Skip to content

Latest commit

 

History

History
101 lines (81 loc) · 4.97 KB

README.md

File metadata and controls

101 lines (81 loc) · 4.97 KB

microROS with Raspberry Pi and Arduino

This project demonstrates how to use microROS with a Raspberry Pi and Arduino to control LEDs based on messages from a ROS2 publisher. The project explores serial communication between the Raspberry Pi and an Arduino, using microROS-like concepts without relying on the microROS library due to memory limitations on the Arduino Uno.

Project Overview

Key Components:

  • Raspberry Pi running ROS2.
  • Arduino Uno connected to the Raspberry Pi via serial communication.
  • A simple Arduino circuit with LEDs that can be controlled using a pin number received via serial.

Node Structure:

  • arduino_uno_serial node - Handles serial communication with the Arduino Uno, sending pin numbers and receiving responses.
  • arduino_talker node - Publishes random pin numbers (8-12) corresponding to LED control on the Arduino.
  • led_control topic - Used for communication between the arduino_talker node (publisher) and the arduino_uno_serial node (subscriber).

Setup Instructions

Prerequisites

  • A Ubuntu system is recommended for the best compatibility with ROS2.
  • Install ROS2. You can follow the installation instructions here: ROS2 Installation.
  • WSL (Windows Subsystem for Linux) can also be used if you're on a Windows machine. However, note that WSL does not have access to USB drivers by default, so you will need to set up USB access via usbipd (available here: https://github.com/dorssel/usbipd-win).

Folder Structure

The folder structure inside the ros2_ws/src folder:

  • arduino_lister/
  • arduino_talker/
  • arduino_uno_serial/

Clone the repository and move files to ros2_ws/src directory (or create the workspace first):

  • git clone <repository_url> ~/ros2_ws/src
  • sudo mv ~/simple_microROS_arduino/arduino_talker ~/ros2_ws/src
  • sudo mv ~/simple_microROS_arduino/arduino_listener ~/ros2_ws/src
  • sudo mv ~/simple_microROS_arduino/arduino_uno_serial ~/ros2_ws/src

After placing the folders in src/, you need to source ROS2 in your terminal:

  • . install/setup.bash

Building the Packages

Navigate to your ROS2 workspace and build the packages:

  • cd ~/ros2_ws
  • colcon build --packages-select arduino_uno_serial
  • colcon build --packages-select arduino_talker

Running the Nodes Open a new terminal, source ROS2 and run the arduino_talker:

  • cd ~/ros2_ws
  • . install/setup.bash
  • ros2 run arduino_talker arduino_talker_node You should see an output like: image

ros2 run arduino_talker arduino_talker_node In another terminal, source ROS2 again and run the arduino_uno_serial node:

  • cd ~/ros2_ws
  • source install/setup.bash
  • ros2 run arduino_uno_serial arduino_uno_serialized

You should see an output like and the led pins flashing: image

Arduino Circuit The Arduino Uno controls six LEDs based on the pin numbers sent via serial. This extends the basic "blink" LED functionality to support multiple LEDs.

Wiring:

Connect LEDs to pins 8, 9, 10, 11, 12 on the Arduino Uno. Code Breakdown Arduino Code (simplified): The Arduino listens for pin numbers sent over serial and blinks the corresponding LED. ROS2 Publisher Node (arduino_talker):

  • This node generates random pin numbers from 8 to 12 and publishes them to the led_control topic. It uses std_msgs::msg::String for communication. ROS2 Subscriber Node (arduino_uno_serial):

  • This node listens for messages on the led_control topic and sends the received pin number to the Arduino via serial communication. It expects a response and logs it. Example Publisher Code:

    // Publisher node to send random LED pin numbers int random_pick(){ int pins[5] = {8,9,10,11,12}; rclcpp::Clock clock(RCL_SYSTEM_TIME); auto time_now = clock.now(); int index = static_cast(time_now.seconds()) % 5; // pick random pin return pins[index]; }

Example Subscriber Code: python Copy code

Subscriber node to handle serial communication with Arduino

serial_port.write(f'{pin}\n'.encode())  # Send pin number
response = self.serial_port.read()  # Read Arduino response

Troubleshooting

  • Arduino Not Responding: Ensure the correct port is specified in the ROS2 code (/dev/ttyUSB0). You can check the connected devices with ls /dev/tty*.
  • WSL USB Access: If you're using WSL, remember that WSL does not have access to USB devices by default. Use usbipd to share USB devices between Windows and WSL.

Contributions

Feel free to fork the project and submit pull requests. If you find any bugs or issues, please open an issue in the GitHub repository.

License

This project is licensed under the MIT License - see the LICENSE file for details.

This README should provide clear instructions for setting up and running the project, as well as details on the code and how to troubleshoot any issues.