Reflecting the newest wave of technology, automatic faucets or Sensor Faucets are battery operated, automatic bathroom fittings. The automatic or sensor faucet uses multiple infrared sensors to tell whether an object is in front of it. If an object moves in front of the beam, it reflects the beam back to its original point. Then, once the beam hits the sensors, the faucet turns on. Most of the electric faucets are set with an automatic timer, so after it's triggered, it stays on for a certain period of time.