I built a toilet occupancy light for the office. We had a long office with a single toilet, so built a battery powered closed-door detector on one side, and a m

I built a toilet occupancy light for the office. We had a long office with a single toilet, so built a battery powered closed-door detector on one side, and a mains-powered sign that indicated whether the toilet was free or not. Very reliable, ESPHome was never an issue. This was circa 2018.