[Coral] Getting Started with Coral

Through the Ambient AI Bootcamp from Seoul National University Graduate School of Data Science, I was given a chance to experience AI on edge TPU with Google Coral. This post is based on the practice sessions during the Bootcamp.

The Coral Dev Board

Coral is an edge device toolkit provided by Google. The Coral Dev Board is a single-board computer that performs high-speed ML inferencing. It supports Tensorflow Lite models that satisfy certain characteristics.[1]

Figure 1. The Coral Dev Board

The Coral Dev Board has two USB-C ports. The left is the data port and the right is the power port. Use cables to connect the data port to your computer and the power port to the power socket.

Setup(Windows)

Before you begin, you must make sure that Python 3 is installed in your computer. Check the location of your python.exe file. If it is located in folders whose names contain empty space(' ') or other special characters, it might be safer to place a copy of your Python 3 executable file in a location with a simpler address, e.g. /C/Executables.

Open the Git Bash terminal and enter the following commands. Replace /C/Executables/Python37_64 with the location of your python executable file. This code makes it available to run python files with the command python3.

$ echo "alias python='winpty /C/Executables/Python37_64/python.exe'" >> ~/.bash_profile
$ source ~/.bash_profile

Then install the Mendel Development Tool(mdt) with the following code. Replace Executables/Python37_64 with the location of your python executable file.

$ python -m pip install mendel-development-tool
$ echo 'export PATH="$PATH:$HOME/.local/bin"' >> ~/.bash_profile
$ echo 'export PATH="$PATH:$HOME/Executables/Python37_64/Scripts"' >> ~/.bash_profile
$ echo "alias mdt='winpty mdt'" >> ~/.bash_profile
$ source ~/.bash_profile

Now we can connect to our Coral board with mdt. Here are some of the mdt commands that are used often.

mdt devices: looks for Coral boards nearby

mdt shell: connects to Coral board

mdt push <FILE>: pushes file from local computer to Coral board

Keep in mind that the mdt commands are used when not connected to the Coral board. You cannot push a local file to Coral with mdt push when you are already connected to Coral. You must run exit to break the connection before pushing files.

When connecting to Coral for the first time, first run mdt devices. Git bash will show you the name of the board(for example, mine is yellow-valet) connected to the computer via the cable. Then run mdt shell to connect to that device. Now we can connect the board to Wi-Fi to access the board more easily. Use the following command. Replace <NETWORK_NAME> and <PASSWORD> with corresponding values.

nmcli dev wifi connect <NETWORK_NAME> password <PASSWORD> ifname wlan0

After connecting your Coral board to Wi-Fi, mdt shell alone may not locate your device if there are multiple boards connected to the same Wi-Fi. There are two ways to mitigate this problem. First, you may run mdt shell <BOARD_NAME> to connect directly to the desired board. Or you could tell your computer to memorize the name of your Coral board. For this run mdt set preferred-device <BOARD_NAME>. Then mdt shell would always be able to locate your board when connecting.

References

[1] Google, 2020, "Dev Board", Coral, Retrieved 12:05, August 31, 2022 from https://coral.ai/products/dev-board/