ROS 2 Dockerfiles for Raspberry Pi and Turtlebot3

1. Creates a 64-bit bootable disk image and corresponding docker cross-compiling environment for the Raspberry Pi.
2. Takes a minimal and layered approach: various intermediate steps can be used and customized.
3. The primary example is a disk image suitable for use on the Turtlebot3 and a docker environment that enables cross-compilation.
4. It includes slightly-modified Turtlebot3 OpenCR firmware that enables low-level access to the motors and encoders from ROS
5. In the latest example ROS 2 Iron and Ubuntu 22.04 is used.

Cross-compiling

1. Install docker: sudo apt install docker.io
   • This step is done once per computer
2. In the base of a ROS workspace you wish to cross compile run ~docker run reem17/rosberrypi-xcompile:iron > aarch64 && chmod 755 aarch64
   • This step is done once per workspace
3. Compile your code with ./aarch64 colcon_aarch64
   • This step is done whenever you wish to cross compile
   • It invokes colcon build (plus any additional arguments you provide) inside the cross compiling environment
   • The resulting install space is aarch64_install and can be transferred to the remote platform to be used

Setup

0. These steps are for if you want to build or customize the Raspberrypi disk image or the cross compiling docker container.
   • Most MSR students do not need to perform these steps!
1. Install docker and qemu-user-static-binfmt
   • Ubuntu: apt install qemu-user-static binfmt-support docker.io
   • Arch Linux: pacman -S qemu-user-static-binfmt docker
2. Build the rosberrypi docker containers ./build_docker_images.sh [<target>]
   • <target> (optional): which base docker image to create
     • rosberrypi-turtlebot3 (default) A Full turtlebot3 environment with custom NU-MSR firmware available
     • rosberrypi-ros A Full ROS 2 installation.
     • rosberrypi-base A minimal Ubuntu image from debootstrap.
3. Images can be built on top of the rosberrypi-turtlebot3.
   • numsr_image.sh will build a custom (example) image rosberrypi-numsr that sets up an msr user and connects to a wifi network

Writing an Image

1. ./create_disk_image.sh <docker_img> <file>
   • Creates a bootable raspberry pi disk image from <docker_img> and writes it to <file>
   • This works with any compatible docker image. Compatible images can be built by extending one of the built-in images
2. ./write_sd <disk_file> <sdcard> <hostname>
   • Writes the <disk_file> (the disk iamge) to the sdcard at <sdcard>.
   • The <hostname> will be the hostname of the machine
   • The system partition will be expanded to fit the whole card

OpenCR firmware

1. The opencr firmware is built in the opencr/ docker container
2. On the turtlebot, with the OpenCR board plugged in, running opencr_install_firmware will install the firmware on the OpenCR board