Ultrasonic HCSR04 Sensor Library and ROS 2 Wrapper

This repository provides a library and a ROS 2 wrapper for using the HC-SR04 ultrasonic sensor with a Raspberry Pi 3B+.

Introduction

The HC-SR04 ultrasonic sensor is a popular choice for measuring distances using ultrasonic waves. This repository offers a library that allows you to interface with the sensor on a Raspberry Pi 3B+. It also provide a ROS 2 wrapper that makes it easy to integrate the sensor data into your ROS 2 applications.

Library

The library provided here offers low-level access to the HC-SR04 sensor for Raspberry Pi 3B+. It includes functions for reading distance and velocity measurements (veocity computed as difference in time between 2 distance measurements). You can use this library in your non-ROS applications or as a foundation for ROS-based projects.

ROS 2 Wrapper

The ROS 2 wrapper simplifies the integration of the HC-SR04 sensor with ROS 2 Humble. It creates ROS 2 topics to publish distance and velocity data, allowing you to utilize the sensor in your ROS 2 robotic systems.

Prerequisites

To use the provided library and ROS 2 wrapper, you'll need:

• A Raspberry Pi (3B+).
• The HC-SR04 ultrasonic sensor.
• ROS 2 Humble installed on your Raspberry Pi.
• WiringPi library to be installed on your Raspberry Pi (clone using this repository and build it with: cd ~/WiringPi/WiringPi && ./build).

Usage

1. Clone this repository to your Raspberry Pi:

   git clone https://github.com/mataruzz/libHCSR04.git

2. Build and source the wrapper:

   cd libHCSR04/libHCSR04_ros
   colcon build --symlink-install --parallel-workers 2 --executor sequential
   . install/setup.bash

3. Run the ultrasonic HC-SR04 wrapper:

   ros2 run lib_hcsr04_ros RunUltrasonicHCSR04Wrapper 

Reference

• http://wiki.ros.org/Drivers/Tutorials/DistanceMeasurementWithUltrasonicSensorHC-SR04Cpp