The keys on the melodeon are wired to the midi switch encoder as shown below and in the circuit schematic diagram. The first 8 keys are connected to switches 0-7 via RB0-7 and D0. The next 8 keys are connected to switches 8-15 via RB0-7 and D1. The next 8 keys are connected to switches 16-23 via RB0-7 and D2. The final 5 keys are connected to switches 24-28 via RB0-7 and D3.
| Right Hand Keys | |||
| 10 keys Key C | |||
| Switch | Key | Push | Pull |
| 0 | 1 | E(52) | A(57) |
| 1 | 2 | G(55) | B(59) |
| 2 | 3 | C(60) | D(62) |
| 3 | 4 | E(64) | F(65) |
| 4 | 5 | G(67) | A(69) |
| 5 | 6 | C(72) | B(71) |
| 6 | 7 | E(76) | D(74) |
| 7 | 8 | G(79) | F(77) |
| 8 | 9 | C(84) | A(81) |
| 9 | 10 | E(88) | B(83) |
| 11 keys Key B | |||
| Switch | Key | Push | Pull |
| 10 | 1 | D#(51) | G#(56) |
| 11 | 2 | F#(54) | A#(58) |
| 12 | 3 | B(59) | C#(61) |
| 13 | 4 | D#(63) | E(64) |
| 14 | 5 | F#(66) | G#(68) |
| 15 | 6 | B(71) | A#(70) |
| 16 | 7 | D# (75) | C#(73) |
| 17 | 8 | F#(78) | E(76) |
| 18 | 9 | B(83) | G#(80) |
| 19 | 10 | D# (87) | A#(82) |
| 20 | 11 | F#(90) | C#(85) |
| Left Hand Keys | |||
| Chord and Bass Buttons | |||
| 8 Keys | |||
| Switch | Key | Push | Pull |
| 21 | 1 | G(G(55),B(59),D(62)) | D(D(50),F#(54),A(57)) |
| 22 | 2 | E(E(52),G#(56),B(59)) | A(A(57),C#(61),E(64)) |
| 23 | 3 | G(G(67),G(55)) | D(D(62),D(50)) |
| 24 | 4 | E(E(64),E(52)) | A(A(57),A(45) |
| 25 | 5 | C(C(60),E(64),G(67)) | G(G(55),B(59),D(62)) |
| 26 | 6 | D(D(50),F#(54),A(57)) | F(F(53),A(57),C(60)) |
| 27 | 7 | C(C(60),C(48)) | G(G(67),G(55)) |
| 28 | 8 | D(D(62),D(50)) | F(F(65),F(53)) |
