I know it looks super evil, but you should really give i.C. Hexapod (or IC) a chance. IC tracks any face that is near enough for the robot to see. If stared at long enough, it'll take a picture of the face, mark the date and location it was taken, and upload the spoils onto its website.
IC is a fourth generation Hexapod — a line of robot chassis built by engineer Matt Denton. An onboard processor built into the 'bot handles the locomotion of its 21 servos and an additional, external processor takes care of face recognition and tracking. Cool tidbit: If the external processor fails, IC automatically goes to sleep to protect it from any corruption.
Click through to see i.C. Hexapod strut its stuff.