HC-SR04 Ultrasonic Distance Sensor Module

HC-SR04 Ultrasonic Distance Sensor Module

The HC-SR04 Ultrasonic Distance Sensor is a popular and reliable sensor used to measure distance without physical contact. It works by transmitting ultrasonic sound waves and calculating the time taken for the echo to return after hitting an object. Due to its accuracy, low cost, and simple interface, it is widely used in robotics, automation, and IoT projects.

Working Principle

The HC-SR04 uses ultrasonic waves at 40 kHz. When a short trigger pulse is sent to the sensor:

1. The transmitter (T) emits ultrasonic waves.

2. These waves travel through the air and reflect off an object.

3. The receiver (R) detects the reflected echo.

4. The sensor outputs a pulse whose duration is proportional to the distance.

5. Distance is calculated using the time of flight of the sound wave.

Key Features

• Non-contact distance measurement

• High accuracy and stable performance

• Compact and lightweight module

• Low power consumption

• Easy interface with microcontrollers

• Cost-effective solution

Technical Specifications

• Operating Voltage: 5 V DC

• Operating Current: ~15 mA

• Measuring Range: 2 cm – 400 cm

• Measuring Angle: ~15°

• Frequency: 40 kHz

• Resolution: ~3 mm

• Output Type: Digital pulse

Pin Configuration

• VCC: 5 V power supply

• Trig: Trigger input pin

• Echo: Echo output pin

• GND: Ground

Distance Calculation Formula

Distance (cm)=Echo Time (µs)×0.0342\text{Distance (cm)} = \frac{\text{Echo Time (µs)} \times 0.034}{2}Distance (cm)=2Echo Time (µs)×0.034​

Applications

• Obstacle detection robots

• Distance measurement systems

• Smart parking systems

• Water level monitoring

• Automatic doors

• Industrial automation

• Arduino, ESP32, Raspberry Pi projects

Advantages

• Accurate and contactless sensing

• Works in low-light or dark environments

• Simple hardware and software interface

• Long operational life

• Widely supported with example codes

Conclusion

The HC-SR04 Ultrasonic Distance Sensor Module is an efficient and dependable solution for measuring distance in various electronic applications. Its simple working principle, good accuracy, and compatibility with popular microcontrollers make it a preferred choice for students, hobbyists, and professionals working on robotics and automation projects.