Red DIY DVD laser burner.

[a_pyro_is]

[quote author=Kenom link=1181635652/135#140 date=1190300260]Figured I would chime in here with the specs of the 4 I've made in the dorcy jr host so far.

138.1mw
154.2mw
167.3mw
176.9mw

I wonder why there is a big difference in the power output in these...I would have thought it would have been more consistent.[/quote]

We know each diode is a bit different. Maybe the differences in the Dorcy drivers are compounding it.

 

[a_pyro_is]

Ken:
Could you please tell me what you've been reading as a typical voltage drop across the GB LD on the dorcy? My VOM isn't that great but I think I read about 2.25 volts. Sound right? Thanks!

Not Ken, but my 2 GB diodes were both around 2.75 Vdrop at 220mA. But I prob. need to retest as I was just given a much nicer meter (Fluke 111) than the Radio Shack POS I was using.

 

[photongeek]

[quote author=photongeek link=1181635652/135#138 date=1190293804]Hey Guys:
This may be a newbie question. While reading the LD spec sheet for the first time, I noticed the typical CW specs were 2.5vdc @ 130ma. Now if you go down to the graph you can see that anything above that current, it's talking about pulses of 40 nano seconds not CW. Are we not drastically shortening the life (or killing) of these LD's by driving them above 300ma? Thanks.
Rob

These diodes are rated at thousands of hours of life when properly driven by pulsed operation etc. in their intended DVD burners. If we use a extremely conservative estimate 1000 hours (very, very low.) for their pulsed operation service life, and we assume an extremely liberal estimate that driving them at around 350mA reduces the life span by 95%, that's still 50 hours.

Normally when burning tape, lighting matches, or just plain showing off we'd only leave these diodes active for a minute at a time or less. That's still 3000 activations for the high powered portable you've built, and I've probably fudged my estimates by a factor of ten in some places in favor of being conservative.

If you don't insta-flash your dode on it's first activation, or leave it on for much over a minute at a time, it'll probably last you years.[/quote]
That's a very interesting way of looking at it AJ. AND, a lot of popped balloons!

 

[LarryQ]

[quote author=photongeek link=1181635652/135#143 date=1190313812]Ken:
Could you please tell me what you've been reading as a typical voltage drop across the GB LD on the dorcy? My VOM isn't that great but I think I read about 2.25 volts. Sound right? Thanks!

Not Ken, but my 2 GB diodes were both around 2.75 Vdrop at 220mA. But I prob. need to retest as I was just given a much nicer meter (Fluke 111) than the Radio Shack POS I was using. [/quote]

Quick Question...

How are you measuring the vdrop across the diode....

Pictures or a diagram...or simply "Put the black probe here..red probe here...." hehehehehe

I'm not feeling too smart today!

Larry

 

[a_pyro_is]

Just measuring the voltage between the two LD pins.

Black probe---->LD<----Red probe
/ \
To Driver Circuit

LOL

 

[LarryQ]

THat's what I thought you meant...I'm not as LOOPY today as I thought!!!

Larry

 

[photongeek]

Just measuring the voltage between the two LD pins.

Black probe---->LD<----Red probe
/ \
To Driver Circuit

LOL

Hey Pyro:
That is one of the coolest ways I've seen of describing a circuit!

 

[kdubbz]

I got my first two diodes from the group buy, but The next group buy needs like 150 diodes, and its at a little above 60 now... so it will take some time. Near the end of the GB Ill probably get some.

 

[trist-10]

Going back to the walkthrough, you say to remove all the solder from those other connections using a file. Is this necessary? I don't really see a point to it as I'm afraid I might wreck the circuit board in the process..

 

[Kenom]

removing the solder just prevents connection to the module on accident.
It is not necessary just a step I go to to make sure it's nice and clean.

 

[a_pyro_is]

LOL

Photongeek, I'm glad you liked it.

Kenom, I've always used the trick like Greg described. To tin the wire with just a tiny bit too much solder,

flux the pin I'm soldering to, touch the tiny ball of solder left on the wire to the pin, and heat. Normally with my 15W iron it takes much less than 1/2 second, and leaves the pins looking like they're welded together with almost no solder visible.

Please pardon the poor image quality as I don't have my camera with me.

 

[SenKat]

Of COURSE the way greg described works best...geesh, people ! LOL !!! KIDDING !!! ;D ;D

It may not ALWAYS be the best way to do it, but I have had phenominal results thus far with it like that...

Greg

 

[a_pyro_is]

LOL @ Greg!
And the diode stays completely cool. Happy LDs make happy me!

 

[trist-10]

A very sad day today for me I soldered my extended LED pins onto my diode, and was happy to see a powerful beam coming out of the lens. I then soldered it onto my dorcy, only to find the diode had been reduced to a dull LED My guess is I took too long soldering it onto the board and let too much heat get to the diode. Ahwel, I don't think I've got the motivation to make another one lol

 

[MrBurns]

trist: I feel you.

I'm pretty competent with electronics, and my soldering has improved greatly since college (I was dangerous!) but nonetheless I've killed two diodes so far.... The wasted money is stressin me out too! Hopefully I've improved my handling technique with each successive attempt and the third time will be a charm, but damn you start to wonder whether you should just save up and buy a commercial laser!

still, both the diodes I toasted were open cans (liteon 20x and  pioneer 112d 18x) and if I'm successful on my third attempt (probably another 112d), that's ~120 (including other supplies) for a 250mw-ish red.

anyone think switching to closed cans would make a big difference in my kill ratio? or does the power of the open cans outweigh the risk?

-mrb

p.s. If DX would just ship me my 30mw green this wouldn't bug me so much.. 5mw just don't cut it!

 

[trist-10]

Thanks Burns, I don't feel quite so bad now