ELEGOO 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.
Ultrasonic Sensor HC-SR04 is great for all kinds of projects that need distance measurements, avoiding obstacles as examples. HC-SR04 provides 2cm-400cm non-contact measurement function, the ranging accuracy can reach to 3mm. The modules include ultrasonic transmitters, receivers, and control circuits.