Early IoT human sensing mostly used PIR (Passive Infrared). The moment a person moved, it triggered; the moment they sat down to read, the light went out.
Human presence sensors use 60GHz mmWave (FMCW) to capture micro-motions of the chest from breathing, continuously outputting "occupied" even when static.
The XKC-LD002 from
Shenzhen Xingkechuang Technology Co., Ltd. features a wide detection angle, with static recognition up to several meters, outputting high/low logic levels or serial coordinates. In IoT office nodes: someone present → maintain fresh air/HVAC; nobody for 3 minutes → cut loads. Compared to PIR, energy savings increase by approximately 30%, and it is unaffected by pets or thermal air currents.
This device from Xingkechuang is already used in meeting rooms, bathrooms, and wellness beds, serving as a domestic component-level alternative to Aqara-style Presence Sensors.
