ROS2 for Raspberry Pi Zero W

These are my personal notes for installing the Robotic Operating System 2 Bouncy Release into Arch Linux ARM OS running on a Raspberry Pi Zero W. I had help from @pokitoz and @WilliamLNelson, and the ROS2 for Arm instructions.

Instead of the aarch64 crosscompiler I used crosstool-ng to generate a cross-compiler for my hardware. Specifically I modified the armv6-rpi-linux-gnueabi toolchain to be 1) static and 2) not build and install locales. I encountered this issue and applied the fix. Once the cross-compiler was built I modified the ROS2-for-arm cmake file to use it.

Host Setup

I used an Ubuntu 18.04 virtual machine as the host to build ROS2 on. Using the procedure of configure-host.sh, I configured my host as a build machine for ROS2 Bouncy.

ROS2 Build

Once my host was setup, I built the ROS2 codebase using the crosscompile toolchain. My procedure is documented in the configure-ros2.sh script.

Arch Image

Then I built the Arch Linux ARM Operating System for the Raspberry Pi by setting up an image to flash to an SD card. I used the configure-host.sh script passing it two arguments: 1) an argument for image size; and 2) an argument to the ROS2 install directory. $./configure-image.sh 8G /path/to/ros2/install

Setup Using Chroot

Next I mounted the image that was created into chroot jail. This allowed me to configure SSH and WiFi for headless login on first boot. I access chroot by $sudo chroot /mnt /usr/bin/bash and use the qemu emulator. The Arch Image configuration already copies the configuration script to the chroot /tmp folder. It accepts the SSID and Password of a WPA WiFi device as arguments.

cd /tmp
./configure-chroot.sh SSID PASSWORD
# setup the ROS2
cd /opt/ros2
source setup.bash

Teardown

Once the chroot is exited the teardown script should be executed to umount the image and detach the loop device. The loop device used is saved in loopdevice.txt. $sudo ./teardown /dev/loopX

First Login

Write the image to a micro SD card and then insert the card into the Pi. It should auto-connect to the wifi and you can ssh to it using its IP address given by DHCP on the router. The username is "pi" the password is "secret".

ISSUES

2018-08-30 - rclpy is not importing module paths correctly

pokitoz/ros2-raspberry-pi-zero-w