Build a Room Occupancy Tracker with ESP32 and Ultrasonic Sensors

I’ve been tinkering with smart home automation for years, always looking for clever ways to make my home more responsive. Commercial room occupancy sensors work fine, but they’re expensive and often limited in functionality. After one too many instances of my smart lights turning off while I was still reading in my favorite armchair, I decided to build my own room occupancy tracker using an ESP32 and ultrasonic sensors. The beauty of this approach?