Since the first one, I've made some changes to the design, and built a new one on this. With my son we also worked on a mobile app to drive it from bluetooth, and we even added a Raspberry PI (3b+) to handle reading midi file and implement a accompaniment mode and learn mode.

I'll publish information about these changes during the coming weeks.

Next week will be hardware stuff.

Basically replacement of arduino with mega 2560 (to use 2 hardware serials) and adding level shifter between arduino and mpr121.

You can see first tests here :

https://www.youtube.com/watch?v=QrhrvHwBTaA

https://www.youtube.com/watch?v=lHdwECdyA4Q

And a google album here :

https://photos.app.goo.gl/bQ4mV23pNtbU5JTR7