Motion sensors have pyroelectric sensors that detect infrared radiation. When a warm object, such as a human, moves within the sensor's range, it causes a change in the infrared levels, triggering the sensor.

The detection range typically varies between 5 to 7 meter, depending on the environmental conditions.

No, Motion sensors cannot detect motion through walls as they rely on detecting infrared radiation, which does not pass through solid objects.

Yes, Motion sensors work in the dark because they detect infrared radiation, which is independent of visible light.