Electronic Pit Viper

Oh dear.... someone reminded me of Pololu

New since I last looked...

http://www.pololu.com/catalog/product/1061

... an infrared heat sensor, $20

SOMEONE has to make an electronic pit viper!!

If one of these sensors, with suitable optics (not hard) was mounted on a servo controlled rotatong-in-horizontal-plane surface, you could make a "toy" that would seek left-right-left-right... until it saw something hot... i.e. you! And then it would track you.