So I came up with two ideas: one is for car keys and the other a trash can:
The car keys prevent you from forgetting to lock your car. They send a wireless signal once all the doors are closed, The key is outside of the car, and he orientation of the key has changed for 3 seconds. Once The car is locked the keys turn green for a second, like a heartbeat, so that you know for sure that the car is locked.
The trash can is simply a can placed every couple of blocks: on any “trash block” there is a track with hand sensors in it. These sensors are able to detect the difference between a hand and anything else, and send the trashcan straight to your location. Kinda fun I think 
both were done in under 15 minutes… should be working on my final drawing project, figured i’d take a break with this though. It was fun!
