hey there, im thinking of building an electronic cat toy, i dont really know where to begin, think i want to make something you can hang on a wall or something and plug in or use batteries, batteries would probably be best, and i want it to go on when the cat walks in front of it or something, so maybe some kind of sensor and a motor, just dont really know what i should do, i kinda want to keep it simple, so if anyone has any ideas, let me know. thanks!