The sensor faucet is based on the principle of infrared reflection. When a human hand is placed in the infrared region of the faucet, the infrared ray emitted by the infrared ray tube is reflected by the human hand to the infrared ray receiving tube, and is processed by the microcomputer in the integrated circuit. After being sent to the pulse solenoid valve, after receiving the signal, the solenoid valve opens the valve core according to the specified command to control the water output of the faucet; when the human hand leaves the infrared sensing range, the solenoid valve does not receive the signal, and the solenoid valve spool is reset by the internal spring. Control the faucet.