Moving between grind sizes for different brew methods can be a mild frustration on some coffee grinders. This modification lets you do it with a single click. Also, remembering the location of the previous grind is not always easy. This leads to wasted coffee..... unacceptable.
An open-source coffee grinder accessory to aid moving between grind sizes, and recalling recent grinds. Prototyped on a Bezzera BB05, although it should be adaptable to other grinders that use a similar mechanism (stepless adjustment). The numbers are currently non-dimensional (no units/made up).
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A minimal user interface centers around a numeric value for the grind size and a display of that numeric value for the last 3 grinds.
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Turn the rotary encoder to select a grind number, after a short pause, the grinder adjusts.
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Go to the previous grind setting (handy for switching between brew methods) - short-press of rotary encoder.
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Tare function - long press the rotary encoder to zero the counter at a grind size (there is a visual setpoint on the grinder to do this at present).
- Screen: SSD1351 OLED 128x128 screen
- Motor Driver: Waveshare DC motor board for Pico (jumpers soldered for I2C 1 to avoid screen issues due to pin use)
- Motor: DC motor
- Controller: Rotaty Encoder switch
- Timing belt and teeth
- Wires galore
- 12V DC power for the motor
- The mechanics of attaching the motor to the adjustment knob is an exercise for the reader
The list of connection pins for all of the parts interfacing with the Pico are within the main.py, there are also tables below.
Once you've installed Micropython on the Pico. Clone this repsitory onto your computer:
git clone https://github.com/veebch/thedailygrind
and copy the files onto the Pico (connected to your computer via USB):
sudo ampy -p /dev/ttyACM0 put ./
- Plug the Pico into the Waveshare motor driver board
- Connect the DC motor to A1 and A2 on the driver board
- Connect 12V DC power to the waveshare driver board (marked 6-12V and GND)
- The OLED connects to the GPIO as follows:
| Pico GPIO | OLED |
|---|---|
| 19 | DIN/MOSI |
| 18 | CLK/SCK |
| 17 | CS |
| 20 | DC |
| 21 | RST |
- The Rotary Encoder connects to the GPIO pins as follows:
| Pico GPIO | Rotary Encoder |
|---|---|
| 2 | CLK |
| 3 | DT |
| 4 | SW |
The code is saved as main.py, so it will automatically run when you power up the Pico.
- Auto-calibration, perhaps using a precision limit switch
- Collect additional information via UI
- Stretch goal: Build a grinder from scratch
This code works, but is a first draft. If you look at this, find it interesting, and know you can make it better then please fork the repository and use a feature branch. Pull requests are welcome and encouraged.
If you have some coffee expertise that you think could be embedded in the code then raise an issue on GitHub or mail us.
GPL 3.0