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FrozenGate by Avery

DIY Homemade laser diode driver

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chido said:
First, don't worry about voltage, think current ;) And second, how are you measuring the voltage?
Click to expand...

Im using a dmm in parallel to measure voltage. My input voltage is 6V. I would measure the current with the dmm but I can't get the setting to work for some reason.
 





I recommend you use at least 7.2v input, see the LM317 regulator keeps 3v to itself, and the laser diode takes about 2.5-3.0v, it depends on what current you're driving it at. If your input voltage is only 6v you're left with only 0-.5v, as soon as the batteries get drained, the current going to the laser diode will be less and less, making your laser weaker and weaker. Like I said use 6 nimh batteries or any other source that gives you 7.2v. If you can't get any nimh, then put in 5 alkalines, that will give you a total of 7.5v, although no body uses alkalines since they sag a lot.
Also, you don't need to use the current setting on your multimeter to measure for current.
Here's the thread on how to test your circuit:
http://www.laserpointerforums.com/forums/YaBB.pl?num=1197651171
 
I see what your saying, and thank you for your help but I am using the host flashlight DDL used in his "make your own laser thread" so I only have room for 6v. How did he make his circuit in his mod with only a 6v source? I now see how to test the circuit for current thanks to that handy thread. Thanks again for your help.
 
Chido, the rechargeables work great. Thanks for all your help and suggestions :)
 
How easy is it to modify this circuit to run off a +12v DC power supply (ie either a PC Power Supply's +12v rail, or else a 12v DC transformer to run off mains)? I've got a couple of dud DVD burners lying around, and am wanting a LD that can be used to heat stuff up. And since I'd just be using it around the home, running it off either a 12v transformer or the +12v rail on a PSU would be the easiest option for me.

Eller
 
this is an amazing thread

i received a recommendation to lock it though b/c there is already enough information here, and that some questions are getting repeated and would be better off as questions in new threads.

i honestly don't want to lock this thread since it is so epic, but if any of you guys think it should be locked please post with your opinion. i will only lock the thread if enough of you guys think it should be locked (4 or 5 people)

i think a better solution would just be to remind people to start a new thread for certain questions that are off-topic.

please let me know what you think


regards
-avery
 
SuperNova nice picture, I especially like the POT. What pot is that and where did you find one that small? Thanks
 
Hey guys,

I'm sorry if this question has been covered in previous pages but I really need to know, why hasn't there been a suggestion to screw an alluminium block heatsink to the LM317T? Or does it not get very hot at all?

Cool I'm gonna build another driver soon as I now know where I can get LM317T locally :)

Thx guys.
 
Sorry guys I've got another question.

I went away from the forum for a long time and back in the days the DDL driver used to make use of 2 x LM317T components. When and why has the design been reduce to only use 1 LM317?

Thanks in advanced.
 
cyclonite said:
Sorry guys I've got another question.

I went away from the forum for a long time and back in the days the DDL driver used to make use of 2 x LM317T components. When and why has the design been reduce to only use 1 LM317?

Thanks in advanced.
Click to expand...

It always has been 1 except for the ones DDL made and sold. One being used to regulate voltage and the other current.

Only 1 is needed to regulate current and that is all we are interested in doing.
 
Hi, i'm new in here sooo...
Well i wos wondering how much mA is safe passing trough a laser dode salvaged from a LG DVD recorder? I think it wos 16X... the first i had worked at 300mA no prob, but it burned out due to badly stabilized voltage. The second one fizled out in only 100mA... direct from bateries trough 2ohm resistor.... no cap aded, kinda didn't thought about it... using digital multimeter to check current.
Also when i conected the diode to check if it wos ok to the multimeter it mesured 1 ohm resistance.... and that when it still worked... can you give me some advice?
 
Cableguy said:
Hi, i'm new in here sooo...
Well i wos wondering how much mA is safe passing trough a laser dode salvaged from a LG DVD recorder? I think it wos 16X... the first i had worked at 300mA no prob, but it burned out due to badly stabilized voltage. The second one fizled out in only 100mA... direct from bateries trough 2ohm resistor.... no cap aded, kinda didn't thought about it... using digital multimeter to check current.
Also when i conected the diode to check if it wos ok to the multimeter it mesured 1 ohm resistance.... and that when it still worked... can you give me some advice?
Click to expand...

A harvested diode from a 16X burner should be able to handle up to 250ma's and last quite awhile IF you are using a driver and a capacitor in parallel with the diode.
 
On that circuit picture (the PC board one) that Supernova posted, where do the pos+ Neg- wires form the battery and to the LD go to? Maybe it's just me but I can't tell. Oh, and aren't 10 ohm 1/2 watt resistors a different color band sequence?
Thanks :)
 
The picture is self explanatory and correct including the color bands of the resistors. Brown, Black and Black bands indicates 10.0 ohms.
 
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