Selfmade 3-mode 2W blue Laser"pointer" in customized solarforce body

[qumefox]

If you swap your 3 way toggle for a 1k pot, and do minimal rewiring between the LM317 and the NPN, You can go from having 3 modes, to infinitely variable brightness and only end up having to add one additional resistor to the circuit.

At least playing with it in the simulator I can get it to vary from 40mA (which should be just below lasing threshold) to 1.8A relatively linearly.

 

[Xuaodian]

That looks cool, looks front heavy with all that heatsink

just a idea, instead of using the tiny heatsink on the NPN is there anyway for you to attach it to the main cooler using a non-conductive thermal pad?

 

[qumefox]

Since people have been PMing me about schematics for the infinitely variable version, here you go.. Though I must stress.. anybody using this MUST set the output of the LM317 using the trimmer to suit their needs and the exact components. In the simulator this varies the output to the load (laser diode) from 100mA to 2A with the trimmer set to 240 ohms, however I can't be certain of the accuracy of the LM317 model I have for LTspice, nor the TIP-41 model I found.

So people should build it on a breadboard and test it on test loads before sacrificing any LD's to this. I also recommend using a high quality potentiometer between the LM317 and transistor as well, since this is the one that will control the dimming.