School Project/DIY Red Laser

[spyrorocks]

use a multimeter to measure the current that your driver is giving out, use a LaserCheck to measure the output of the laser diode in mw.

 

[wooooooolazer]

I think your confusing mw with ma, ma is the current the driver gives out, mw is basicly how strong the laser is.




....lazer.... ;D ;D ;D

 

[the_stark]

I'd aim for no more than 240ma's of current (ma), which will give quite a strong beam. Many people (including me) run theirs around that, and it's powerful yet not too overdriven for these diode.

To measure current, hook a 1 ohm 1/2 watt resistor up in Series to the LD, and measure current in Series to the resistor/LD. Measuring current in parallel will most likely kill your diode instantly. (you don't need the resistor to measure current, but i hear it is a good idea to have one.)

And make sure to short out the capacitor by touching the two leads together, and also make sure the circuit is off before connecting the LD. I made the bad mistake of not shorting it, and I lost a poor little diode... Lucky I bought 3

 

[rog8811]

Can I just clarify this a bit,

To measure current, hook a 1 ohm 1/2 watt resistor up in Series to the LD, and measure current in Series to the resistor/LD

When you hook up the DVM to each end of the 1ohm series resistor you need to have it set on volts not amps.

the meter will display mv and the number given is = to ma through the LD.

Regards rog8811

 

[Vcent]

Ahh...Thanks guys

 

[Phazonx]

Radio shack has those LM317's. I get mine from there.

 

[Gazoo]

Regarding the 1 ohm resistor it is best to use a resistor with a 1 watt rating. The voltage across the diode will be appx. 2.85 volts running at 250ma's. So 2.85 X .250 = .7125 watts.

 

[Vcent]

Radio shack has those LM317's.  I get mine from there.

Radioshack is NOT an option,since we do not have radioshack in Denmark... :-[
And internet Radioshack is not an option since the shipping cost involved would be crazy...

 

[Vcent]

would this go for a housing for a senkat diode? dealextreme.com/details.dx/sku.5914
and this as a switch?
dealextreme.com/details.dx/sku.5604

 

[the_stark]

Yep, both of those should work