What is Passive Infrared Detection

Question

What does "Passive Infrared (PIR) Detection" mean?

Answer

"Passive infrared detection" is basically the detection of a change in temperature, often from body heat. If someone walks into an area protected by a sensor with Passive Infrared (PIR) Detection, then their body heat is detected, and the sensor is triggered. When the temperature is returned to its normal level, the motion sensor resets.