HC-SR04 Ultrasonic Sensor Integration with MicroPython

Overview

This repository provides a lightweight MicroPython implementation for interfacing with the HC-SR04 Ultrasonic Sensor, a widely used device for distance measurement in DIY electronics projects. The code demonstrates how to accurately measure distances using a trigger and echo mechanism and is tailored for efficiency on MicroPython-compatible boards.

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Features

• Simple and lightweight design for easy integration.
• Measures distances with accuracy up to a few centimeters.
• Built-in handling for timeouts to ensure robust measurements.

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Prerequisites

Hardware Required

1. HC-SR04 Ultrasonic Sensor
2. A MicroPython-compatible microcontroller (e.g., ESP8266, ESP32, Raspberry Pi Pico).
3. Jumper wires.
4. Breadboard (optional).

Pin Connections

Sensor Pin	Microcontroller Pin	Description
VCC	5V or 3.3V	Power input
GND	GND	Ground
TRIG	GPIO (e.g., 15)	Trigger signal input
ECHO	GPIO (e.g., 14)	Echo signal output

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Installation

1. Clone the repository:

   git clone https://github.com/SombitPramanik/UL_Sensor_HC_SR04
   cd UL_Sensor_HC_SR04

2. Transfer the UltrasonicSensor class to your MicroPython board. You can use a tool like Thonny or ampy to upload the script.

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Code Example

Usage

from machine import Pin, time_pulse_us
import utime
from HCSR04 import UltrasonicSensor

# Initialize ultrasonic sensor (GPIO pins 14 and 15)
sensor = UltrasonicSensor(trigger_pin=14, echo_pin=15)

while True:
    distance = sensor.measure_distance()
    if distance is None:
        print("Out of range!")
    else:
        print("Distance: {:.2f} cm".format(distance))
    utime.sleep(0.5)

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Class Documentation

UltrasonicSensor

A lightweight class to measure distances using the HC-SR04 sensor.

Initialization

UltrasonicSensor(trigger_pin: int, echo_pin: int)

• Parameters:
  • trigger_pin: GPIO pin connected to the TRIG pin of the HC-SR04.
  • echo_pin: GPIO pin connected to the ECHO pin of the HC-SR04.

Methods

• measure_distance
  Measures the distance in centimeters.
  • Returns:
    • A float value representing the measured distance in cm.
    • None if the echo is not received within the timeout period (30ms).

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HC-SR04 Working Principle

1. Trigger Pulse:
   The sensor sends out a short ultrasonic pulse when a 10-microsecond HIGH signal is applied to the trigger pin.

2. Echo Reception:
   The sensor measures the time it takes for the ultrasonic wave to return after reflecting off an object.

3. Distance Calculation:
   The distance is calculated using the formula:

   Distance (cm)= 2×29.1/Pulse Duration (µs)

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Error Handling

If the echo is not received within the 30ms timeout, the measure_distance method returns None. Ensure the object is within the sensor’s range (2 cm to 400 cm).

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License

This project is licensed under the MIT License. See the LICENSE file for more details.

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Author

Sombit Pramanik

• GitHub: SombitPramanik

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Contributions

Contributions, issues, and feature requests are welcome. Feel free to check out the issues page or submit a pull request.

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Disclaimer

This software is provided "as is", without warranty of any kind. Use it at your own risk.

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