i75 keyboard. 9x9 matrix.
Multiple controller options. Arduino Pro Micro, Teensy 2.0, TeensyLC/3.2
Teensy 2.0 Pinout
Cols C6 C7 D6 D7 B5 B6 F7 F6 F5 Rows D3 D2 D1 D0 B7 B3 B2 B1 B0