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.

(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 ...

Add Popular Science (opens in a new tab) Adding us as a Preferred Source in Google by using this link indicates that you would like to see more of our content in Google News results. Get the Popular ...