"I know the DIY VCR cat feeder article has been popular - when I went on vacation, it was something I considered to help keep me the cats entertained and fed. They were formerly strays, so an "all you can eat" bucket would turn them into 100lb behemoths in about 30 seconds :-) Unfortunately, the VCR version requires some complex mechanical pieces, so I opted instead for a computer / cardboard mashup."
http://www.makezine.com/blog/archive/2006/08/ubuntu_linux_controlled_diy_ca.html?CMP=OTC-0D6B48984890