Just started a dental flashlight project

[constantine_a_f]

Over the last days I communicated with several companies capable of making a heat pipe on demand. Two of them told me that it is impossible to make it that slim and light and one said that it could do it for 700usd but thought the heat pipe wouldn't work very well as a heat dissipater. Therefore I am back to my aluminum tube+heat sink design which was meticulously tested by forum member Harold B and worked fine. I ordered the parts mentioned above with only one difference. I got a 6500 K and a 4100 K rebel. I expect them in 6-10 days (probably 10 because of the orthodox easter vacation, here in Greece). I will know how to solder by then and I will also find the aluminum tube or rod (I have not yet decided whether to make it out of a rod or a pipe/tube).

Thank you all for supporting my project.

 

[kosPap]

why don;t you combine both?

make the light out of a cylindrical auminum section then take a CPU heatsink, drill a hole the size of the cilidrical section and the mill the heatsink round around this...in effect you will make a cooling sleeve..it will not be the same but press fitted and tehrmally epoxy bonder will offer considerable gain....

now in Greek....
kane ena kylidriko maniki apo mia psiktra epe3ergasti

 

[constantine_a_f]

I found this

http://www.allerc.com/hyperion-20-mm-heatsink-p-1887.html
Do you think it is possible to use the carclo lens without a holder, or cut the base of the holder and use only the base? Will this provide the needed heat dissipation? The diameter of the holder is 21.5 mm. I could mount the lens without the holder, use epoxy glue to fix it (or make a fastener, then glue the star on a 20mmX1cm high aluminum rod and insert it from the other side of the heatsink. This way the heat transfer would be

led->star base->aluminum base->heatsink body.

Can this work??

 

[srfreddy]

Colour Temp and CRI are separate measures.

6500 is sunlight and no-one complains that sunlight has a low CRI.

LEDs don't have the smooth spectral response of sunlight and generally the cooler LEDs have a worse spectrum, so people associate a high CT with poor CRI.

High-CRI LEDs generally have a mid-range CT

What I'm saying is that cool white leds don't have good CRI-and plus, CRI is based off a blackbody radiator under a certain color temperature.

 

[constantine_a_f]

I have a final design. I decided to make the heat sink and the body out of aluminum. I will use a solid rod for the heat sink (see draft) and a tube for the body. I will glue them with thermal epoxy. My gf is a civil engineering student and helped me calculate how much heat dissipation is needed. The final design made by aluminium 6060/1/3 will be more than enough for the 2.1 watt rebel (at 700mA).

http://www.2shared.com/document/gn2QToiR/Drawing2-Layout3.html

 

[ledpwr]

I have just noticed that luxeon has brought out a new rebel ES (LXW8-PW50), it has a colour temperature of 5000k, it has a cri of 85 and an efficiency 110 lumens/watt.
But since it has a larger die (same size as an xp-g) it will have produce slightly wider beam (1.4 times wider). You will have to wait a few weeks for shops to get it in stock though as it is new.

 

[constantine_a_f]

I have just noticed that luxeon has brought out a new rebel ES (LXW8-PW50), it has a colour temperature of 5000k, it has a cri of 85 and an efficiency 110 lumens/watt.
But since it has a larger die (same size as an xp-g) it will have produce slightly wider beam (1.4 times wider). You will have to wait a few weeks for shops to get it in stock though as it is new.

That's the good with this design. I will be able to upgrade it. I already ordered some leds. I will start with them and then upgrade from there. In order for the design to be upgradable, I will attach the lens and the holder mechanically and I will not glue them with epoxy.

Thanks Ledpwr

 

[srfreddy]

The LXW8-PW40 are what Zebralight is going to use for their High-CRI line of lights-warmer than the 5000k, but I think I would prefer the 50 over 40, but I have no experience with anything other than incans and cool LED's.

 

[MikeAusC]

. . . . I decided to make the heat sink and the body out of aluminum. I will use a solid rod for the heat sink (see draft) and a tube for the body. I will glue them with thermal epoxy.

Keep in mind that the best Thermal Epoxy has a Thermal Resistance 30 TIMES higher than aluminium, so make sure there is a large metal-to-metal contact.

Epoxy should only be used in the thinnest possible layer to fill in surface irregularities.

 

[kosPap]

I found this
Do you think it is possible to use the carclo lens without a holder, or cut the base of the holder and use only the base?

probably only the latter..usually the holders alingn the LEd to teh optic and take care of the proper focusing distance

also, did you see thsi?

http://www.cutter.com.au/proddetail.php?prod=cut955 - 9.9mm

http://www.cutter.com.au/proddetail.php?prod=cut962 - 16.1mm

since you will mounting them on the glasses?

 

[constantine_a_f]

probably only the latter..usually the holders alingn the LEd to teh optic and take care of the proper focusing distance

also, did you see thsi?

http://www.cutter.com.au/proddetail.php?prod=cut955 - 9.9mm

http://www.cutter.com.au/proddetail.php?prod=cut962 - 16.1mm

since you will mounting them on the glasses?

Thanks for the link. I already ordered some parts. I will start with them and then try other stuff. I think the angle of the lens I chose was right. I will buy some xpg probably during the summer. The total diameter of the flashlight is going to be 25mm and the weight under 40 gr. I will post some pictures when they arrive.

 

[constantine_a_f]

The cnc job is done, courtesy of Mr. Michael N. I post some pictures bellow:

http://www.2shared.com/photo/56ouBCIg/IMG086.html
http://www.2shared.com/photo/_iC0VJQ7/IMG087.html
http://www.2shared.com/photo/X0USAKyg/IMG084.html

 

[constantine_a_f]

I am waiting for the electronics to arrive. I also started practicing soldering and bought some 23 ga wire. I thinking of annodizing the body. The heat sink was pressed inside the tube, so no glue or paste was used. There are no obvious gaps. Also, what do you think about this

http://www.all-battery.com/li-ion18...rypackwithpcbprotectionandhitecconnector.aspx

Are they safe or should I stick to the original 8 AA pack plan?

 

[constantine_a_f]

Hello,

I hope somebody is still following. I might need advice soon.
This is the build

I will post pictures as soon as I am allowed. Until then, download them.
(*Thanks to WalterK you can actually view the pictures now)

Pic.1 20 AWG wire (only pink colour found, I coloured the edge with a pen in order to distinguish - from +), 0.10 Euro (5 meters)
Pic.2 Thermal shrinking tubes, two sizes, 0.20 Euro
Pic.3,4,5 The aluminum body. Made from 7075 aluminium alloy, weighs 18 gramms ?? Euro (I guess around 40)
Pic.6 Thermal paste. I will use it to hold the led star in place (not glue it, just hold it), 1 Euro
Pic.7 I bought a 8 battery holder and 8 rechargeable energizers batteries (2000 mAH) for 25 Euro
Pic. 8 Luxeon drive buckpuck 700mA with external pot, 20 Euro, the leads were already tinned (it helped a lot)
Pic.9 I mounted the led on a heatsink (from an old laptop) to test it. I realized the paste actually held it to place even if I turned it up side down and hit it with my hand (NICE!!)
Pic.10 The led worked fine, as expected
Pic.11 Now for the difficult part. I cut two pieces of 1.5 m wire, I passed it through the holes at the bottom of the body and I soldered the into place. Then I put some paste on the back of the star, I pulled the wires back, I pushed the star to remove excess paste, I used a q-tip to remove the excess. Finally, i threaded the wire through the heat shrinking tube and pushed the edge of the tube so that it would hold the star in place. I used a bunschen burner to shrink the tube.
Pic. 12 The led star in place
Pic. 13ab I check it before putting the lens in
Pic. 14 The carclo 8.9 degree optic with round 20mm holder, 1 Euro
Pic. 15 Fraen 9 degree optic with holder, 1 Euro
Pic. 16 I placed the Carclo optic in place, beam from 500mm (not the best shot, I know)
Pic. 17 Fraen optic
I used Pattafix (2 Euro) to secure the optic in the body. There was a tiny margin so I just used pattafix around the holder and then pushed the optic until it got into position. This secured the star as well. It was so good I could not get it out easily.
Pic. 18 I bought this external battery (13 Euro) (5v usb supply, 1800 mA, charge indicator). The white card is credit card size. I will use a luxeon minipuck (2009) to power the led via usb (I will strip the usb wire and solder it on a switch). I will check this option before finalizing any connection (I have not soldered any wires, except from the ones on the led).
Pic. 19 A quick connection for the wire.

There is more to come.
Please post your opinion.
Thanks

 

[ergotelis]

Constantine it is better use other batteries rather than energizers, these are only good for recycling!
Buy some eneloops and you are done

One question, where did you mounted the driver?behind the led on the body of the headlight? If so, it is ok!

Very nice project, are you happy with the result?

 

[constantine_a_f]

Hello ergotelis,

I used 20 awg wire to feed the led. The driver is 1.2 m away. I emailed luxeonstar about this and they said that under 2m it is ok. I am happy with the result. I powered the led for 24 hours at 30% (where I am going to use it) and the batteries still held strong. I will probably use the usb battery though (it weighs 100 gr). The led works better I think with the Fraen. Even at full power after an hour or so the flashlight is cold (not mildly warm, it is cold). I did not mount it on the glasses yet, but it weighs 28 gr. totally so it is really nothing. Some fellow students asked me to build them one. They will pay only the expenses ofcourse.

 

[ergotelis]

If you want to have less weight, a good way might be to use some quality 18650 batteries, though you will need another battery holder and charger!
1,2m for only ~3,2V and 0,7amp is quite high i think, hope you are sure you have made the connections just fine. I would rather add the driver into the body,though it might difficult in your present configuration! It is better to have ~9,6V and 0,3amp on the wires rather than what you have right now. You just waste less power!

30% for a rebel led working at 700ma might be about 30-40 OTF which is, as we said ,good enough for you job!

 

[constantine_a_f]

I thought of connecting the driver beneath the body, but it was to bulky. I understand I am wasting power but it is ok. I also received a 350 mA, 100 Lumens 90 CRI rebel today and I will connect it as well to see what happens. I just want to use the usb battery as a trial (the micropuck will work as a boost/buck drive, buck from 5V to 3V and boost from 3 to 1). I might end up using 8 AA eneloops (the new black ones). It is easy to try right now, so why not.

 

[Walterk]

Nice to such fast progress.

There is a way to post photo's though:

.
You can see the link when you ask for the properties of the image in the links you posted.

 

[danboy]

Hello constantine!:wave:
When i first saw the Heine headlight, i was amazed by the focused high intensity beam. I was looking alot for some information about loupe light DIY construction/mod but found very old posts, pretty much satisfied with neat optics, broad beamlight, until i saw your work. problem is i can't see any photos of what you got at the end of it, could you please repost the links or the photos?

Im now in a middle of constructing a headlight for my Heine loupes, but got stuck with the optics.. i dont know which lens i have to use for that matter.

thank you!