detector

A safety device that detects the presence of smoke, acting as an indicator of fire.

An electronic instrument that detects the presence of metal nearby.

A device that measures physiological responses to determine if a person is telling the truth.

A device that detects moving objects, particularly people, often used in security systems.

A device used in vehicles to detect the radio waves from a police radar gun.

An instrument used to detect the presence and intensity of ionizing radiation.

A vehicle equipped with detection equipment, especially for finding unlicensed television receivers.