Here are my design files for KiCad PC board design, FreeCad mechanical design, and MPLAB-X code development.  Feel free to use and share them for your own purposes.

MIDI-Lappi Eurorack Sound Module

Design Files

This module interfaces the lovely Adafruit VS1053 assembly to eurorack and MIDI signals.  The VS1053 chip provides the General MIDI sound set.

PDF schematic for MIDI-LAPPI module:


KiCad PC board file for MIDI-Lappi module electronic board:


KiCad PC board file for MIDI-Lappi faceplate board:


Parts List:

This is my Digi-Key bill of materials for the MIDI-Lappi module. It doesn’t include the Adafruit VS1053 codec board, the two custom PC boards, nor the knobs. There is a mix of thru-hole and surface-mount parts.



Ctrl-Surf Eurorack MIDI Generator Module

Design Files

PDF schematic for Ctrl-Surf module electronic board:


KiCad PC board file for Ctrl-Surf electronics board:


KiCad  schematic file for Ctrl- Surf electronics board:

KiCad PC board file for Ctrl-Surf faceplate board:


Parts List:

This is my Digi-Key bill of materials for the Ctrl-Surf module. It doesn’t include the joystick nor the Microchip PC18F26K22 chip, nor the knobs. All of the parts are thru-hole.  There are no surface mount parts on this module.




Mechanical Design Files

This FreeCAD file has both modules.  Ultimately I ended up using this 3D model for visualization and generation of the board spacer/wire guide bracket on the MIDI-Lappi, and the translucent, illuminated push button keycaps for the Ctrl-Surf.

I’m retired now, but this kind of stuff provided a good living for over 35 years, and I still enjoy using and sharing  the techniques I picked up along the way. It’s too hard to quit cold turkey haha.

Back view screen grab from within FreeCAD:

Front view screen grab from within FreeCAD:


MIDI-Lappi bracket 3d printable .stl file:


Ctrl-Surf key caps 3d printable .stl files:

Notice that the four white Preset caps have slightly different dimensions compared to the twelve chromatic yellow (and blue) keyboard key caps.  I printed them all with the same clear translucent filament.  The individual key caps are dropped into the Ctrl-Surf faceplate from behind.  Then, the Ctrl-Surf electronics board is mated to the back of the faceplate, sandwiching the key caps between the switches and the faceplate.