Second attempt to build a zynthian box was successful


a few years ago I wasn’t happy with the sound of my old synthesizer (SY-22) and I thought it would be cool to have a small device with “better” sounds that I could plug in and use the synthesizer mainly as a midi keyboard. With a bit of googling I found the Zynthian project and was pretty impressed. Of course, it can do a lot more than what I originally wanted, but I wanted to try it out. To cut this part of the story short, it kind of worked, but I had trouble putting everything into a case and it wasn’t in a very usable state (I mean my attempt).
But now, a couple weeks ago, I wanted to try again. In the meantime, the V5 had been released, and after reading a bit on the forums, I decided to build my own version inspired by the Mini V2, but without the PCB.

I saw my second attempt as a good opportunity to learn some new things:

  • CAD to design my own 3D models (previously I had only printed things that someone else had designed)
  • Basic electronics
  • Soldering

And now it’s almost finished. Only the hardware MIDI connections are missing. But I wanted to show it anyway.

I used a case from an old IPC, flipped it over and replaced the bottom with the newly designed cover. I use:

  • Raspberry Pi 4b
  • Hifiberry DAC+ADC
  • 2xMCP23017 with 4 encoders and 20 switches
  • Waveshare 5" DSI display with capacitive touchscreen

The switches are connected to the MCPs like it is done in the V5. In stable everything is working fine. In oram I have trouble with the touchscreen. It is rotated by 180°. I tried the instructions from the waveshare page and added the CalibrationMatrix to the /etc/X11/xorg.conf.d/40-libinput.conf:

Section "InputClass"
        Identifier "libinput touchscreen catchall"
        MatchIsTouchscreen "on"
        MatchDevicePath "/dev/input/event*"
        Option "CalibrationMatrix" "-1 0 1 0 -1 1 0 0 1"
        Driver "libinput"

and I can see in the /var/log/Xorg.0.log that the section is read but it doesn’t change anything. When I change the Wiring from “V5” to “Mini V2” the touchscreen is working correctly. Unfortunately then the encoders are inverted and I have to change the actual wiring (switch a/b on the encoders).

Here are some pictures:



Hey @Nils, congrats. Once case is closed it looks very nice. Cause, when opened, like most of diy Zynthian boxes, mine included, it’s a big mess of spaghettis cables.

Don’t forget to share some noise and maybe you can copy paste your above’s message in “success cases” thread.