How can I make a laser wall so when something passes through it, it will make a sound?

Question

i can put it on a soccor net & it will make a sound if something passes through it

Answer 1

Hi!

This is easy way.

First you need diode laser (red ones cost less) then you need one piece solar cell and two mirrors length is let say 1cm less than your wall height and width can be 1cm. You put that diode laser upper or lower corner slightly up or down (if unit is up then laser must be pointed slightly down) how much? Depend how small thing must trigger alarm and how long is your wall. if you want at very small object trig it then angle must be so small at beam goes up or down only one beam diameter when it hit another end your wall. If you want at biggest thin that can go through your wall is 10cm then beam can goes up / down that 10cm. then you put mirrors one just up or down that laser diode and another comes another side your wall. Mirrors must be assembled very carefully at beam can go all way up or down. Now you put opposite corner than laser diode that small solar cell. If everything is done well you can get that laser beam hit that solar cell. Now you can use that solar cell voltage to trigger any relay (if solar cell don't give enough volts for that relay you may run small amplifier whit it. When solar cell can operate that relay you can use relay to switch some sound device on and off.