DIY Laser Lightshow for $80: Useless but Awesome

What's cooler than a green laser? A green laser that paints semirandom moving spirograph patterns on your wall. Toronto-based hardware hacker Artur Petrovskyy shows you how to make one of your own from about $80 in parts in a new how-to on Instructables.com: Laser show for poor man.

Apart from the laser, the key to the magic is three mirrors mounted on motors, positioned so that the laser beam bounces off each mirror in turn before it passes out of the box and onto your wall. Petrovskyy mounted the mirrors slightly off from perpendicular to the motors' axles, so the mirrors oscillate as they spin. The combined motion of the three motors gives the laser beam a lovely eccentric path, which you can control by twiddling three knobs that vary the speed of each motor. Petrovskyy also added a microcontroller to randomly change the motors' rate of rotation.

Not only does this project look fun, but it's also relatively inexpensive and seems fairly achievable, even for someone with minimal gear hacking skills such as myself. OK, so chip programming is probably beyond me -- but I believe you could do a simpler, analog version by connecting the potentiometers under the knobs directly to each mirror's motor.

Petrovskyy points interested people to a $17 green laser module from DealExtreme.com, and other parts are probably available from Edmund Scientific, Jameco, or your local Radio Shack.