Step 2: The driver

To make a proper driver for the laser diode, etch the PCB and solder the components as shown in the diagram.

Some people only connects the LD with a resistor in series, but that driver is a better (but more expensive) way to use a laser diode.

The LM371 varies the voltage the LD uses (i cutted the top because it didnt overheat, i think i does not affect the way it works), the two 10ohm resistors in parallel set the maximum voltage and current the Laser Diode will get, the pot allows adjustment of output current, The 1N4001 diode protects the LD from a negative input as battery placed wrong, but LM317 can't deliver neative voltages, so maybe it is not necessary, and the capacitor protects laser diode  from immediate  power supply especially when switching on.

This driver is a mixture of what i have seen arround, so, if something should not go there, please tell me.
Nitroxium1 year ago
Yo,I have a lens used in laser and a really powerful bulb.Will you folks help me in making a laser outta it?

It would not work because a laser diode does not produce light light a bulb, it concentrates light into a beam which is why they are dangerous and powerful. On the other hand, a bulb will produce light waves in a scatter and not a beam.

Do I need a potentiometer if I am going to keep it on max current? I want to make this I just don't want to spend an extra $3 for 20 100Ω trimpots (yes i know my schematic will be different) and have an extra 19. Can i substitute it with a jumper wire or make the connection solid?

thismatters2 months ago

According to my understanding of the LM317, the other end of the potentiometer should be connected to ground.

edvin19942 years ago
what size pcb need to be
pinomelean (author)  edvin19942 years ago
About an inch wide an as long as it still fitting into the battery.
If you're using anothes casing, it can be bigger.
waldosan2 years ago
the lm317 usually comes with a reverse voltage detector and safety crowbar/fuse circuit. voltage regulators in the lmxxx family are very sturdy, you literally cannot set them on fire without a torch since they have temperature safety circuits as well.