HC-SR04 Ultrasonic Sensor for Arduino

How it Works

1. Trigger: A 10µs high-level (TTL) pulse is sent to the Trig pin.
2. Transmit: The sensor emits eight 40kHz ultrasonic bursts.
3. Receive: The Echo pin goes high when the signal starts and stays high until the echo returns.
4. Calculate: The time the Echo pin is high (pulse width) is measured by the microcontroller, which calculates distance using the speed of sound (Distance = Speed × Time / 2).

Key Specifications

• Voltage: 5V DC
• Range: 2cm – 400cm (2 inches – 13 feet)
• Accuracy: Up to 3mm
• Frequency: 40kHz
• Angle: < 15 degrees
• Pins: VCC, GND, Trig, Echo

Common Applications

• Obstacle Avoidance in Robots
• Motion Detection
• Level Sensing
• Interactive Art Projects
• Automation Systems