ROS 2 Raspberry Pi GPIO Control Package

ROS 2 package to control Raspberry Pi GPIO pins

This packages allows you set and read Raspberry Pi GPIO pins via ROS 2 action calls.

Tested with Raspberry Pi3, ROS2 Eloquent, and Ubuntu 18.04 Server

Link to the project video: https://www.linkedin.com/embed/feed/update/urn:li:ugcPost:6654600397346484224

Demo:

1. Build Instructions

source /opt/ros/<ros2_distro>/setup.bash
mkdir <your_ros2_ws_name>
cd your_ros2_ws_name
mkdir src
cd src
git clone https://github.com/mlherd/ros2_pi_gpio.git
cd ..
colcon build --sysmlink-install
source install/setup.bash

2. Usage

• 2.1 Setup Raspberry Pi

  • Download Ubuntu Server 64-bit
    • https://ubuntu.com/download/raspberry-pi
  • Flash the image file on your MicroSD card. I use Etcher on Ubuntu and Rufus on Windows.
    • Etcher: https://www.balena.io/etcher/
    • Rufus: https://rufus.ie/
  • Default user name is ubuntu and password is ubuntu.
  • Set up WiFi connection. You can skip this step if you want use the eternet port.

    • sudo nano /etc/netplan/50-cloud-init.yaml

    •  network:
           ethernets:
               eth0:
                   dhcp4: true
                   optional: true
           version: 2
           wifis:
               wlan0:
                   optional: true
                   dhcp4: true
                   access-points:
                       "<Your WiFi Name>":
                           password: "<Your WiFi Password>"
      

      • Save the file and apply the changes
        • sudo netplan --debug try
        • sudo netplan --debug generate
        • sudo netplan --debug apply

    • Generate SSH Keys

      • sudo ssh-keygen -A

    • Install ROS 2 Eloquent

      • https://index.ros.org/doc/ros2/Installation/Eloquent/Linux-Install-Debians/
      • Make sure you install ROS-Base Install (Bare Bones)

    • Install development tools and ROS tools

      • https://index.ros.org/doc/ros2/Installation/Eloquent/Linux-Development-Setup/

• 2.3 Edit gpio_pins.txt

  • <pin_id>,<input_output>
  • example:
    • 17,out
    • 18,in

• 2.4 Run pi_gpio_server

  • You may need to have super user permissions to access GPIO pins
  • sudo su
  • ros2 run pi_gpio pi_gpio_server

• 2.5 Send goals to the action server

  • example via command line interface:
    • ros2 action send_goal <action_name> <action_message_type> <action_goal>
    • ros2 action send_goal pi_gpio_server pi_gpio_interface/action/GPIO {'gpio: "17,high"'}
    • ros2 action send_goal pi_gpio_server pi_gpio_interface/action/GPIO {'gpio: "18,low"'}
    • ros2 action send_goal pi_gpio_server pi_gpio_interface/action/GPIO {'gpio: "18,read"'}

3. Nodes

• 3.1 /pi_gpio_server

  • ROS 2 action server node

  • 3.1.1 Actions

    • Action name: pi_gpio
    • Action type: pi_gpio_interface/action/GPIO
    • pi_gpio (pi_gpio_interface/action/GPIO)
      • Goal
        • string gpio
      • Result
        • int32 value
      • Feedback
        • int32 feedback