DIY Homemade laser diode driver

[Daedal]

o thought they were rated for 250mw senkats GB diodes so they can burn i want to push it higher if u can please tell me how..... oh yea 20%off techlasers for the first 20 buyers

Techlasers = STEER CLEAR

As about the diodes, they are rated to 250mW for pulsed operation. We are running it CW, and for that it's rated at 80mW, but we're pushing it quite a bit above it's intended operation

--DDL

 

[toked323]

well is there a way i can push to at least 100mw on cw tell me how i need a sexy laser

 

[Daedal]

5 Ohms will give you 250mA... that should get you at least 150mW of power

--DDL

 

[toked323]

not o sound gay but......i love you 1 more question dude were did you get that sweet case for ur blu-ray laser?

 

[Daedal]

HAHAHA... ;D

I love you too...

So... that was a case for something I saw in Walgreens (a local pharmacy). It was a small box for hair pins. It's tiny and fits things nicely, and figured it would make for a nice BluRay setup considering the oddly shaped battery I chose

--DDL

 

[Daedal]

Found it here...

http://www.flashsales.com/images/scunci/r16226.jpg

--DDL

 

[Daedal]

Yes... I know it looks far fetched... :

No... I didn't go looking for it... ;D

It just popped out The GF helped a bit too

--DDL

 

[Hemlock_Mike]

DDL --

Where did you get a blu diode ?? I've been waiting a month with Wiiroom. Excuses etc etc -----

Mike

 

[Daedal]

That's typical man... It takes me 2 months every time with SamSam, and it took the same with Wiiroom too... :-/

Nothing I could do about it but wait and hope for the best. But I'll vouch for him and for the diode in there man. It's worth the wait... trust me!

--DDL

 

[Gazoo]

The reference voltage for the LM317 is a steady 1.25V. Adding voltage on the input line is not supposed to change that, if it does, then it's a faulty regulator

--DDL

Daedal...thank you. I have been running the circuit with a constant voltage source of 6 volts, I did not bother to go back and check if current would change with voltage input since I have built my TEC. Lo and behold, any change in input voltage did not change the current or voltage readings on either my diode or peltier with my diode set at 200ma's.

However when I set the current for the diode at 250ma's problems began. When I went from 6 volts to 7.5 volts I saw I was pumping 500ma's into the diode.... I have a silicon diode connected to the input of the regulator and it is causing the regulator to go into LDO mode just a bit. Also the peltier has a silicon diode connected to it's regulator. I am going to jumper both of these diodes. LDO will cause all kinds of problems as I have just learned. It did not happen when I adjusted the diode for 250ma's at 7.5 volts, and turned the voltage up to 9 volts and 12 volts.

I do not know what I was doing wrong when I had it on the breadboard, however I now suspect it was bad connections.

Anyway, this is good...it will make it so much easier to work with flashlights or whatever and not have to worry about the input voltage. Although it is a good thing to keep as close to the to 6 volt input as close as possible for efficiency.

 

[Skram0]

Well, here's some pics of my driver. Took a few hours. But hey, who said fun has to be quick.. I used a 10 Ohm resistor since that's the smallest Radio Shack had. I also used a 1K Ohm potentiometer since that's the smallest they had in this size. But it doesn't matter anyway, it just makes the adjustment kinda sloppy.

In the first pic I'm driving a 5000mcd red LED at the driver max of 125ma. Can't drive it for long as the regulator gets hot, and I'd probably smoke the LED (already nuked a blue one ). I'll have to add a chunk of aluminum to it to cool it better. I thought it would be snazzy to add a power switch to. You can see in the background my 6v RS battery brick. I think it was cheaper to get that instead of some batteries and a holder.

The regulator stays cool when around 50-60ma. Start going 80+ and some heat forms. Maybe eventually I'll swap out the 10 Ohm for something smaller to get high than 125ma, but I dread dealing with that bus wire again. :-?

 

[Skram0]

another

 

[Skram0]

another

 

[Gazoo]

That's a nice piece of work...nice and neat. If you get frustrated with the resistor and pot, and if size is not an issue, get the RS 3 watt 25 ohm rheostat. You can use it with no other resistor needed in the circuit. The main reason I got them is because it was convenient and easy. If I use Daedal's circuit is a flashlight, of course I am going to use a multi turn pot like the one you used, make the circuit as small as possible and use a LDO regulator.

 

[xgpu]

I'm new at all of this, I haven't taken electronics since high school so I'm extremely out of practice. If I throw a 47uf capacitor right before the LD will that be good enough to extend it's life? how critical is it to limit current/amperage? I mean, if I have excellent cooling, will the current not be so lethal?

 

[-Witch-Doct0r-]

I dont think so bcuz the cap basicly just stores the power well i think so anyway but take no notice of me i am just a noob ask Gazoo he is online now! he should know PM him if u want a quik answer...