Run a Custom Ubuntu OS for Mini Pupper

After playing with the Mini Pupper for a while, I noticed there isn’t a straight-forward guide to configuring a Ubuntu ARM desktop image for it. The following should help users set up an Ubuntu Mate installation for use with a Mini Pupper.

Install the OS and Raspberry Pi Dependencies

Get Raspberry Pi image of Ubuntu Mate (20.04), specifically version 20.04/arm64 which can be found here. Make sure to download the ubuntu-mate-20.04.1-desktop-arm64+raspi.img.xz image!

Next, use balenaEtcher to write the image to and SD Card.

NOTE: If you are trying to write this image using Ubuntu 22.04 on your HOST computer, then you will need to run balenaEtcher with a CLI and the following flags since they are using an old version of Chromium according to this GitHub issue: - ./balenaEtcher-1.7.9-x64.AppImage --no-sandbox --disable-gpu-sandbox --disable-seccomp-filter-sandbox

Plug into Raspberry Pi and follow installation instructions.

IMPORTANT: Make sure to make your username ubuntu, if you use any other username none of the QuadrupedRobot libraries will work! You can give any name for the computer name.

After installation, update the OS inside a terminal window.

~$ sudo apt update && sudo apt upgrade -y

Install OpenSSH Server

~$ sudo apt install openssh-server

Open firewall (if needed)

~$ sudo ufw allow 22
~$ sudo ufw reload

Install git

~$ sudo apt install git

Optional Installation of sshguard

~$ sudo apt install sshguard

Install QuadrupedRobot libraries

Create an empty .hw_version file in the home/ubuntu directory.

~$ cd ~/
~$ touch .hw_version

Create a Robotics directory in your home directory and cd into it. - This needs to be done or many of the installation scripts for the Mini Pupper will fail.

~$ mkdir Robotics
~$ cd Robotics

Clone the QuadrupedRobot repository

~$ git clone https://github.com/mangdangroboticsclub/QuadrupedRobot.git

cd into the Legacy directory and install legacy components.

~$ cd QuadrupedRobot/Legacy
~$ bash pre_install.sh

Install MangDang components

~$ cd /home/ubuntu/Robotics/QuadrupedRobot
~$ bash install.sh

Enable PWM access to ubuntu user

This is a modification of the solution here. First, create a /etc/udev/rules.d/99-com.rules suing sudo:

~$ sudo nano /etc/udev/rules.d/99-com.rules

And fill with the following:

SUBSYSTEM=="pwm*", PROGRAM="/bin/sh -c '\
	  	    chown -R root:gpio /sys/class/pwm && chmod -R 770 /sys/class/pwm;\
	  	    chown -R root:gpio /sys/class/pwm/pwmchip0/pwm* && chmod -R 770 /sys/class/pwm/pwmchip0/pwm*;\
	  	    chown -R root:gpio /sys/devices/platform/soc/*.pwm/pwm/pwmchip* && chmod -R 770 /sys/devices/platform/soc/*.pwm/pwm/pwmchip*\
'"

Save, reload rules, and then reboot:

~$ sudo udevadm control --reload-rules
~$ sudo udevadm trigger
~$ sudo reboot

This will enable the Pupper to use PWM without needing root access since we are now giving the group gpio access to PWM.

Finally, when your system restarts you’ll notice that your Mini Pupper’s eyes will light up greeting you with a successful installation!