The Daily Grind Upgrades a Coffee Grinder with a New User Interface, Using a Raspberry Pi Pico
Designed to make it simple to "dial-in" a coffee grinder, The Daily Grind is an open source MicroPython-powered solution to coffee woes.
Maker collective VEEB has given a Raspberry Pi Pico a very important job indeed, putting in in charge of preparing coffee grounds — selecting just the right grind for a particular brew.
"Moving between grind sizes for different brew methods can be a mild frustration on some coffee grinders. Remembering where the last grind was is not always easy," VEEB's Vanessa Bradley explains of the problem she's been trying to solve. "This is an attempt to smooth out the workflow and an excuse to play with a [Raspberry Pi] Pico microcontroller, which has been on the to-do list for a while."
The Raspberry Pi Pico, running MicroPython, is connected to an OLED display and rotary encoder as a user interface and given the job of running a DC motor — the latter connecting to what was originally an off-the-shelf Bezzera BB005 coffee grinder.
"Different coffee brew methods require coffee that is ground to a different coarseness. Getting it just right is known as 'dialing in', and a dialed-in grind is a beautiful thing," Bradley explains. "Adjusting some grinders from fine espresso grinds to coarse pourover grinds seems to take forever. Invariably, you forget where it was when you started and you've most likely ruined the next cup of espresso you’ll be having."
The Raspberry Pi Pico deals with those issues by offering a more detailed user interface than the stock grinder, displaying the last few grinds automatically — making it easier to find the perfect grind again.
"There is plenty of scope for refinement," Bradley adds. "If a calibration step is built in to avoid 'drift' between grinds, then the code can store all grinds it performs. If it can collect other parameters (via the user interface) then it can start doing smarter things."
More details are available on the VEEB blog, while the source code for what Bradley has called The Daily Grind is available on GitHub under the reciprocal GNU General Public License 3.