HC-SR04 is a non-contact distance measurement module, it provides high accuracy and high-resolution ultrasonic proximity detection and ranging in the air. This ultrasonic sensor detects objects from 2 cm to 4.5meters.
Specifications:
4 pins
Power supply: 5V DC
Static current: 2mA
Sensor angle: 15 to 35 degrees
Sensing distance: 0.75in (2cm) to 13ft (4m)
More precise measurements with ranges up to 6.5ft (2m) away