Because of some missed communications this Easter, I had a little more time on my hands than I expected. So I decided to resurrect an old project that I have neglected for a while. The result is pictured below. On the left is an Arduino Duemilanove powered by USB and on the right are 4 laser modules of the same power output you might find in a laser pointer. Since the lasers each draw more current than an output from the Arduino can provide, the chip in the middle of the protoboard (a ULN2003A) provides the necessary current on a signal from the Arduino. The device at the bottom of the protoboard is a 5V regulator so the whole thing can be driven from a battery or a wall-wart without the need for a USB connection.
The ultimate goal is to create a light-show by having the lasers attached to the ends of your fingers. I'm going to be playing around with the software to provide cool effects while I think about how to make the whole mess robust enough to survive on a dance floor.