3 Review(s)

Product features: Ultrasonic ranging module hc - sr04 provides 2cm - 400cm non-contact measurement function, the ranging accuracy can reach to 3mm. The modules includes ultrasonic transmitters, receiver and control circuit. The basic principle of work: (1) using io trigger for at least 10us high level signal, (2) the module automatically sends eight 40 khz and detect whether there is a pulse signal back. (3) 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 pin configuration: Pin 1: Vcc(5v) pin 2: Trigger pin 3: Echo pin 4: Gnd.