HC-SR04 Ultrasonic Distance Measuring Sensor Module
Key Features
Model: HC-SR04 Ultrasonic Distance Sensor
Detection Principle: Ultrasonic High-Frequency Sound Waves
Operating Voltage: 5V DC
Measurement Range: 2 cm to 400 cm (with 3mm accuracy)
Trigger Interface: 2-Pin control layout (Trigger & Echo pulses)
The HC-SR04 calculates distance by transmitting a 40 kHz sonic burst and timing how long it takes for the echo to bounce back off an object. It is a fundamental sensor used to give autonomous robot cars obstacle-avoidance capabilities.