What is a PIR motion sensor?

All objects emit energy in the form of invisible infrared radiation. A passivePassive infraredInfrared (PIR) sensor detects movementchanges in the levels of infrared-emittinginfrared sourcesradiation within its field of view. ThisWhen allowsa it to sense when anwarm-bodied animal passes in front.front of the sensor, the amount of infrared energy detected shifts, allowing the sensor to register movement.

The term “passive” refers to the fact that the sensor does not emit any radiation butitself—it insteadsimply monitors the levels if infrared radiation fallingnaturally onemitted it.by Asobjects ain result,its surroundings. This makes PIR sensors are veryextremely energy-efficient.efficient and reliable for long-term use in the field.

In a camera-trap setup, the PIR sensor’s role is to detect an animal’s presence and automatically trigger the connected photographic equipment, such as a DSLR or mirrorless camera and flashes. This enables the capture of high-quality images of wildlife with minimal human disturbance.