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Set Raspberry Pi 4B as an onboard computer

Big picture of a drone with a Pixhawk 5 and a Raspberry Pi 4b.

Albuquerque, New Mexico

1. Brief introduction of onboard computer (Raspberry Pi 4B)

Onboard computer is responsible for transfer commands from base station to autoploit and convert sensor information from autoploit, cameras etc. back to Onboard computers.

Choices for onboard computers are Raspberry Pi, Odroid, Tegra K1 etc. Here we show how to buid a drone using Raspberry Pi, i.e. Raspberry Pi 4B.

Albuquerque, New Mexico

Raspberry Pi 4B

Raspberry Pi requires an operating system (OS). However, The supported OSs by Raspberry Pi depend on versions. Raspberry Pi 4B can only support Ubuntu desktop 21.04 (Not LTS), Raspberry Pi OS, Ubuntu server 20.04 (LTS), Ubuntu Core 20, which can be found at (see Ubuntu for Raspberry Pi).

2. Tools for installing operating systems on Raspberry Pi 4B

Note: An image is provided for team members that is Ubuntu Mate for Raspberry Pi 20.04 with ROS and mavors. Raspberry Pi Imager is official tool to install OS for raspberry pi boards. It can be downloaded from https://www.raspberrypi.com/software/.

A Youtube video is available here.

Raspberry Pi Imager

Here are several potions for OS to be used on Raspberry Pi 4b:

  • Ubuntu Desktop/Server 20.04
  • (recommended) Ubuntu Mate 20.04 for Raspberry Pi
  • Raspberry Pi OS

3. Install Ubuntu Server 20.04

A server is lighter than a Desktop as it does not contain packages for GUI and Office. Thus, choosing server is also a good choice for an onboard computer.

  1. Choose Ubuntu Server 20.04 LTS using Raspberry Pi Imager.
  2. Insert the SD carder in Raspberry Pi and start it with a mouse, keyboard and a monitor connected.
  3. Log in Ubuntu server with
    • username ubuntu
    • password ubuntu
  4. Connect Raspberry Pi to Wifi using netplan explained here
    • check Internet class ls /sys/class/net
    • find and edit config file sudo nano /etc/netplan/50-cloud-init.yaml
    • put available wifi infor as
        wifis:
        wlan0:
            dhcp4: true
            optional: true
            access-points:
                "WIFI_ID":
                    password: "WiFi_password"
    • apply this config sudo netplan generate
    • connect to Wifi sudo netplan apply
  5. reboot
  6. Install Mate Desktop environment
    • sudo apt install taskel
    • sudo apt install ubuntu-mate-desktop
    • choose gmd3 or lightdm (recommended)

4. Install Ubuntu Mate (for Raspberry Pi) 20.04 from Ubuntu Server 20.04

Repeat Steps 1-5 above in Step 2A.

  1. Use Desktopify to convert Ubuntu server 20.04 to Ubuntu Mate 20.04. A video tutorial is available Install Ubuntu Mate On the Raspberry Pi 4 with Desktopify The Fastest Desktop Experience For The Pi4.
    • cd ~ git clone https://github.com/wimpysworld/desktopify.git
    • cd desktopify sudo ./desktopify --de ubuntu-mate
      Take the sd card and put it into the sd slot.

Connect the Raspberry Pi with a monitor through a HDMI cable, a mouse through a USB port, a keyboard through a USB port. Then, use the power supply module provided by the manufacturer.

Now, we should see a Ubuntu Mate start in the monitor. Here is what we need to do for configure basics of the OS.

  1. Boot your Ubuntu MATE
    • set language and user names
      • user name: droneREEG
      • passwork: 123456
      • computer name: drone1 (drone2 for a second drone)
      • this can also be done by specifying options of Raspberry Pi Imager before installing
  2. Disable auto update in Software&Updates > Updates
    • stop ubuntu kernel update 
          sudo apt-mark hold linux-generic linux-image-generic linux-headers-generic

5 Install Raspberry Pi OS (not fully tested)

Raspberry Pi OS is an official operating system supported by Raspberry Pi.

After understanding how to use Raspberry Pi Imager, a choice is going to be made for choosing a version of Raspberry Pi OS, yes, another choice of versions :( . In fact, Raspberry Pi OS is built using a Linux kernel of Debian, therefore we can find Debian version information of each Raspberry Pi OS. Raspberry Pi OS uses Debian 11 (Bullseye), while Raspberry Pi OS (Legacy) takes Debian 10 (Buster).

Raspberry Pi OS with Debian 11 (Bullseye)

Raspberry Pi OS (Legacy) with Debian 10 (Buster)

Wait a minute. Think about the most important tools are to be used on onboard computers; that is ROS. Choosing Raspberry Pi OS (Debian 11) or Raspberry Pi OS (Legacy) (Debian 10) depends on which one allows us to use a proper ROS.

Till April 2022, there two ROS options to choose: ROS Melodic and ROS Noetic. Noetic is developed for Debian 10 (Buster) and Melodic is for Debian 9 (Stretch). So, Debian 11 (Bullseye) is not supported yet for ROS 1 or never. The only choice is Debian 10 (Buster), then we must install Raspberry Pi OS (Legacy).

Flashing Raspberry Pi OS (Legacy) into a SD card and use that to boot Raspberry Pi.

6 Install Ubuntu Core for Raspberry Pi

6.1 Introduction of Ubuntu Core

In one word, Ubuntu Core is the optimised version of Ubuntu for robotics and ROS. Snaps, the de facto container for packaging software on Ubuntu, enhanced to support ROS applications.

Ubuntu official site states that

  • Ubuntu Core is a version of the Ubuntu operating system designed and engineered for Internt of Things (IoT) and embedded systems.
  • Ubuntu Core is ideal for embedded devices because it manages itself. Whether it’s running on an Intel NUC hidden for media streaming, or a Raspberry Pi handling garage door automation, Ubuntu Core remains transparent, trustworthy and autonomous.

More information about how Ubuntu supports robotics can be found at

6.2 Tutorial for using ROS on Ubuntu Core

https://ubuntu.com/core/docs/uc20/install-raspberry-pi#heading--requirements

Ref: