HC-SR04 Ultrasonic Sensor Distance Module: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. | Power Supply:5V DC;Quiescent Current:<2mA;Effectual Angle:<15°;Ranging Distance:2cm~450cm;Resolution:0.3 cm,Module precision:blind spots (2cm)-SUPER CLOSE. | The module performance is stable,measure distance accurately.SRF05,SRF02 ultrasonic ranging module comparable.This module is compatible with GH-311 anti-theft module.