Arduino Coffee Machine

This project is a PID controller for a Gaggia Paros (or Gaggia Classic) coffee machine using Arduino and a few other components. This Arduino based controller improves the stability of the water temperature of the coffee machine by controlling the boiler with a PID control loop feedback.

Software

This project is based on lib_coffee_machine which is a C++ library providing an abstraction of a generic coffee machine.

This project implements the library interfaces targeting an Arduino Nano platform and several sensors and displays.

Arduino libraries

This project depends on the following Arduino libraries:

Makefile

The Makefile at the project root directory provides targets to build the code and the documentation.

Build

You can build the code with different approaches:

with the Arduino IDE opening the CoffeeMachine.ino sketch
with VSCode and the Arduino extension opening the CoffeeMachine.ino sketch
with make build using Docker

Build with Docker

The code can be built inside a Docker container using docker-compose. The docker-compose.yml and the Dockerfile are in the docker directory. The docker-compose.yml depends on 2 environment variables that must be defined before starting the build:

CORE: the Arduino core
BOARD: the Arduino board to use

Refer to the arduino-cli documentation for the list of available cores and boards. The following is an example that builds the code for an Arduino Nano board:

$ cd /path/to/repo
$ CORE=avr BOARD=nano make build

The generated build files will be in the CoffeeMachine/build directory.

After building the Docker image the first time, you can then use the arduino-cli installed in the Docker image directly with:

$ cd /path/to/repo
$ docker run --rm -it -v $PWD:/build arduino-builder arduino-cli version
arduino-cli Version: 0.10.0 Commit: ec5c3ed

Hardware

Components

This is the list of components I used for the project:

1x Arduino Nano (any board type will do)
1x Solid State Relay 40A
2x Digital temperature sensors (e.g. TSic306)
1x I2C 128x64 OLED
Wires and other supplies

Documentation

Read the project documentation at: https://arduinocoffeemachine.readthedocs.io

Or build it locally with:

$ cd /path/to/repo
$ make docs

Tools

The tools directory contains a Python script that can be used to read the Arduino Serial messages and to plot the current water temperature on a graph. The goal is to help the PID tuning process showing the realtime results.

$ cd tools
$ poetry install --no-dev
$ poetry run python temp_plotter.py

Acknowledgement

A big thanks goes to these two other projects that helped me a lot in the understanding of the electric schematics of the coffee machine and the components to use:

ilcardella/ArduinoCoffeeMachine