amiable'...Runnung it at higher temps does indeed degrade performance and life expectancy, though... but what the heck, u have got a source of free LDs. My motto now is reliability, efficiency, longevity. I want it to outlast its owner. :huh:


----------



## IgorT

Gazoo said:


> Out of curiosity, I shut off the TEC, and the power of the diode dropped as it heated up. I let it get quite warm and the power had dropped to 170mw's. TEC cooling is a huge plus.... :thumbsup:


 
When you say you let it get quite warm, do you have an idea of how warm it was? Did you feel this warmth at the block of metal you have it mounted in or at the LD istelf?


I just tested my laser at 300mA for 4 minutes and the temperature got to 40° on the heatsinks..

At the LD itself it must be higher, but there is no way to tell. It can't be much higher tho, since there is not that much metal attached to it..

Should i be worried about lower power output with the LD at 45-55°C?

Or are the temperatures at which the power starts dropping higher than that?

I had a feeling it is putting out less light as time went by, but it could be a placebo... (me imagining the light going dimmer due to what i read here)

If i'm loosing power due to higher temperature at 300mA, i'd rather reduce the current a little, and get approx the same power with less curent and especially less stress for the LD.. What do you think?

Am i just worrying too much?


Thanks!


----------



## IgorT

Phenol said:


> These should be able to work safely at as many as 70-75°C. The inner ambience of a fast-speed DVD writer isnt what we would call 'amiable'...Runnung it at higher temps does indeed degrade performance and life expectancy, though... but what the heck, u have got a source of free LDs. My motto now is reliability, efficiency, longevity. I want it to outlast its owner. :huh:


 
I do have a free source, but it's not constant.. Sometimes i get three in a day and other times none for weeks..

So you think at, let's say 60°C the diode does not yet lose any power due to heat?

In that case i'll just let it as it is right now, running at 300mA. It's strong and i like it.. Besides it takes more than 4 minutes, for the temp to get that high in the first place.. By that time a few matches should be lit already.. 

Thank you for comforting me.. I should just enjoy it while it lasts..


----------



## Phenol

IgorT said:


> I do have a free source, but it's not constant.. Sometimes i get three in a day and other times none for weeks..
> 
> So you think at, let's say 60°C the diode does not yet lose any power due to heat?
> 
> In that case i'll just let it as it is right now, running at 300mA. It's strong and i like it.. Besides it takes more than 4 minutes, for the temp to get that high in the first place.. By that time a few matches should be lit already..
> 
> Thank you for comforting me.. I should just enjoy it while it lasts..


 
http://www.photonic-products.com/products/laserdiodes_visible/hitachi_visible_ds/hl6545mg.pdf


----------



## IgorT

Phenol said:


> http://www.photonic-products.com/products/laserdiodes_visible/hitachi_visible_ds/hl6545mg.pdf


 
Thank you again! A very interesting DataSheet..

While i'm driving my LD stronger than that datasheet specifies, my heat issue seems to be under controll..

I did some more tests and in "normal" use it never goes above 40°C..

The output is a very strong and visible beam, so i'll just be happy for now.. There's time (and LDs) for optimizing it later..

Now i can go to sleep without worrying my laser would die soon..


----------



## Gazoo

Igor,
By warm I mean borderline to being hot..but not so hot I could not keep my finger on the cube. But keep in mind that even though the cube alone helps to keep the diode cool, I have no way of measuring the actual temp of the diode or even the module.


----------



## IgorT

Gazoo said:


> Igor,
> By warm I mean borderline to being hot..but not so hot I could not keep my finger on the cube. But keep in mind that even though the cube alone helps to keep the diode cool, I have no way of measuring the actual temp of the diode or even the module.


 
I understand.. Since us humans percieve around 60°C as hot, i think this could be the temperature you felt.. The LD could have anywhere between 70° to 80°C at this point, since the cube seems quite big..

At this temperature, the output drop you described, is similiar to the one in the datasheet above..

Thanks for the info! It seems i really don't have anything to worry about..

Except for my cat that is...


----------



## petah

IgorT

And your only heatsinking is an aixiz housing?


... I created a "pool" around the aixiz module, my laser is mounted in a flashlight, and the module is immersed in water, insulated of course... so, the LD is stuck in the module and module disperses the heat in water..




Nice results if you ask me.. Are these matches red? Or are they darker / you put a black spot on them??


sometimes I have dark matches to work with... but they're kinda hard to find... so I get the red ones and rub some barbecue charcoal on the head and BINGO! nice black head matches...



*EDIT*: Actually i can already give you a description of my next laser project right now.. You've seen my small laser enclosure, right? Well, i intend to make a hole in the next one, big enough to mount my small peltier through it (15x15mm) The LD assembly will be glued onto a copper plate, this will be mounted on the cold side of the peltier and outside of the plastic enclosure, i will attach a heatsink with fins to the hot side of the peltier...

Then i'll run the LD at 300mA and measure everything going on.. Then i might try 350... Maybe more (if i add a small fan to the peltiers heatsink).. By that time i should have quite a large collection of these free (but obviously strong) LDs.. So i'll test it to it's limits, and in case it dies, i'll know what not to do with the next one..

Oh, both the LD and the peltier will be running off the same power source - a small hobby grade LiPo inside the box.. I have a few stronger ones in case i need them, that would still fit the enclosure.


The other plan is to make some holes into the enclosure i have right now, directly beneath the fins of my heatsinks, and use a tiny pager motor with a tinly helicopter tail rotor, to provide some airflow.. I believe i could then run the current "phaser" at 300mA without any problems..



nice job, I don't have any TEC... but I think I will be getting some soon....
when I put my hands on a pioneer 112D I wanna try it really hard... and would be nice to have some cooler working... like a peltier.

good luck mate!!!!


----------



## Phenol

IgorT said:


> Thanks for the info! It seems i really don't have anything to worry about..
> 
> Except for my cat that is...


 
LOL, you didn't laserblast you cat's fur head-on, did you?oo: If he is the black panther-like type of cat, you'd sure get an adequate uproarious reaction in a matter of minute


----------



## IgorT

Phenol said:


> LOL, you didn't laserblast you cat's fur head-on, did you?oo: If he is the black panther-like type of cat, you'd sure get an adequate uproarious reaction in a matter of minute


 
The laser was on my desk, pointed across the room.. I went along the beam, measuring if it's "perfectly" straight.. Then i returned to my desk to turn it off, only to see my cat trying to catch the beam... She was facing the laser, so the beam was very visible to her, and obviously very interesting..

I would NEVER point it at her on purpose.. I love her..

I'm thinking about buying some blue contact lenses for her.. I don't think i could get the goggles to stay on her for any amount of time.


----------



## IgorT

petah said:


> sometimes I have dark matches to work with... but they're kinda hard to find... so I get the red ones and rub some barbecue charcoal on the head and BINGO! nice black head matches...


So it's normal for the matches having to be black to get lit by a laser?

In this case, it seems my laser is working..



petah said:


> nice job, I don't have any TEC... but I think I will be getting some soon....
> when I put my hands on a pioneer 112D I wanna try it really hard... and would be nice to have some cooler working... like a peltier.


Peltiers are very nice things to have when playing with lasers..

And they're not even all that expensive.. Especially, since you don't even need a very big one for a LD. You just need to make sure you are dispersing the heat away from it's hot side and it's gonna do a very good job.. If you forget this, however (or don't disperse enough) it can make things worse..

Since it's a heat "pump", the more heat you remove on the hot side, the more heat it can pump away from the cold side..

The one i bought was the smallest one they had 15x15mm 4W.. I believe it's powerfull enough to make my LD go from 45°C to room temp., or lower (in which case i could drive the LD a little stronger).. If not, i'll buy a bigger peltier and it'll still fit in my small enclosure.. 


Good luck!


----------



## petah

IgorT

So it's normal for the matches having to be black to get lit by a laser?

In this case, it seems my laser is working..


yep mate, matches have to be dark "black is the best" you can't light a red head match with a red laser, or at least you won't do that easily, the reason why one thing is red is because it absorves any collor but red, it reflects the red....

Peltiers are very nice things to have when playing with lasers..

And they're not even all that expensive.. Especially, since you don't even need a very big one for a LD. You just need to make sure you are dispersing the heat away from it's hot side and it's gonna do a very good job.. If you forget this, however (or don't disperse enough) it can make things worse..


I know that buddy... and my duty cicles are short.... so I ain't worried about overheatin'.....


----------



## IgorT

petah said:


> the reason why one thing is red is because it absorves any collor but red, it reflects the red....


Yeah, i know.. That's how i found my helicopter's metal flybar when it was lost in grass. At first i was crawling around on my knees for half an hour in full daylight and then gave up..
Then, in the evening, i remembered, how i was explaining to a friend, why in red light, you only see things that reflect red.. So i picked up my red LED flashlight, scanned the lawn for 20 seconds and found the flybar, since the metal reflected the red, while i was able to see THROUGH the grass..  I was actually dissapointed at how fast i found it.. That's how interesting the effect was.



petah said:


> I know that buddy... and my duty cicles are short.... so I ain't worried about overheatin'.....


I'm sorry, i wasn't implying that you don't.. Just hoping the explanation might help someone sooner or later..

I also stopped worrying about the heat, after getting to know my laser a bit better and reading that datasheet.. Now i know it's eating 300mA when the LiPo is full and 230mA when it's almost empty.. In both cases it can ignite a match in less than a second, and the temperatures are not that bad.. I'm actually starting to like this LD, and would recommend it to others.. (Samsung TS-H552 v.B or v.U)


When you get the peltier, i would be very interested in it's specs, how you set it up and the temperatures you measure..


BTW: What do you use, to measure the temp? I use a non-contact IR thermometer, but it's only exact when pointed at something dark.. Luckily my heatsinks are black, but i painted everything else aswell, to be able to measure at different spots..


----------



## Phenol

IgorT said:


> BTW: What do you use, to measure the temp? I use a non-contact IR thermometer, but it's only exact when pointed at something dark.. Luckily my heatsinks are black, but i painted everything else aswell, to be able to measure at different spots..


 I use a K-type thermocouple. Most multimeters have a temperature function based on a thermocouple probe.


----------



## petah

IgorT said:


> Yeah, i know.. That's how i found my helicopter's metal flybar when it was lost in grass. At first i was crawling around on my knees for half an hour in full daylight and then gave up..
> Then, in the evening, i remembered, how i was explaining to a friend, why in red light, you only see things that reflect red.. So i picked up my red LED flashlight, scanned the lawn for 20 seconds and found the flybar, since the metal reflected the red, while i was able to see THROUGH the grass..  I was actually dissapointed at how fast i found it.. That's how interesting the effect was.
> 
> 
> I'm sorry, i wasn't implying that you don't.. Just hoping the explanation might help someone sooner or later..
> 
> I also stopped worrying about the heat, after getting to know my laser a bit better and reading that datasheet.. Now i know it's eating 300mA when the LiPo is full and 230mA when it's almost empty.. In both cases it can ignite a match in less than a second, and the temperatures are not that bad.. I'm actually starting to like this LD, and would recommend it to others.. (Samsung TS-H552 v.B or v.U)
> 
> 
> When you get the peltier, i would be very interested in it's specs, how you set it up and the temperatures you measure..
> 
> 
> BTW: What do you use, to measure the temp? I use a non-contact IR thermometer, but it's only exact when pointed at something dark.. Luckily my heatsinks are black, but i painted everything else aswell, to be able to measure at different spots..


 

It's OK buddy.. I got you!

and I use the same as you... a non-contact IR thermometer.


----------



## IgorT

BTW: Guys, how dangerous are reflections from these lasers, from dark surfaces?

I noticed, my laser makes quite a little light show while burning through a piece of black painted paper for example..

Even a floppy disk reflects a surprising amount of light..

Any thoughts on this?


----------



## Phenol

IgorT said:


> BTW: Guys, how dangerous are reflections from these lasers, from dark surfaces?
> 
> I noticed, my laser makes quite a little light show while burning through a piece of black painted paper for example..
> 
> Even a floppy disk reflects a surprising amount of light..
> 
> Any thoughts on this?


Yes, I have noticed that, too. While some plastics look black and mat, it is often times their texture that makes them diffuse reflectors. But when the hot dot melts a small spot, the surface underneath becomes glossy and reflective....
Do wear goggles. Specular reflections can be just as harmful, especially those from shiny polished metal objects...:mecry:


----------



## Kenom

You guys may wanna look in the gb section. I'm putting together a gb on custom laser barrels. check it out in the GB section of the marketplace.


----------



## Phenol

These are pictures of the emitting side of a chip-type LD/ found in cheap pointers/ magnified 500x. the first pic shows the LD pumped with ~1mA. It is not lasing yet.The pink surfce is the cleaved mirror facet with a scratch and speckles of contaminants. The second is the same thing with ambient lighting switched off. In the third one the LD is at about threshold current. Higher than that the webcamera became saturated. I'm temped to put a current spike thru this LD and literally see what happens


----------



## MatajumotorS

Just finished my DIY laser.






















Used parts:

Laser module
http://www.dealextreme.com/details.dx/sku.5914

Host
http://www.dealextreme.com/details.dx/sku.2089

Converter
http://www.dealextreme.com/details.dx/sku.7302

Current limit
http://www.dealextreme.com/details.dx/sku.1885

Laser diode from Lite-On LH-20A1P

I have custom programmed the converter to get settable brigtnes and "effects"  (uses PWM).
AMC7135 (2 peaces, one for laser, one for leds) soldered on board near inductor (in free space).

And there is one custom made ring, where the laser module is glued in with arctic adhesive, and then all screwed in the head.


----------



## IgorT

MatajumotorS said:


> I have custom programmed the converter to get settable brigtnes and "effects"  (uses PWM).
> AMC7135 (2 peaces, one for laser, one for leds) soldered on board near inductor (in free space).


 
That step up converter looks really interesting.. With this, one powerfull 2700mAh NiMh could power the entire laser, and allow it to be in a very small enclosure.

What is the output voltage of the converter? Is it filtered enough, or do you think an additional cap is needed?

Nice work BTW.

You really tempted me with that converter, cos i like building things small but still want a regulated LD supply, so one AA NiMh would be much better than the 6 needed otherwise.. And MUCH cheaper than a 2 cell LiPo. I think i'll be getting a few.


EDIT: Is it a two layered board or does it have three layers? I've seen some complaints on DX about it not coming pre-assembled or missing some parts.. Now i'm not so sure anymore..


----------



## MatajumotorS

the converter is 5v output, there are two one layer boards.
I will try 19-mode coverter when will receive it, it is more powerful and has settable output voltage.


----------



## IgorT

MatajumotorS said:


> the converter is 5v output, there are two one layer boards.
> I will try 19-mode coverter when will receive it, it is more powerful and has settable output voltage.


 
If it's 5V then a 317 current regulator wouldn't work with it..

But if the output is a stable 5V, even when the battery voltage is dropping, all i'd need on the output is a current limiting resistor and a cap or two.. It could even be used to power a blueray..

Do you have a link to that other converter?

Thanks!

Igor


----------



## IgorT

carmangary said:


> Hi all. I have read through here but I am still unsure of which one will do what I want. I need one to be able to do 200mw continuous. I will have it heatsinked of course. Has anyone run that hard continuously without it failing?


 
The Pioneer and the LiteOn should both be able to do that..

The one i'm currently using (from a Samsung TS-H552) also seems to be capable of this, but it is possible that i have a freak diode on my hands.. 


BTW: What do you need exactly 200mW of output power for?


----------



## MatajumotorS

IgorT said:


> If it's 5V then a 317 current regulator wouldn't work with it..
> 
> But if the output is a stable 5V, even when the battery voltage is dropping, all i'd need on the output is a current limiting resistor and a cap or two.. It could even be used to power a blueray..
> 
> Do you have a link to that other converter?
> 
> Thanks!
> 
> Igor


 
Here is the link: http://www.dealextreme.com/details.dx/sku.7882
with this you don't need no resistors or else. You can set the voltage to obtain needed current. Ofcourse it will warry because of temperature a little.
Other way is to use AMC7135 like me, you'll get 350ma limit, or you can add a resistor in paralel with ld to drop not needed current(if you need less than 350ma) like someone suggested before here.


----------



## IgorT

MatajumotorS said:


> Here is the link: http://www.dealextreme.com/details.dx/sku.7882
> with this you don't need no resistors or else. You can set the voltage to obtain needed current. Ofcourse it will warry because of temperature a little.


 
If it's possible to set it to 6V, i'd rather use a LM317 current regulator after it, to achieve constant current, even when it would start dropping otherwise due to temp..

But i understand what you mean.. If it's fine-tunable, you could just use it directly.. I would just add a 1 Ohm resistor for measuring the current, and a cap or to, for additional filtering and protection..

The variations from the temp. are probably neglectable.. I don't think anyone would even notice them..

Thanks for the link BTW.


----------



## newbie101

Hello,
Beginner here, and I am looking to get something EASY to start out with. I do not have much experience in the electronics department, but could one start with something like this: http://www.dealextreme.com/details.dx/sku.5914

and the unsolder the current diode and install one of these: http://sales.stonetek.org/ldc.html

to create a "beginner" burning laser?


----------



## MatajumotorS

newbie101 said:


> Hello,
> Beginner here, and I am looking to get something EASY to start out with. I do not have much experience in the electronics department, but could one start with something like this: http://www.dealextreme.com/details.dx/sku.5914
> 
> and the unsolder the current diode and install one of these: http://sales.stonetek.org/ldc.html
> 
> to create a "beginner" burning laser?


 
It is the same as Axiz module, i used it too, works great! And :welcome:!


----------



## newbie101

Thanks and I hope to learn from this site.


----------



## roSSco

LG 20X Dual layer w/ Lightscribe. 
Model# GSA-H55LI
open can
Driving it with 560mA  and it doesn't get hot! (in my well heat sinked flashlight mod).
It lit a match 20' away. oo:
I don't have power measurements...yet.


----------



## jake25

hey i'm a total noob ove rhere, i got a 16x laser diode from stonetek, the beam works but seems very broad not even close to a beam. is there anything i can do for this? i've heard about diodes being adjustable but i'm not sure if its possible.


----------



## roSSco

jake25 said:


> hey i'm a total noob ove rhere, i got a 16x laser diode from stonetek, the beam works but seems very broad not even close to a beam. is there anything i can do for this? i've heard about diodes being adjustable but i'm not sure if its possible.



It sounds like you need an Aixis module. This will allow you to focus the output.

Those are very good diodes btw. 


http://www.dealextreme.com/details.dx/sku.5914


----------



## jake25

i have an axiz module, i just place it in there and it will become a tighter beam?! i'm so stupid haha


----------



## roSSco

jake25 said:


> i have an axiz module, i just place it in there and it will become a tighter beam?! i'm so stupid haha



Disassemble it and *carefully* press the diode into it. Reassemble and adjust the lens.


----------



## jake25

roSSco said:


> Disassemble it and *carefully* press the diode into it. Reassemble and adjust the lens.


i already took out the old diode from the axiz model, press the new diode into the axiz module?


----------



## Phenol

roSSco said:


> LG 20X Dual layer w/ Lightscribe.
> Model# GSA-H55LI
> open can
> Driving it with 560mA  and it doesn't get hot! (in my well heat sinked flashlight mod).
> It lit a match 20' away. oo:
> I don't have power measurements...yet.


 




That's good news. I got 2 from a similar LGs - H55N /normal?/ and I take it they are identical to the Lightscribe ver.
Have you tried smth with the IR one? It is also an ~'open can' /missing window, the can itself is still there/.


----------



## roSSco

jake25 said:


> i already took out the old diode from the axiz model, press the new diode into the axiz module?


I usually use a drift punch and a light hammer.


----------



## jake25

i tried fitting the new diode in before, ( i dont have access to the supplies atm) and it fit in fine, do i need to do anything to make sure it stays?


----------



## roSSco

It should be obvious to the most casual observer that it will not fall out...if it is properly inserted.


----------



## fxstsb

I read thru several pages of post and did not see what I wanted . forgive me if this is coverd as this is my first post. Has anyone sucessfully replaced a weak laser in their DVD burner?


----------



## Joe Nobody

Where I live, the only place that sells DVD burners within reasonable travelling distance is RadioShack. The only DVD burner they sell there is the MADDOG MD-18xTFI. I have torn it apart before and the diode is open but it is a small, black, plastic rectangular diode. I don't know the output power and if anyone does know for any reason, could you please post your findings?


----------



## Phenol

Joe Nobody said:


> Where I live, the only place that sells DVD burners within reasonable travelling distance is RadioShack. The only DVD burner they sell there is the MADDOG MD-18xTFI. I have torn it apart before and the diode is open but it is a small, black, plastic rectangular diode. I don't know the output power and if anyone does know for any reason, could you please post your findings?


 it seems you have gotten a frame-type LD. in fact, if it is the only LD in the pick-up, i would assume that it is dual - combining the red and IR emitters in one package. if it has 3 leads, the middle one is probably ground /common for cathodes of both LDs/. The other two go to their anodes, respectively.
The output power is probably in the 300-350mw pulsed and 120-130mw cw range. for example:
http://www.rohm.com/products/shortform/20laser/laser_index.html


----------



## nabiul

I took apart what seems to be an old no name dvd-rom and found two closed can diodes and the optical pickup, is it normal two have two lasers or is one of them serving some other function?


----------



## Phenol

nabiul said:


> I took apart what seems to be an old no name dvd-rom and found two closed can diodes and the optical pickup, is it normal two have two lasers or is one of them serving some other function?


 
dvd rom you say.... in this case one of the lasers is red /dvd section/ and the other is IR /cd section/. the ir one is mostly useless due to its low power and visibility. the red LD is probably around 5-7mW @ 660nm, not much brighter than a cheap 3mw pointer


----------



## nabiul

You were right, one of them is a red, just a little bit more powerful than a laser pointer I think, but it heats up quickly at 2 volts. I think I fried the IR one however by reversing the polarity, my digital camera doesnt pickup any traces from it. 

Also what do you know about mini disc player lasers? I have one that seems to have both the laser and receiver in one packaged unit, theres also some kind of filter in front of it.


----------



## Phenol

nabiul said:


> Also what do you know about mini disc player lasers? I have one that seems to have both the laser and receiver in one packaged unit, theres also some kind of filter in front of it.


Mini CD players also have infrared LD as a light source. Its power may be even lower /~3mw.../ to further reduce power consumption from batteries. For me it is hardly worth extracting it. If you want burning capability, go for burner drives.


----------



## Kenom

wow talk about thread jacking!!! this thread has totally degraded from it's original intent of showing folks good dvd's to extract diodes from.


----------



## Kiessling

You're right. Please gentlemen ... let's steer this one back on topic and use other threads or start new ones for different topics. Thanx.
bernhard


----------



## Gazoo

Just a bit of an update. I ordered a couple of the Sony 20X DVD burners when they were on sale for $24.00 each including shipping.

http://www.newegg.com/Product/Product.aspx?Item=N82E16827118003

My first harvest of the Sony drive did not go so well. While I was removing the mylar some solder went down between the base of the positive pin where the pin insulator is and the case. This is the second time this had happened to me..I think I had too much solder on the tip of my iron. However the removal of the diode is the very easiest I have ever come across. If anyone gets this drive, simply remove the glue from the base of the diode. You will see a place on one edge of the base of the diode where you can pry it up. Just be careful not to let whatever you are prying with slip inwards as this could destroy the diode. I found once I got the diode lifted up on one side I was able to remove it with my fingers. That's how easy it is. There is no need to take the assembly apart and no need to do any cutting on the heatsink...very sweet. 

Since I felt a little ambitious, I decided to harvest the diode from Sony drive number two. This was even easier since I felt I was in familiar territory. This time I removed the assembly from the drive and held it in a vice. The first item of business was removing the mylar from the back of the diode. Then I proceeded to remove the diode and once again it almost popped right out...lol. I immediately mounted it into the meredith adapter, then soldered a capacitor to it. From there it went into my meredith module with an acrylic lens, and then into my TEC. 

The preliminary tests reveal it is exactly the same as he Pioneer 112D and 115D diodes. The voltage across it is the same at 2.83 volts with 350ma's of current. And the die is the longer one. So at least the diode should be as good as the ones we have been harvesting from the Pioneer drives. However the ease of harvesting this diode from the Sony makes the Sony the winner.

Being determined to beat VaThinks measurement of 400mw's, I moved the diode to my meredith module with glass lens. The glass lens outputs at least 50mw's more than an acrylic lens. Then I powered the diode with 570ma's and got a stable reading on my LPM-1 of 408.8mw's. Note I was using the ND filter on my LPM-1 and VaThink wasn't.


----------



## Kenom

Sweet news Gazoo. Now we just need to get senkat to get on finding these before they have been installed into a dvd-rw for $17 and were in shape!


----------



## Phenol

:thumbsup: Gazoo, would you be willing to run a short 2-week life test on one of these producing 350mW or so continuously?
it would be interesting...


----------



## Gazoo

Phenol said:


> :thumbsup: Gazoo, would you be willing to run a short 2-week life test on one of these producing 350mW or so continuously?
> it would be interesting...



Not with my Sony diode...it is "hot"..lol. And it is going in my next MXDL build. :thumbsup:

I think 350mw's is really pushing it. But 300mw's might be doable. This would take appx. 400ma's running to the diode and it would require a TEC. As you can imagine these get pretty hot running with high currents.

I might do it later on but not for 2 weeks..lol. If one of these can run for 24 hours straight putting out 300mw's, I think that would be pretty awesome.

Kenom I agree, if SenKat could find these and sell them at even $30.00 it would be one heck of a good deal.


----------



## lm921

a little off topic here and i should have done a search first but......
Would you think a hard drive would produce a better laser than a DVD burner ??
I removed what looks like a closed can laser from a hard drive but i have not tested it yet (I am new to lasers). 
i assume i need some glasses before i build and fire up any such device


----------



## pyrokid3

lm921 said:


> a little off topic here and i should have done a search first but......
> Would you think a hard drive would produce a better laser than a DVD burner ??
> I removed what looks like a closed can laser from a hard drive but i have not tested it yet (I am new to lasers).
> i assume i need some glasses before i build and fire up any such device




As far as I know hard drives use magnets not lasers. I do not believe that there are any lasers in hard drives.


----------



## CHP

Gazoo said:


> Just a bit of an update. I ordered a couple of the Sony 20X DVD burners when they were on sale for $24.00 each including shipping.
> 
> http://www.newegg.com/Product/Product.aspx?Item=N82E16827118003
> 
> My first harvest of the Sony drive did not go so well. While I was removing the mylar some solder went down between the base of the positive pin where the pin insulator is and the case. This is the second time this had happened to me..I think I had too much solder on the tip of my iron. However the removal of the diode is the very easiest I have ever come across. If anyone gets this drive, simply remove the glue from the base of the diode. You will see a place on one edge of the base of the diode where you can pry it up. Just be careful not to let whatever you are prying with slip inwards as this could destroy the diode. I found once I got the diode lifted up on one side I was able to remove it with my fingers. That's how easy it is. There is no need to take the assembly apart and no need to do any cutting on the heatsink...very sweet.
> 
> Since I felt a little ambitious, I decided to harvest the diode from Sony drive number two. This was even easier since I felt I was in familiar territory. This time I removed the assembly from the drive and held it in a vice. The first item of business was removing the mylar from the back of the diode. Then I proceeded to remove the diode and once again it almost popped right out...lol. I immediately mounted it into the meredith adapter, then soldered a capacitor to it. From there it went into my meredith module with an acrylic lens, and then into my TEC.
> 
> The preliminary tests reveal it is exactly the same as he Pioneer 112D and 115D diodes. The voltage across it is the same at 2.83 volts with 350ma's of current. And the die is the longer one. So at least the diode should be as good as the ones we have been harvesting from the Pioneer drives. However the ease of harvesting this diode from the Sony makes the Sony the winner.
> 
> Being determined to beat VaThinks measurement of 400mw's, I moved the diode to my meredith module with glass lens. The glass lens outputs at least 50mw's more than an acrylic lens. Then I powered the diode with 570ma's and got a stable reading on my LPM-1 of 408.8mw's. Note I was using the ND filter on my LPM-1 and VaThink wasn't.



Gazoo,

What were the markings on the 112D and the sony diodes?


----------



## MatajumotorS

pyrokid3 said:


> As far as I know hard drives use magnets not lasers. I do not believe that there are any lasers in hard drives.


It uses wery small coils for reading and writing.


----------



## IgorT

roSSco said:


> It should be obvious to the most casual observer that it will not fall out...if it is properly inserted.


 
That's what i thought as well.. Most of my LDs had some solder on them, because they were soldered into the heatsink, so when i pressed them into the module, they would never come out again..

Others also stayed in, even when they were completelly clean, but i just found one, that wobbles slightly in the AixiZ module.. So i just soldered it in, otherwise it would actually fall out by itself..


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## Joe Nobody

I recently bought a 20x DVD burner for $85. It is a LiteOn 20X Super AllWrite DVD Drive. It is very easy to take apart, which was a bonus to me, but the real treat were the diodes.

Open-can Form.
Visible at 650nm.

The output power in unknown... for now. It will definitely do everything one mentions a DVD laser will do, and much faster. VaThInK got a peak of 400mW from an 18X, so a 20X should be much better. When I make another one I will take photos of the process of turning a 3-LED $10 flashlight into an expectantly >400mW laser pointer. Aluminum machining necessary for the flashlight.


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## cdesigns

I opened my second DVD burner it was a HP DVD Burner with lightscribe feature (It burns a image or text into the top of the DVD with a special HP DVD's) 

Well the first DVD burner I opened was a very cheap LG unit, the diode was very powerfull see video and see

http://media.putfile.com/Laser-cutting-116-foam-fast

The HP DVD diode was not as powerfull, I had a hard time making burn a black tape, and it burned at 3.3v @ 350mAh.


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## IgorT

Joe Nobody said:


> VaThInK got a peak of 400mW from an 18X, so a 20X should be much better.


 
Actually, it would seem the open cans are the same in 18X and 20x writers.. All the electrical characteristics match, and so does the measured output power.


But i do think LiteONs have a short chip open can. Nobody knows for sure, if there is a difference, but the general oppinion is, that long chip is better, due to a larger contact area with the pedestal, for heat flow.




> When I make another one I will take photos of the process of turning a 3-LED $10 flashlight into an expectantly >400mW laser pointer.


 
400mW would be very hard to achieve in a flashlight... Those experiments were done with a LOT of heatsinking and even with Peltiers.


I am working on a similiar project. It won't be a flashlight, but a custom made enclosure, with a small 15x15 or 20x20mm peltier, with the hot side mounted on a heatsink with a tiny fan, powered by a pager motor, to make it all small and run off a low voltage.

I'm gonna use the long chip open can out of a Sony NEC AD-7191A..

But i don't think i'll get anywhere close to 400mW.. Except maybe with very short duty cycles. With passive cooling, they would have to be even shorter...

You can get 300mW out if it reliably and safelly tho, probably with a long lifetime.


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## j_enzo

Someone could send me a drawing of how to use this as a diode laser point, I have taken two of these two LG DVD recorders. Because I could not focus the beam.

Thankyou

Julio Enzo


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## j_enzo

petah said:


> HEY U GUYS!!!!!!!!
> any idea for collimating???????
> I have my dvd laser diode (open package) mounted in a flashlight, created a cooling system, 3,4V at 350ma power input as vathink recommended...... but I'm having some problems in collimating the beam, I don't have access to aixis case or stuffs like that from where I live, so any suggestion?
> I'd appreciate!!!



Petah, você conseguiu uma solução para colimar o laser? Eu tenho dois diodos que tirei de dois gravadores de DVD LG, eles são abertos, eu não consegui um facho paralelo, no máximo eu consegui um ponto com uma linha cortando. Eu compreendo mais ou menos o inglês, porém não escrevo nada, só com ajuda do google, então estou recorrendo a você já que vi em outro post que você mora na Brasil.

Grato

Julio


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## Kiessling

Julio, welcome to CPF !
This is an English-based forum though, and English shall be the language used. If you have problems please use a translator.
Thanx.
bernhard


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## petah

j_enzo said:


> Petah, você conseguiu uma solução para colimar o laser? Eu tenho dois diodos que tirei de dois gravadores de DVD LG, eles são abertos, eu não consegui um facho paralelo, no máximo eu consegui um ponto com uma linha cortando. Eu compreendo mais ou menos o inglês, porém não escrevo nada, só com ajuda do google, então estou recorrendo a você já que vi em outro post que você mora na Brasil.
> 
> Grato
> 
> Julio


 
Olá Julio,
bom, eu comprei uma lente colimadora do site www.dealextreme.com, custou apenas 4 dolares e alguma coisa.. já com frete incluso, mas não funciona perfeitamente tbm não, é possível focar o laser em um ponto em até uns 8 metros ( nessa distância consegui furar um balão), tbm dá de fazer um raio uniforme mas ele fica muito espesso, incapas de estourar balões ou acender fósforos, de qualquer forma se vc quizer... mas tenha sempre muito cuidado com esse brinquedinho, estava montando o meu e o disparei acidentalmente no meu olho, estou vendo uma mancha embaçada agora... cuidado!!!
se vc preferir vc pode ir até uma loja que venda equipamentos de vigilância e comprar uma lente para micro cameras, funcionam melhor que a que comprei, tenho uma dessas tbm, uma dica, peça a de "6mm" parece funcionar melhor, então arrume uma lanterne e seja criativo... outra dica, cuidado manuseando seu diodo, eles são muito sensíveis, queimam muito facil, sempre que tiver que pegá-lo tenha os pés no chão, isso mesmo, para não ocorrer uma descarga estática e queimá-lo.
boa sorte!!


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## DVD-LAZR

I got two DVD burners that didn´t work: first is Samsung SH-S223 and the other is an Samsung SH-D163. Both had strange, Red&IR Laserdiodes which were not in a 5.6 mm housing. I could only get a power of around 10 mW outta them. they seemed like reader diodes not like burner dodes!:thinking:


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