# DVD burner laser diode... Burning (video)



## dr_lava (Jan 22, 2007)

A little while ago many of us had a group buy of cheap dvd burner laser diodes. While the diodes are in, we're still waiting on the shipment of lenses. In the mean time I did a little demo that I thought would be fun to post here given recent DVD burning thread. Not many red lasers can do this!

Heavily compressed for dialup users.

Vid1

Vid2


Enjoy!


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## Hemlock Mike (Jan 22, 2007)

Looks like 200 mA does the trick !! I'm waiting  


Mike


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## SenKat (Jan 22, 2007)

http://stonetek.org/VIDS/dvd-laser.wmv My homemade DVD-burner laser BEASTIE !


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## dr_lava (Jan 22, 2007)

Nice, what current are you running at?


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## Hemlock Mike (Jan 23, 2007)

Senkat --

Nice video !! I machined a dvd diode holder from a greenie holder tonight. Removed all but one lens but it isnt the right focal length to get all the beam. I was up to 320 mA and could barely feel it but it was bright and focused. !!

Mike


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## liveforphysics (Jan 23, 2007)

Cool vids! Looks like fun!


I just toasted mine 10mins ago  Since Roithner laser doesn't seem to get my emails asking to buy the EU38 drivers, I took the driver from one of my AtlasNova CPF specials. I adjusted the lens to make a nice tight little spot useing low current, then progressively turned it up brighter and brighter. It was VERY strong, and had a pretty decently visible beam in a dimly lit room, with an insanely bright spot. I am impressed and pleased. Then I continued to turn up the power until it dimmed, and now its weaker than a <5mW... Poor little diode  

Well, off to order more DVD burners!!! I dont really care for the diode case on the LDs in the liteon 18x burners, so if anyone knows of a model with a more friendly LD caseing I would appreciate knowing before I go and buy a bunch more.

Best Wishes!


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## liveforphysics (Jan 23, 2007)

Just bought 5 LDs from Dr.Lava, and I allready bought a couple more models of DVD burner before that, so now I should have pleanty of little LDs to torture 

I will keep you guys posted with the results


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## Hemlock Mike (Jan 25, 2007)

Dr_Lava --

I'm still drooling - almost dehydrated !! Any word on the lenses and shipment ???

Mike Connor


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## Madz (Jan 25, 2007)

How much for the diodes again?


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## SenKat (Jan 26, 2007)

dr_lava said:


> Nice, what current are you running at?


 
I'm running it at 650ma, with a current limiting diode, a 1Kohm resistor, and a power led for looks ....you can SEE when this bad boy is lit up, no real need for the LED - but, I friggin love LED's !


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## SenKat (Jan 26, 2007)

Hemlock Mike said:


> Senkat --
> 
> Nice video !! I machined a dvd diode holder from a greenie holder tonight. Removed all but one lens but it isnt the right focal length to get all the beam. I was up to 320 mA and could barely feel it but it was bright and focused. !!
> 
> Mike


 
Thanks, man - I used an Aixiz 10mw module for the housing for the diode...focusing optics, AWESOME fit ( a LITTLE tough getting it in there 100% correct - but with patience, it CAN be done !)


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## Hemlock Mike (Jan 26, 2007)

I damaged the power lead on my diode mechanically tonight mounting it in the new heat sink :-( --- Dr_Lava ----- Where are you with diodes ????

Mike Connor


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## dr_lava (Jan 26, 2007)

hey, there! I contacted a Chinese manufacturer offering the same lens/cases as in the group buy, so that I could go ahead and order from them now that it's taking so long to get them from the original supplier. Well, a few emails later they referred me to the original supplier, because she is in fact an employee of that company stationed over here in the states. Long story short, they said 'I guess you really want these' and re-shipped our lens/case order to the US for me before waiting for a larger order to build up. It should be In the U.S. in Texas next week, and I'll get them to 2nd-day it to me for distribution. Everyone who missed out on the lenses already has diodes from the GB, sorry! I guess that ol proverb applies 'last shall be first, first shall be last.' 
Beleive me, I'm as anxious as you to get this over with!


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## Hemlock Mike (Jan 26, 2007)

Dr_Lava --


I can see this is a nightmare !! That's why I don't want to try getting a hundred 808's from China.

My housing is all machined to fit into an old Leadlight and I busted the LD wire loose :-( Seems I always do everything right until the last moment ....

Thanks for your work here --

Mike Connor


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## Hemlock Mike (Jan 27, 2007)

Stupid Me !! I took another DVD apart and harvested the "little precious" diodes. I very carefully soldered leads on the "red" diode and soooo carefully mounted it in my case assembly. What a sick beam !! Turned it up and it died :-(

Idiot - I had the IR diode. Another 45 minutes work and I'm red again. Now to bring up the mA... How much ??.... Wish my wattmeter had arrived.

Mike


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## Hemlock Mike (Jan 27, 2007)

Senkat --


I watched your video again and you report 177 mW. Elswhere you report 650 mA to get it -- That's a gawdawful lot of current !! Is this a 5.6 mm can ?? What are you using for a current limiter? I assume your rechargeables are NiMH.

Mike


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## dr_lava (Jan 27, 2007)

Well, I finally blew out one of mine in testing, so you're not alone. I was cranking up the current to 300mA and noted that the Voltage across the diode had risen to 3.3V. I then hooked it directly in series with 2 AA's that were showing a 3.25V resting potential. A flash of light! and it was gone. Post mortem autopsy concluded that it died of excessive inrush current. I'm going to be including a capacitor along with the resistor for our gropup buy kits to prevent just this. The cap should be installed parallel to the diode after the resistor.

On a different note, with focusing I was able to melt/burn a pinhole 800um wide and several millimeters deep into the black handle of a plastic screwdriver from about 2 feet. Right now I'm wondering if I leave it on long enough, will it cut an entire inch all the way through? hmmmmm


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## Hemlock Mike (Jan 27, 2007)

Dr_Lava -

It looks like you were right on the edge. The new batteries may have dumped a surface charge to do that. When dealing with 0.01 +/- volts, you aren't fast enough to gather all the post mortem data !!!! I don't know if a RC time constant would have helped. I'm going to try using and old Leadlight APC on mine tonoght but the diode does not appear to have a feadback diode. I'll have to rely on balast resistor feedback. 

Thanks for the good words -

Mike


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## dr_lava (Jan 27, 2007)

it's not just about surface charge on the battery, it's dealing with the properties of the laser diode. It has different properties below and above lasing threshold, and if you spike it with enough voltage before it's lasing, it sucks in a lot more current than if it were in steady state. That diode I had driven all the way to 400mA steady state while it was lasing, so it wasn't on the edge at 300mA. The R/C circuit is intended to give the diode time to start lasing and increase its resistance before the full power is dumped into it. The alternative would be to simply increase the resistance and live with a lower steady state output power, but I don't want to do that to you guys.


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## Hemlock Mike (Jan 27, 2007)

It's funny how Ohm's law does not apply with semiconductor junctions. I've noticed the "knee" in the current curve as I adjust them up. 

Thanks for the help and support. We all appreciate it.

Mike


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## Hemlock Mike (Jan 27, 2007)

It appears that a red DVD diode has a higher junction voltage than an 808 at the same current. Anyone have similar measurements ??

Mike


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## dr_lava (Jan 28, 2007)

I concur, at least for the ROHM red diodes vs the leadlight 808nm pumps.


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## jkaiser3000 (Jan 28, 2007)

Just out of curiosity, in the diodes we're getting, is the case negative or positive?.

I read some time ago that IR diodes are usually case negative and visible diodes are usually case positive.

Seeing as I haven't tested any visible diodes yet, I can't say whether that's true.


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## Bimmerboy (Jan 28, 2007)

That was one of my 500 questions in an attempt to drive Dr. Lava nuts early on in the GB... lol.

These particular diodes happen to be case negative.


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## Hemlock Mike (Jan 28, 2007)

All the 5.6 mm cans, both red and IR, that I've harvested from DVD's are case negative. They can be built either way.

Mike


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## trivergata (Jan 28, 2007)

This is going to be fun to play with, for sure!

Josh


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## Hemlock Mike (Jan 28, 2007)

Mission accomplished -- sorta ---

I wanted to put a red DVD laser into an old greenie. I have done so but the two e2 batteries straight into the diode give me 250 mA at 3 volts. It looks good and will pop balloons but is kinda underpowered yet. I will probably build my next one into a flashlight using 3 cells when the new stuff arrives !!
But --- It still looks good !!!!!

Mike


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## dr_lava (Jan 31, 2007)

Here's one I call 'Old technology, meet new technology!'

 Vid3

(Divx encoded)


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