IR Break Beam Sensor - 3mm LEDs ID: 2167 - $1.95 : Adafruit Industries, Unique & fun DIY electronics
Adafruit Industries, Unique & fun DIY electronics and kits IR Break Beam Sensor - 3mm LEDs ID: 2167 - Infrared (IR) break-beam sensors are a simple way to detect motion. They work by having an emitter side that sends out a beam of human-invisible IR light...