You could easily have a digital camera record stop-frame animation.
All you'd have to do would be:

1. set it in that mode
2. capture a frame 1 sec *after* motion stops
3. wait until there's motion, then go to step 2
4. have a way to exit the mode, and probably trim the last frame(s) which would be due to the user moving the camera to change the mode

I once wrote a program to do this, it worked. This was back when you needed a $500 video acquisition card to capture video.