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Learn how to use the BMT HC-SR04 ultrasonic sensor in electronics projects. Explore specs, wiring, troubleshooting, and tips for South African makers.
Ideal for robotics, tank level, and automation projects needing accurate proximity data.
Popular, locally available sensor with simple wiring and example code for rapid prototyping.
Includes pinouts, example calculations, and troubleshooting tips for common project snags.
The BMT Ultrasonic Sensor HC-SR04 is a cost-effective, widely compatible distance measurement module. Its ease of use, combined with reliable 2cm-400cm detection range, makes it a favourite in South African classrooms, robotics clubs, and automation prototypes. The sensor uses ultrasound pulses to measure distance to solid objects, outputting a timing signal to microcontroller boards such as Arduino, ESP8266, or Raspberry Pi.
Key project uses include:
Supplied by BMT and stocked at Communica, the HC-SR04 is a solid go-to, supported by extensive online resources and code libraries-suitable for both beginners and advanced users.
| Parameter | Typical Value | Notes |
|---|---|---|
| Operating Voltage | 5V DC | Standard for many dev boards |
| Range | 2cm-400cm | Best accuracy: 2-80cm |
| Accuracy | ±3mm | Good for most hobby tasks |
| Interface | 4-pin (VCC, Trig, Echo, GND) | Digital pulse out |
| Supply Current | 15mA (typ.) | Low power consumption |
| Sensor Angle | 15° cone | Detects within narrow field |
Wiring the HC-SR04 to a microcontroller or single-board computer is straightforward. Typical 4-pin header connection:
| Pin | Label | Connection |
|---|---|---|
| 1 | VCC | 5V Power rail |
| 2 | Trig | Digital Output (MCU pin) |
| 3 | Echo | Digital Input (MCU pin) |
| 4 | GND | Ground/0V |
Below is a typical wiring diagram for Arduino (text/table-based):
[HC-SR04] [Arduino UNO] VCC ----------> 5V Trig ----------> D9 Echo ----------> D10 GND ----------> GND
The sensor emits an ultrasonic pulse and times the echo; distance is calculated using:
Distance (cm) = (Echo pulse width in s) / 58
For example, if Echo is high for 1500 microseconds:
This simple calculation is supported by available Arduino libraries, letting you focus on project logic.
Explore related products such as proto boards, header wires, and compatible Arduino clones in Sensors & Modules and Robotics & Prototyping.
Free shipping for orders over ZAR 1,000.00.
Get a full refund if you had the product for less than 7 days.
Nationwide delivery within 2 - 4 working days.
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