Fun with Arduino 38 Ultrasonic Distance Measurement with HC-SR04
The HC-SR04 is a nice little less than $1,- device that can be used to measure distance. It contains a loudspeaker and a microphone. When we send a pulse to its trig input, it will output an ultrasonic (40kHz) sound burst. It then measures the time it takes for the echo to return. We can […]