Problem: Two single user bathrooms - in a dorm style house - are shared by multiple people, but the bathroom doors are not visible from the main hallway. This results in many failed trips down the hallway, only to find the one containing all of your toiletries or both (depending on what the need may be) are already occupied.
Solution: A centrally located visual indicator to convey the use status of the bathrooms.
Step 1: Inputs - Detecting Door Status
Inductive proximity switches sense objects by generating a magnetic field. When a metal object reaches a certain distance from the sensors head, it will open or close a circuit (depending on the model). By placing a screw in the door, the sensor can be triggered when the door is closed.