Transistor as switch for battery powered laser pointer

Hi all,

While going through my box of bits I cam across a little red laser pointer which had a broken momentary switch so i thought i’d try and control it with the arduino.

Figured I could use a transistor as a switch and think i’ve got the circuit right but was hoping someone would check if you’ve got time.

Looks OK to me.


Great ta Lefty

Why not connect laser directly to arduino output? cut off battery right where this switch, solder wires and drive laser via 100 Ohm resistor with PWM

Hi Magician,

Yep thought about that as well, but wanted to power the unit independently, however I have ordered a module which I will connect directly.

Thanks for the thought.

It seems a good solution.

I would suggest you have some reading for "using transistor as switches" Googling would give u a lot of good resources...

check this for instance