HC-SR04 Ultrasonic Sensor is a device that can measure the distance to an object by using sound waves. It measures distance by sending out a sound wave at a specific frequency and listening for that sound wave to bounce back. By recording the elapsed time between the sound wave being generated and the sound wave bouncing back, it is possible to calculate the distance between the sonar sensor and the object. Themodule works: (1) IO trigger ranging to at least 10us high signal; (2) module automatically sends eight 40kHz square wave, automatically detect whether a signal return; (3) the signal to return, a high IO output, high duration of Ultrasonic time from launch to return. Test distance = (time high * speed of sound (340M / S)) / 2; Technical Specification: Power Supply :+5V DC Quiescent Current : 3mA Working Current: <5mA Effectual Angle: <15° Ranging Distance : 2cm - 450 cm Resolution : 0.3 cm Measuring Angle: 30 degree Note: The module should be inserted Fortunately, the circuit board re-energized, and avoid the high malfunction, if they have re-energized before they solve.

?Test mode ?:Test distance = ((Duration of high level)*(Sonic :340m/s))/2. ?Effectual Angle?: <15°. ?Ranging Distance?:2cm - 450 cm;High precision: 0.3 cm. Working Voltage?: 5V DC;Quiescent current: less than 2mA. ?HC-SR04 Ultrasonic Sensor?:This is a device that can use sound waves to measure the distance of an object. It measures distance by emitting a sound wave of a specific frequency and listening to the bounce of that sound wave. The distance between the sonar sensor and the object can be calculated by recording the time elapsed between the generation of the sound wave and the bounce of the sound wave.