The HC-SR04 ultrasonic distance sensor module is a reliable and easy-to-use solution for non-contact distance measurement in robotics and automation projects. Using 40 kHz ultrasonic sound waves, the module accurately measures distances from 2 cm to 400 cm with typical precision up to ±3 mm. It integrates both transmitter and receiver functions, making it compact and efficient for embedded systems. The module operates on a simple principle: a 10 μs trigger pulse initiates measurement, after which the sensor emits ultrasonic waves and listens for the reflected signal. The duration of the returned echo pulse corresponds directly to the measured distance. Designed for compatibility, the standard 4-pin interface (VCC, TRIG, ECHO, GND) allows seamless integration with common microcontrollers, including Arduino-compatible boards. It supports both 5V and 3.3V systems (with appropriate level shifting if required). With low power consumption (approx. 15 mA) and a focused beam angle of approximately 15 degrees, the HC-SR04 is suitable for continuous, real-time detection tasks. This complete kit includes mounting brackets, screws, jumper wires, and a reusable storage case, making it ideal for both prototyping and long-term projects. Important: This module operates using ultrasonic sound waves and does not include any wireless or radio frequency (RF) communication functionality.