This is a stripped down version of the project by TEC.IST that can be found here: https://hackaday.io/project/178204-the-smallest-keyboard
If you have any contributions to make, think you can make this tidier or prettier or cooler, I'm all ears. Make a pull request or raise an issue or feature request or whatever githubbers do. I have a to do list at the bottom of the readme of some ideas I've had to expand the functionality. Most are way above my level, but something that I will likely pick up as I get better.
I found a matrix keypad in an old bit of telecommunication hardware that had a really nice click to the button push. I took it out of the equipment and it sat on my desk for about a month while I played around with it. Eventually I decided that I had to do something with it, to make it useful again so I looked out for a way to turn it into a macropad that I could control Lightburn and my laser engraver.
The only code I could find was for either a matrix keypad or a macro keypad that wired each button to a different IO on an arduino or pi pico.
Finally I found The Smallest Keyboard which does both. Of course there were way more keys than I need, so I stripped it down for my purposes, and as I wanted to use Ctrl and Alt keyboard shortcuts, I added a long and ugly if statement to do that.
For this project I used a Raspberry Pi Pico and a 4x4 matrix keypad that I found. You can however use any matrix keypad or make your own. I modified an STL file for a keypad to fit mine in.
The code requires that Circuit Python be installed on the Pi Pico - Just copy the U2F file to the Pico. You will also need the Adafruit HID keyboard and keycode libraries - Download the library that matches your version of Circuit Python and copy the files at /lib/adafruit_hid/ to the /lib folder on the Pico.
To program this, you can quite simply drag and drop the code.py file to the pico, or to test, you can use thonny and select the pico as the interpreter. I found a tutorial here but a quick Searx will give you instructions on setting this up.
The matrix keypad was old and the pins weren't in the order that I though they were. I managed to find the pinout online
- Implement a bank key and add some banks for switching between different tasks. eg. bank 1 controls OBS, bank 2 controls Photoshop
- Add LEDs 'cause everything needs bright lights
- Add an LCD to show a layout of what each key does - especially useful if you're banking
- change from macropad to midi controller?
- See if this will work with F keys 13 through 24
- some way to dynamically assign shortcuts/macros
- give it tentacles (ok, that one was a joke, but actually everything is better with tentacles)