Well you'll need a motion sensor (you could use two for depth perception and direction of movement) and a camera on a rotating gimble. You'll need to look at the motion sensor's data sheet to see what kind of output will be transmitted for certain responses. And all you'll need to do is code a response to the gimbal to turn the camera is certain ways depending on the inputs from the infra red sensor. The only issue is working out away to adjust the motor/gimbal to the degree of your movement but thats mostly trial an error- or math ;(,
if you use an arduino uno, the programming for it is relatively straight forward.
Hopefully this has helped but feel free to ask anything else?