HC-SR04 Ultrasonic Sensor

The HC-SR04 Ultrasonic Sensor is a popular and affordable module used for non-contact distance measurement. It operates on the principle of sonar, transmitting an ultrasonic wave at 40kHz which reflects off an object and returns to the sensor. The module calculates the time interval between sending and receiving the signal to determine the distance with an accuracy of up to 3mm. It consists of an ultrasonic transmitter, receiver, and control circuit, making it a complete solution for distance sensing needs. Key features include a wide measuring range of 2cm to 400cm, a narrow measuring angle of approximately 15°, and simple Trigger and Echo interface logic compatible with 5V microcontrollers like Arduino. Common applications include obstacle avoidance in robots, vehicle parking sensors, industrial distance monitoring, and liquid level detection. This sensor is chosen for its reliability, ease of use, and excellent performance-to-price ratio, making it a staple component for hobbyists, students, and engineers in various electronic projects.