https://www.youtube.com/watch?v=4QYlIZP8Dl4

https://oshwlab.com/scherbakov.al/controller2

https://oshwlab.com/scherbakov.al/1-a0-c3-on

https://oshwlab.com/scherbakov.al/2-c_3-g_4-on

https://oshwlab.com/scherbakov.al/3-a4-f6-on

https://oshwlab.com/scherbakov.al/4-f_6-c8-on

https://oshwlab.com/scherbakov.al/1-a0-c3-off

https://oshwlab.com/scherbakov.al/2-c_3-g_4-off

https://oshwlab.com/scherbakov.al/2-c_3-g_4-off

Moved here: https://github.com/ScherbakovAl/midi_keyboard_h723