The HC-SR04 Ultrasonic Distance Sensor Module is a high-precision ranging device designed for non-contact distance measurement. It operates by emitting ultrasonic waves and measuring the time delay of their reflection to determine distance with high accuracy. The module features a measuring range of 2 cm to 400 cm with a typical accuracy of ±3 mm. It operates at a frequency of 40 kHz and requires a 5 V DC power supply. The HC-SR04 is compatible with microcontrollers such as Arduino, Raspberry Pi, STM32, and ESP32, making it ideal for robotics, obstacle avoidance, and object detection applications.