ULTRASONIC SENSOR HC-SR04

The HC-SR04 Ultrasonic Sensor is a low-cost, non-contact distance measurement sensor that uses ultrasonic sound waves to detect the distance between the sensor and an object. It operates by transmitting a 40 kHz ultrasonic pulse and measuring the time taken for the echo to return, allowing accurate distance calculation. The sensor typically measures distances from 2 cm to 400 cm with good accuracy and is easy to interface with microcontrollers such as Arduino, ESP32, STM32, Raspberry Pi, and PIC. Due to its reliable performance and simple operation, the HC-SR04 is widely used in obstacle detection, robotic navigation, parking assistance systems, water level monitoring, and industrial automation applications.