PIR

PIR sensors detect occupancy via infrared heat, or micro-movement in radar variants, to trigger lighting, alarms or HVAC.

Classic PIR reacts to a moving heat source and can miss a still person; mmWave radar keeps detecting someone sitting still. Multi-sensor units add temperature, humidity and lux on one radio.

• Technology — PIR for simple motion triggers, mmWave radar for continuous presence
• Protocol — Zigbee for mesh hubs, Wi-Fi for standalone setups
• Mounting — 230 V, USB-C or battery, depending on ceiling, wall or corner placement