I made a custom 3-key macropad for media control. The keyboard has three buttons: previous track, next track, and play/pause. I designed the PCB in KiCad, modeled the case and top plate in Autodesk Fusion 360, and wrote the firmware using KMK with CircuitPython.
The most challenging part was designing the 3D case around the PCB, especially aligning the USB-C cutout, adjusting the wall height, and making the top and bottom pieces fit correctly. I also had to learn how to export the PCB as a STEP file and use it as a reference inside Fusion 360.
I am proud that I built the whole project from the electronics to the mechanical case and firmware. This was my first time using Fusion 360, so finishing a working enclosure with a top plate, bottom case, USB cutout, and screw mounting points was a big achievement.
To test the project, flash CircuitPython onto a compatible board such as the Seeed Studio XIAO RP2040, copy KMK to the CIRCUITPY drive, and place the `code.py` firmware file on the board. The switches are connected to pins D0, D1, and D2, and the LEDs are connected to D3. Once connected to a computer, the macropad should work as a USB keyboard and send media control commands.
