HC-SR04 Ultrasonic Ranging Module Sonar Sensor

HCSR04 is an Ultrasonic ranging module which consists of a transmitter,receiver and control circuit. It has four pins for VCC, GND, Trigger and Echo.You can easily interface it with micrcontrollers and Arduino boards.

The basic principle of work is:

• Using IO trigger for at least 10us high level signal,
• The Module automatically sends eight 40 kHz and detect whether there is a pulse signal back.
• IF the signal back, through high level , time of high output IO duration is the time from sending ultrasonic to returning. Test distance = (high level time×velocity of sound (340M/S) / 2