How does a motion detector work?

Will it detect motion through a glass window?How does a motion detector work?No it will not, Most motion detectors (for alarm systems) are passive infrared, they do not detect through glass or walls, They basically detect changes in temp. How does a motion detector work?There are also dual technology types which utilise both (PIR) infra-red detectors and microwave for fool proof detection without false alarms.

To protect windows you will need double or triple knock vibration detectors which can be wired or work on RF (wireless).

Motion detectors (PIR) operate on the principle of temperature changes across the sensor; a person walking across the room indicates suddenly (moving) temperature change. An open window will trigger also as this is a sudden change in temperature.

Sensors do not respond to very slow movement or very quick movement (fly) across the field.

CH temperature change is very gradual and stationary thus the heat source does not move across the fiels as a body would.