I needed a self feeder for my cat, so he would stop waking me up. After looking around on the Net (and instructables) I did find one that I based this feeder on, in a book called (Snowball Launchers, Giant-Pumpkin Growers, and Other Cool Contraptions by Tom Fox) I take no credit for it. Just didn’t like the idea of using cardboard. I also wasted a lot of time trying to use electric motors and timers. This was a much better idea and has been working well so far.