The HC-SR04 Ultrasonic Sensor is a widely used non-contact distance measurement module designed for accurate object detection using ultrasonic waves.
It operates by emitting a high-frequency ultrasonic pulse (40 kHz) and measuring the time it takes for the echo to return from an object. This allows precise calculation of distance, making it ideal for Arduino, robotics, automation, and IoT applications.
With its simple 4-pin interface (VCC, Trig, Echo, GND) and reliable performance, the HC-SR04 is one of the most popular sensors in the electronics market.
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Key Features
• Non-Contact Distance Measurement
• Measurement Range: 2cm to 400cm
• High Accuracy (±3mm typical)
• Simple 4-Pin Interface
• Low Power Consumption
• Stable and Reliable Performance
• Compatible with Arduino, ESP32, Raspberry Pi
• Compact and Easy to Integrate
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Technical Specifications
• Operating Voltage: 5V DC
• Working Current: ~15 mA
• Ultrasonic Frequency: 40 kHz
• Measuring Range: 2 cm – 400 cm
• Accuracy: ±3 mm
• Trigger Input Signal: 10 µs TTL pulse
• Echo Output Signal: TTL pulse proportional to distance
• Interface Pins: VCC, Trig, Echo, GND
• Operating Temperature: -15°C to +70°C
• Dimensions: approx. 45 × 20 × 15 mm
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How It Works
The sensor sends an ultrasonic pulse and measures the return time:
• Speed of sound ≈ 343 m/s
• Divide by 2 because the signal travels to the object and back
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Key Advantages
• Accurate and reliable distance measurement
• No physical contact required → safe for objects
• Easy to program and integrate
• Low cost with high performance
• Widely supported with libraries and tutorials
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Typical Applications
• Obstacle avoidance robots
• Parking assistance systems
• Distance measurement devices
• Smart home automation (presence detection)
• Liquid level monitoring
• Security and alarm systems
• Industrial automation sensing