Sonar Sensor HC SR04

How It Works: The Time-of-Flight Principle

The HC-SR04 consists of an ultrasonic transmitter, a receiver, and a control circuit. When triggered by a 10µs pulse, the transmitter sends out an 8-cycle burst of ultrasound at 40kHz. These waves travel through the air, bounce off an object, and return to the receiver. The “Echo” pin then outputs a high-level pulse whose duration is proportional to the time taken for the round trip. At RoboShop BD, we recommend this sensor for its immunity to sunlight and black-material interference, which often plagues infrared-based distance sensors.

Reliable and Easy to Interface

This sensor is remarkably easy to use with any microcontroller, including Arduino, ESP32, and Raspberry Pi. Because it operates on a standard 5V supply and consumes less than 15mA, it can be powered directly from your development board. Its compact, “two-eyed” design has made it a favorite for the global maker community, ensuring a vast library of open-source code and tutorials are available for your next build.

Key Features

• Non-Contact Measurement: Detects objects without physical touch, preventing damage to delicate surfaces.

• High Precision: Offers a resolution of 0.3cm and a ranging accuracy of up to 3mm.

• Wide Detection Range: Reliable sensing from as close as 2cm up to 4 meters away.

• 4-Pin Interface: Simple wiring with VCC, Trig, Echo, and GND pins.

• Sunlight Independent: Unlike IR sensors, its performance is not affected by ambient light or dark-colored objects.

• Fast Response: High-speed measurement cycles (suggested >60ms) for real-time robotics.

Technical Specifications

Pinout Configuration