Recently, I exhausted my stock of common passive infrared (PIR) motion sensor modules and was looking for a new one to play with. I searched the web for a small type with self-contained electronics.

A new motion sensor incorporates micromachined thermal transistors to facilitate human presence and motion detection in security systems, home automation equipment, and Internet of Things (IoT) ...

[ladyada] has a freshly-published and amazingly thorough tutorial on passive infrared (PIR) motion sensors. Most often seen in security floodlights and automatic doors, in creative hands these sensors ...

(Passive InfraRed sensor) A device used to detect motion by receiving infrared radiation. When a person walks past the sensor, it detects a rapid change of infrared energy and sends a signal. PIR ...

Many close-proximity motion detectors use the classic, widely available passive-infrared (PIR) approach, which is effective but has limited sensitivity and adjustability, and can’t “see” through ...