I decided to try and build a really cheap POV display in one afternoon using only parts I had on hand. I used a PIC16f84a, five red 3mm leds, a photo-interrupter, scrap aluminum and plastic, an old dvd-r 50 pack case, and finally an old motor. I decided to use a slip ring to transfer power to the rotating electronics. The interesting thing is that I only used one contact that connects to the bottom via a "cat wisker" wire (for Vcc), while using the entire metal motor casing, shaft, and aluminum base as the ground (this simplifies the mechanics a lot). The entire thing is powered by a 3.7V lithium polymer battery. I realize that it is rather ugly, but I consider it a success due to the fact that I completed it in a few hours and had all the parts already on hand. Next time I plan on making a much nicer POV clock/display (have to wait until I get a break from classes). Enjoy.