The HC-SR04 Ultrasonic Distance Sensor is a popular, low-cost module for measuring distances using sound waves. It works by emitting ultrasonic waves and measuring the time it takes for the echo to return, allowing precise distance measurement without physical contact.
This sensor is perfectly compatible with Arduino, ESP32, Raspberry Pi, and most microcontroller boards. Widely used in robotics, obstacle detection, object tracking, smart parking systems, and distance measurement projects.