HC-SR04 Ultrasonic Range Finder Sensor Module

HC-SR04 Ultrasonic Range Finder Sensor Module

The HC-SR04 Ultrasonic Range Finder Sensor Module is a popular and reliable distance-measuring sensor used in robotics, automation, and Arduino projects. It uses ultrasonic waves to determine the distance between the sensor and an object with high accuracy and fast response time. Operating at 5V, it provides stable readings over a range of 2cm to 400cm with excellent precision.

This module features Trigger and Echo pins for easy interfacing with Arduino, Raspberry Pi, ESP8266, ESP32, and other microcontrollers. Its low power consumption and compact design make it ideal for obstacle detection, smart vehicles, level measurement, proximity detection, and DIY electronics projects.

Features

• Distance measurement range: 2cm to 400cm
• Operating voltage: 5V
• Accurate and stable readings
• Convenient 4-pin interface (VCC, Trig, Echo, GND)
• Wide 15° detection angle
• Suitable for Arduino, Raspberry Pi & microcontrollers
• Ideal for robotics, automation & DIY electronics

Applications

• Obstacle detection in robots
• Autonomous vehicles & smart car projects
• Distance and proximity measurement
• Water level and tank level monitoring
• Object avoidance systems
• Smart dustbins (automatic lid opening)
• Security and intruder detection systems
• Industrial automation
• Parking sensor systems
• IoT-based measurement projects
• Ultrasonic-based counters and detectors
• Smart agriculture automation
• Home automation projects
• DIY electronics and Arduino learning projects

HC-SR04 Ultrasonic Range Finder Sensor Module offers precise distance measurement from 2cm to 400cm. Ideal for Arduino, robotics, obstacle detection, and automation projects.

Frequently Asked Questions (FAQ)

1. What is the HC-SR04 Ultrasonic Sensor?

The HC-SR04 is an ultrasonic distance sensor that measures the distance to an object using sound waves. It provides accurate measurements from 2cm to 400cm.

2. How does the HC-SR04 sensor work?

It sends an ultrasonic pulse through the Trigger (Trig) pin and receives the reflected wave through the Echo pin. The time taken for the echo is converted into distance.

3. What is the operating voltage of the HC-SR04?

The sensor operates at 5V DC, making it fully compatible with Arduino and most microcontrollers.

4. Can I use the HC-SR04 with Arduino?

Yes, the HC-SR04 is widely used with Arduino, ESP8266, ESP32, Raspberry Pi, and other microcontrollers.

5. What is the maximum range of the HC-SR04?

It can measure distances up to 400 cm (4 meters) under optimal conditions.

6. What is the minimum measurable distance?

The minimum sensing distance is 2 cm.

7. Is the HC-SR04 waterproof?

The standard HC-SR04 is not waterproof. For outdoor or wet environments, use the JSN-SR04T waterproof ultrasonic sensor.

8. What accuracy can I expect from the sensor?

The HC-SR04 typically provides accuracy within ±3 mm.

9. What is the measuring angle of the sensor?

It has a 15-degree detection angle, suitable for focused distance measurement.

10. Does the HC-SR04 require any special libraries?

No specific library is required, but many ready-made Arduino libraries are available for easier coding.

11. Can the HC-SR04 detect transparent or soft objects?

Performance may reduce for soft, angled, or sound-absorbing materials, as they may not reflect ultrasound effectively.

12. What are common applications of the HC-SR04 sensor?

Robotics, obstacle detection, smart dustbins, distance measurement, home automation, parking systems, and IoT devices.

13. How do I connect the HC-SR04 to Arduino?

Use four pins: VCC → 5V, GND → GND, Trig → Digital Pin, Echo → Digital Pin. Most example codes use pins 9 and 10.

14. Do I need a resistor divider for the Echo pin?

For Arduino UNO you can connect Echo directly (5V logic).
For ESP8266 / ESP32 (3.3V) use a voltage divider on the Echo pin.

15. What is the pulse width of the Echo signal?

The Echo pin outputs a pulse proportional to the distance.
Formula: Distance (cm) = Echo time (µs) / 58

16. Can HC-SR04 measure through glass?

No, ultrasonic waves do not pass well through glass, plastic sheets, or sealed enclosures.

17. Why is my sensor giving unstable readings?

Possible causes:

• Electrical noise

• Object too close or too far

• Soft/angled surfaces

• Sensor not facing object straight

• Poor wiring or loose connections

18. What is the typical response time?

The HC-SR04 can take readings approximately every 60ms, giving a fast response.

19. Can the HC-SR04 measure liquid levels?

Yes, it can measure liquid levels from above, such as in water tanks, but it should not be exposed to moisture.

20. Does the HC-SR04 work outdoors?

It can work, but it is not waterproof. Use a waterproof version for outdoor/rainy environments.

21. What microcontrollers support HC-SR04?

It works with:

• Arduino UNO, Nano, Mega

• ESP8266, ESP32

• Raspberry Pi (via GPIO)

• STM32

• PIC/AVR

22. What is the frequency of the ultrasonic wave?

The HC-SR04 operates at 40 kHz.

23. Does it consume a lot of power?

No, typical current consumption is 15 mA, very low for battery-powered projects.

24. Can multiple HC-SR04 sensors be used together?

Yes, but ultrasonic waves may interfere. Use:

• Different firing times

• Delays between sensors

• Physical separation

25. What is the lifetime of the HC-SR04?

With normal use, the sensor lasts several years, as it has no moving parts.

26. Does the HC-SR04 need calibration?

Out of the box, it doesn’t require calibration, but you can fine-tune timing in software for improved accuracy.