How can a motion sensor see me if it's pitch black?

We have motion sensors in some of the rooms in our house that turn the lights on and they can see my movement even if the door is shut and there are no windows. Can can they see me moving?How can a motion sensor see me if it's pitch black?Motion sensors typically don't operate in the visible light spectrum. A typical motion sensor uses infrared sensors which detects body heat, so you don't need light. More sophisticated active motion sensors sends out a signal and measures the reflection, so again, no light is required.How can a motion sensor see me if it's pitch black?
Motion sensor don't detect by seeing people. They detect people by motion of people(movement)How can a motion sensor see me if it's pitch black?Many use infrared to detect motion.How can a motion sensor see me if it's pitch black?
They don't "see" -- they monitor movement.How can a motion sensor see me if it's pitch black?Some of the older motion sensors used sound.