If you're away on holidays, or you just have to work late, you don't have to worry about your pets going hungry at home. This Raspberry Pi-controlled pet feeder lets you take care of your pets on demand.
You'll need a thorough understanding of electronics to do this on your own, but the payoff is awesome. The Raspberry Pi receives an email over Wi-Fi and hooks into the main PCB of the feeder over its GPIO pins to trigger a feeding. It even incorporates a basic webcam to send you proof that your pets are fed and happy. If you want to try it yourself, check out the source link.
Frankenfeeder [Lots of Cool Geeky Things]