Probably best specified video I've found :)

Nice video! Although I would personally put a diode in the circuit to protect de RPI from power going back to it. But still a nice video, thanks!

How about this: my cat's litter box is in the same room as my desktop computer (no other place). I hook up a camera to a raspberry pi, and using a motion sensor, some number of seconds after my cat is done, the pi would tell a mains power filter/fan to run for a set amount of time?

Mèsi