Where can I get a laser and a sensor? (preferably cheap)

I'm looking for a laser that is button activated and a sensor that reacts to the laser.

Basicly I want to put the laser in the barrel of a broken bb gun and make the button so that when you pull the trigger the laser goes off. Then I want to make a circle with the sensor in the center and when you hit it  with the laser you hear a sound.

Now I am wondering where I can get a laser and a sensor that responds to it. the laser can be visible or invisible I don't really care. Also does the sensor respond to any laserbeam or is this specific?

Thanks in advance,


lofty7 years ago
Go to the pound shop and get a cheapo laser pointer, rip the case off and solder wires to the batter contacts For the sensor you can use a photo-diode, I've used lasers and photo-diodes before for my electronics coursework, scalextic lap timer lol :) Put the photo-diode with a resistor in a voltage divider, make that trigger a monostable 555 timer and have that enable an astable 555 timer to make the noise
Sounds like a Best Answer to me.
Look at the 2nd circuit down HERE - You'd replace the switch with the photo-diode and may have to increase the top 47K resistor value. (You could use a 556 which is 2 x 555 in the same 'box'.)
Yup, that circuit shows pretty much what I was thinking, and a 556 is a good idea, I didn't think about that :)

If you don't have 555/556 timers you can make an astable with NAND gates / transistors /op amps and a whole heap of other things and you can create time delays with resistors and capacitors too.