There is a list of resources for building bathroom occupancy detector:
- https://kig.re/2014/10/12/borat-bathroom-occupancy-wireless-detection-and-notification-with-arduino.html
- https://robots.thoughtbot.com/arduino-bathroom-occupancy-detector
- http://bathroom.mit.edu/index.html?1505961561
- https://github.com/jelder/doors
- https://github.com/adam-p/arduino-bathroom-indicator
- https://www.stavros.io/posts/control-rf-devices-with-arduino/