An ultrasonic sensor measures distance by sending a high-frequency sound pulse and measuring how long the echo takes to return.
The sensor has a transmitter and receiver. The transmitter sends a short sound burst. If an object is in front of it, the sound bounces back as an echo.
The controller measures the travel time. Since sound speed is known, the distance can be calculated from the echo time.
The microcontroller sends a short trigger signal to start the measurement.
The sensor sends ultrasonic sound waves forward through the air.
The receiver detects the sound after it reflects from an object.
Distance is found from time and speed of sound, then divided by two because the sound travels out and back.
Obstacle avoiding robots, parking sensors, water-level measuring systems, smart dustbins, and distance measuring tools.