Introduction

Installing ROS on a Raspberry Pi 4 is difficult because, though the ubuntu images seem good to go, I experienced unknown problems setting up a headless install of ubuntu 18. Ubuntu 20.04 worked eventually, but initial startup took over 5 minutes for the device to show up on my network. Plus I was interested in installing ros melodic, which is built for ubuntu 18. So here are the steps I used. I installed raspbian buster and compiled ros from scratch.

Instructions

1. Download the Raspberry Pi Imager: https://www.raspberrypi.org/downloads/

   Alternate imagers:

   • win32diskimager
   • https://www.balena.io/etcher/

2. Download an Image: I used the lite version and then added packages as needed

   • https://www.raspberrypi.org/downloads/raspbian/

3. Install raspbian using the instructions for a headless install located here: https://www.raspberrypi.com/documentation/computers/configuration.html#setting-up-a-headless-raspberry-pi

   Alternate instructions:

   • https://hackernoon.com/raspberry-pi-headless-install-462ccabd75d0

4. Make sure you follow the instructions below for setting up wireless & ssh

   Other information:

   • International codes: https://en.wikipedia.org/wiki/ISO_3166-1
   • General: http://wiki.ros.org/ROSberryPi/Installing%20ROS%20Melodic%20on%20the%20Raspberry%20Pi

5. Find the Pi on your network (in linux). You can use a virtual machine to do this

   sudo apt install -y net-tools nmap
   arp -na
   nmap -sn 10.0.0.*
   

   Note the IP address

6. log on using putty

7. Define a static IP address (derived from here)

   1. edit dhcpcd.conf

      sudo nano /etc/dhcpcd.conf
      

   2. uncomment out lines for static ip/subnet and router and define them to what you need.

   3. Restart

      sudo reboot
      

   Alternate Instructions(I didn’t use):

   • https://thepihut.com/blogs/raspberry-pi-tutorials/tutorial-how-to-give-your-raspberry-pi-a-static-ip-address
   • https://www.raspberrypi.org/forums/viewtopic.php?t=133691

8. install xrdp (using this tutorial):

9. install gedit

   sudo apt install gedit
   

10. Install ROS using this tutorial

    Alternate Instructions(didn’t use):

    • https://www.seeedstudio.com/blog/2019/08/01/installing-ros-melodic-on-raspberry-pi-4-and-rplidar-a1m8/

11. change password for user pi

    passwd
    

12. Set up camera using this tutorial

Note: This section may be outdated. Please see this section about libcamera

1. install other packages for viewing and programming

    ```
    sudo apt install gpicview vlc thonny
    pip3 install picamera
    ```

1. After installing picamera there may be a warning.  use the next lines to fix:

    ```
    echo "export PATH=\$PATH:/home/pi/.local/bin" >> ~/.bashrc
    source ~/.bashrc
    ```

1. install opencv using this tutorial

   Notes:

   • I used option 4a
   • I didn’t use virtualenv…space reasons.
   • use sudo pip3 install instead of pip install to install in python3

2. install other necessary packages

   sudo apt install -y libilmbase-dev libopenexr-dev libgstreamer1.0-dev
   

3. clone raspicam node

   git clone https://github.com/idealabasu/raspicam_node.git
   

4. not sure these packages are needed:

   sudo apt install python3-catkin-pkg
   sudo apt install python3-rosdep python3-rosinstall python3-rosinstall-generator python3-wstool build-essential
   sudo apt-get install python3-empy
   

5. update ros install with joystick and compressed image transport packages, following instructions here:

   and using

   rosinstall_generator ros_comm joystick_drivers compressed_image_transport camera_info_manager dynamic_reconfigure diagnostic_updater cv_bridge --rosdistro melodic --deps --wet-only --tar > melodic-custom_ros.rosinstall
   

6. Add idealab ros workspace: (see other tutorial)

7. checkout rpi4 branch

   git checkout rpi4
   

8. (Mental Note) cloned and copied raspicam_node into code_idealab_ros/src (don’t do, already done)

   1. Make projects

      cd ~/code/code_idealab_ros
      catkin_make
      

9. optional: change ros master uri to remote. Only necessary if you want the raspberry pi to work within a bigger ros network. Modify ip addresses to match desired network topology

   echo "export MY_MASTER_IP=10.0.0.201" >> .bashrc
   echo "export MY_IP=10.0.0.200" >> .bashrc
   echo "export ROS_MASTER_URI=http://\$MY_MASTER_IP:11311" >> .bashrc
   echo "export ROS_IP=\$MY_IP" >> .bashrc
   source .bashrc
   

10. Run Roslaunchp (modified from here

    #roslaunch raspicam_node camerav2_1280x720.launch
    #roslaunch raspicam_node camerav2_410x308_30fps.launch
    roslaunch raspicam_node dan_cam1.launch
    

11. on the host:

    1. in one terminal:

       roscore
       

    2. in a second terminal:

       rosrun rqt_image_view rqt_image_view