Best Presence

The Athom Human Presence Sensor is a compact mmWave radar occupancy sensor that ships with ESPHome, the open-source firmware platform, preinstalled. Where a PIR motion sensor sees only movement and marks a room empty the moment you sit still, millimeter-wave radar detects micro-movements like breathing and typing, so lights stay on while you are actually present. The hardware pairs an ESP32-class Wi-Fi microcontroller with an LD2410-family radar module, the same combination behind most of the DIY presence-detection builds in the Home Assistant community, except here it arrives assembled, cased, and flashed, typically for around twenty dollars.