Introduction
The HC-SR04 Ping Distance Sensor by Giffy Keeler (Kiettisack Internantional School. Vientiane, Laos) This is an electronic sensor commonly used with Arduino microcontrollers as a way to measure distance using sound waves. You will see it used in low cost robots for obstacle detection and avoidance. How does this sensor work? It uses sonar to determine the distance of an object. It does this by: Sending (transmitting) a signal. a high-frequency sound, through the "trig pin". You can't hear it because it is too high for your ears. When the signal (sound) hits an object, it bounces back (reflects) to the HC-SR04, and The transmitter "echo-pin" receives it. If we measure the time it takes for the signal to return, we can determine the distance. Why? Because we know the speed of sound. The speed of sound in dry air at 20 °C = 343 meters/second. So we can use a simple equation to get the distance: distance = (time in seconds/2) * 343 meters ...