Today I dismantled a Hard disk drive. I found the spindle motor has three contacts; therefore I suspect its a 3 phase bi-polar stepper motor. I will over time use this inside a small head (perhaps a dolls head), together with the passive infra-red detectors found in PIRs for burglar alarms, to detect and then follow a human entering a room. If anyone has some circuit suggestions I'm all ears (not literally!) (firstname.lastname@example.org).
At present I am building CYBOT a `Real Robots' magazine kit. I have saved the parts from several issues so that I can have a building spree and see something movable, that way I keep the enthusiasm going (at least that's my theory).