I made this fish feeder robot when I was 12. It won Champion at the County Fair through 4-H and got a purple ribbon (the highest award available) at the Minnesota State Fair.
R.U.F.F. is a LEGO Mindstorms robot designed to feed my fish while I'm on vacation. R.U.F.F. stands for Robotic Unattended Fish Feeder. R.U.F.F. is built to sit on top of a 2 gallon fish tank. It shakes fish food flakes into the tank once each day. R.U.F.F. raises a flag after the fish have been fed to let everyone know that the fish have been fed. After 12 hours R.U.F.F. lowers the flag.
R.U.F.F. will also feed the fish on command. You simply touch the orange button on the main control unit. R.U.F.F. knows not to feed the fish again that day.