The catbot was inspired when I took care of a friends overly needy cat. It sweeps the sensor to find human temperature object and then drags itself towards them. The sensor is an Eltec Pyroelectric sensor that I got from Acroname. The brain is an OOPic with an hbridge on it to control the motors. The shell is 1/4" lexan with a steel frame mig welded out of 1/4" round. I'm hoping it won't die if someone steps on it since the point is for it to get under your feet.