[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 ...

Last year, I took a look at some mostly low-cost passive infrared (PIR) motion sensor modules. Then recently, I became more aware of cheap microwave radar motion sensor modules. The popular version of ...

SwitchBot has announced a new product called the Presence Sensor with mmWave Radar. This sensor is built to detect people in ...

(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 ...