I need help on building/choosing a driver?

[ossumguywill]

So, I'm working on my very first laser. I'm using like a $10 diode from ebay, and the circuit I'm using uses an lm317, 1 capacitor, 1 diode, 2 resistors and a trimpot. So when I put the diode in my aixis module ($10, so i've spent about $30 so far) i can't get it to fit correctly, and when I do it's a little off direction, so not all of the beam is being used. But I get it in enough, so I plug it in and turn the driver up. Even when I focus it, I can't get it to burn anything, and then the diode just gets really dim. I think I killed it. So where is a cheap driver (i'm tired of throwing away cash) or do you have any tips to help me out? Thanks, Will.

 

[nikokapo]

The current may be too high, try turning it down a bit.

 

[ossumguywill]

The current may be too high, try turning it down a bit.

I don't really know how the driver works, it was the one kipkay showed in his instructable, but the voltage that i measure from it goes from like 1.8 to 2.9, and I dont know about the current.

 

[Mato92]

The voltage should be around 3V. To measure a current, make a dummy diode and measure the voltage in mV. You can make a dummy diode by connecting 4 1N4007 diodes and a 1 Ohm resistor in a series. Measure a voltage across the resistor. 1mV = 1mA.

 

[Meatball]

If this is your first laser, you might consider buying a high power module from Mohrenburg, just so you can see for yourself, what a correct setup looks like.
http://laserpointerforums.com/f64/fs-complete-modules-44555.html

$30 for a high power red, or violet with a driver attached!

 

[ossumguywill]

can anyone tell me how an lm317 decides what voltage to put out? I understand the current thing, but why does mine always put out between 2.5 and 3.3 volts no matter what voltage I give it?