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Overview

Introduction¤

The motion controller project FluidNC allows for the expansion of functionality using its channels protocol. In addition to receiving GRBL g-codes and extension commands over a UART channel, FluidNC will provide a stream of data that follows the GRBL Line Protocol and FluidNC's serial protocol. This data can be used to update a display, control other devices, etc. Over a UART channel, FluidNC will also send initialization information that describes how the channel listener (aka expander) should configure itself so that it can receive specific control commands.

FluidPy is a python library that provides an interface for interacting with FluidNC's serial protocol.

Platforms¤

FluidPy is currently supported on Python 3.10+, MicroPython and CircuitPython which enables interfacing with the FluidNC controller on multiple platforms including microcontrollers, single board computers (with a GPIO header such as a RaspberryPi) or even full desktop computers (with a serial to USB adapter).

Wiring diagrams are below for a few example platforms. When defining the uart section in your FluidNC config, note the Tx pin of the controller connects to the Rx pin of the expander microcontroller; and the controller's Rx pin to the expander's Tx pin.

Getting started...¤

Additional details can be found at read the docs.

...with microcontrollers¤

CircuitPython can be run on a wide range of microcontrollers.

  1. Install CircuitPython per the instructions on the CircuitPython website.
  2. Clone this repository and copy the contents of src/fluidpy to the lib/fluidpy directory of your CircuitPython device.
  3. Copy examples/cpy_example/main.py to main.py on your device (delete code.py if it exists).

...with computers¤

  1. Create a new python virtual environment: python -m venv .venv; source .venv/bin/activate
  2. Install the fluidpy library: pip install fluidpy
  3. Copy examples/py_example.py to your project directory as main.py.

Connections¤

Note: Microcontrollers can be powered by the +5V from the UART header or the RJ12 connector, but should not be connected while communicating with the microcontroller via USB.

PiBot v4 board with a Seeeduino Xaio RP2040 microcontroller.
Corgi board with a Raspberry Pi Pico microcontroller.
Raspberry Pi connections.