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 G | |||
| Switch | Key | Push | Pull |
| 0 | 1 | B(47) | D(50) |
| 1 | 2 | D(50) | F#(54) |
| 2 | 3 | G(55) | A(57) |
| 3 | 4 | B(59) | C(60) |
| 4 | 5 | D(62) | E(64) |
| 5 | 6 | G(67) | F#(66) |
| 6 | 7 | B(71) | A(69) |
| 7 | 8 | D(74) | C(72) |
| 8 | 9 | G(79) | E(76) |
| 9 | 10 | B(83) | F#(78) |
| 11 keys Key D | |||
| Switch | Key | Push | Pull |
| 10 | 1 | F#(42) | A(45) |
| 11 | 2 | A(45) | C#(49) |
| 12 | 3 | D(50) | E(52) |
| 13 | 4 | F#(54) | G(55) |
| 14 | 5 | A(57) | B(59) |
| 15 | 6 | D(62) | C#(61) |
| 16 | 7 | F# (66) | E(64) |
| 17 | 8 | A(69) | G(67) |
| 18 | 9 | D(74) | B(71) |
| 19 | 10 | F# (78) | C#(73) |
| 20 | 11 | A(81) | E(76) |
| Left Hand Keys | |||
| Chord and Bass Buttons | |||
| 8 Keys | |||
| Switch | Key | Push | Pull |
| 21 | 1 | D(D(50),F#(54),A(57)) | A(A(57),C#(61),E(64)) |
| 22 | 2 | B(B(59),D(62),F#(66)) | Em(E(52),G(55),B(59)) |
| 23 | 3 | D(D(62),D(50)) | A(A(57),A(45)) |
| 24 | 4 | B(B(59),B(47)) | E(E(64),E(52) |
| 25 | 5 | G(G(55),B(59),D(62)) | D(D(50),F#(54),A(57)) |
| 26 | 6 | C(C(60),E(64),G(67)) | C(C(60),E(64),G(67)) |
| 27 | 7 | G(G(67),G(55)) | D(D(62),D(50)) |
| 28 | 8 | C(C(60),C(48)) | C(C(60),C(48)) |
