ubuntu-install.md

Installation and Configuration of Ubuntu and ROS on RasPi4

• Install Ubuntu MATE 20.04 LTS on Raspberry Pi 4

  • (On Windows) Write file ubuntu-mate-20.04.1-desktop-arm64*raspi.img.xz to 32 GB micro SDcard using Raspberry Pi Imager
    • This takes about 30 minutes
  • Boot Pi from new SDcard and configure
    • This takes about 10 minutes
  • Unattended update
    • This takes about 3 hours
  • From Welcome screen -> Getting Started -> System Specifications -> Utilities
    • Install:
      • System Profiler and Benchmark
      • GParted
      • Psensor

• sudo apt update

• sudo apt upgrade

• At this point, with about 4.5 hours invested, I thought it might be a good idea to make a backup image of the micro SD card

  • Used Win 32 Disk Imager on Windows
    • This took about an hour

• Add 'GitLab Markdown Viewer' extension to Firefox

  • None of the markdown viewer extensions worked.
  • Solution: Create a new mime type and update mime database
    • How to get the Markdown Viewer addon of Firefox to work on Linux

• Alternatively, use Markdown Viewer Webext addon to Firefox

• Resolve /usr/bin/env: ‘python’: No such file or directory errors running python programs starting with !#/usr/bin/env python

  • Added symbolic link. sudo ln -s python3 /usr/bin/python

• Add robot (and raspi80) to /etc/hosts

• Install ROS: Ubuntu install of ROS Noetic

• Configure ROS Environment: Configuring Your ROS Environment

• Add line to ~/.bashrc : source ~/catkin_ws/devel/setup.bash

• Install Arduino IDE and rosserial. (It turns out, this isn't used. I thought I was going to need it, but then I discovered PIGPIO.)

• Configure passwordless ssh to robot How to setup SSH login without password on Linux systems

• Load codec to enable watching youtube videos. sudo apt install libavcodec-extra

• Still trying to get video and sound working. Need to edit a couple of files.

  • Google search took me here which has a link here

• Install pip

  • sudo apt update
  • sudo apt upgrade
  • sudo apt install python3-pip

• pip install RPi.GPIO

• Install idle sudo apt install idle3

• Install python mathutils library pip install mathutils (Has a handy utility function used to normalize quaternion.)

• Install Jupyter Notebook: How to Install Jupyter Notebook on Ubuntu 20.04 / 18.04. (This isn't actually needed. I installed this when I was trying to learn more about why I couldn't get robot-pose-ekf node working.)

  • Create ~/notebook/ directory (in home dir)
  • Cloned Kalman-and-Bayesian-Filters-in-Python under ~/notebook
  • Cloned Think Autonomous Stereo Vision Course under ~/notebook
  • To enter jupyter virtual env: source notebook/jupyterenv/bin/activate
  • Within jupyterenv, pip install the following:
    • scipy
    • numpy
    • matplotlib
    • filterpy
    • sympy
    • opencv-python
  • To start: jupyter notebook

• Install Caja Share (samba) allowing files on robot to be opened in Caja (This is pretty handy. It allows editing files on robot from raspi4.)

• Install git -> git version 2.25.1 already installed!

  • git config --global user.email "dblanding@gmail.com"
  • git config --global user.name "dblanding"
  • Generating a new SSH key and adding it to the ssh-agent
  • Adding a new SSH key to your GitHub account

• Install teleop_twist_keyboard sudo apt install ros-noetic-teleop-twist-keyboard

• Install gmapping and navigation (This isn't needed either. It turns out all the navigation is being done on robot.)

  • sudo apt install ros-noetic-gmapping
  • sudo apt install ros-noetic-navigation

Here is some hard won Ubuntu-Mate knowledge that I wouldn't want to have to learn a second time...

One day, for no obvious reason, the raspi4 wouldn't connect to wifi. The timing of this issue coincided with a service interruption, so I immediately jumped to an incorrect conclusion. I would be embarassed to say how long I struggled before I figured out the cause. Eventually, I realized what was going on. Months ago, I had fiddled with Mate Tweak to have a look at some alternative desktop styles. In the process, the panels and desktop layout had changed and I didn't notice that the wifi-network-manager applet was no longer displayed in the top panel, nor did I even wonder why it was missing. Once I realized that my desktop was missing its network manager applet from the control panel, it was very simple to restore it:

• From the Control Center, click MATE Tweak
  • Select Panel then switch to "Traditional"
  • Et voila! The wifi manager applet symbol shows up in the top panel.
  • Clicking on it displays a drop down dialog with, among other things, an item labeled Enable WIFI. I clicked it on and the WIFI connected immediately.