Code for the onboard arduino. Allows the arduino to talk to the computer by serial using a set of utf-8 string messages. You can read these messages on the computer using the arduino ide's serial monitor tool, or programmatically, using eg. the python serial library.
We also have code for broadcasting these serial messages over a websockets connection (see websockets-serial), allowing for a browser-based user interface and (conceivably, in the far future) authenticated network access to the command and telemetry interfaces.