All HobbyCNC boards can be ‘adapted’ to an electrical configuration that is consistent with the ideal input type best adapted to interfacing with microcontrollers like the Arduino or Raspberry Pi (or any other, for that matter). The schematic below (Figure 1) shows the ideal layout for interfacing 5 buttons into a microcontroller.
Figure 1. “ideal” switch layout for microcontroller input.
The important design element is the one common ground that touches one side of EVERY switch. The other side of each switch is brought to it’s own, individual pad/connector.
Most microcontrollers provide internal “pull up” resistors on their input pins. The switches, as wired in the schematic above, when pressed, will “pull-down” to ground the voltage on their respective microcontroller input pin.
There are more complex ways to accomplish this (e.g. multiplexing), but for only 5 buttons, a complex approach is not practical.
Figure 2. Example of a DIY conversion using an Arduino.
All of the 6-pin HobbyCNC boards (GH-03, 04, 05, 06 11, 12 and 14) are already in this ‘common ground’ configuration, and therefore require no special adaptation.
The remaining, 8-pin HobbyCNC boards require minor jumpering of pins to create that ‘common ground’ design.
This information will apply to OEM boards too. The HobbyCNC boards are a 1-to-1 pinout match to their respective OEM Boards.
Start by referencing the Selection Guide and find which GH board is the ‘match’ for your OEM board, then return here for wiring instructions.
REMEMBER: the numbering on the HobbyCNC boards may appear backwards from the OEM board, but that’s because our circuitry is on opposite sides of the board – OEM circuitry is on the same side as the fret buttons, HobbyCNC circuitry is on the side away from the fret buttons.
GH-01 |  | 1 - Ground 2 - Ground 3 - Blue 4 - Ground 5 - Orange 6 - Yellow 7 - Red 8 - Green |
GH-03 |  | 6 - Ground 5 - Orange 4 - Blue 3 - Yellow 2 - Red 1 - Green |
GH-05 |  | 1 - Green 2 - Red 3 - Yellow 4 - Blue 5 - Orange 6 - Ground |
GH-07 |  | J1.1 - Ground J1.2 - Blue J1.3 - Ground J1.4 - Ground J2.1 - Orange J2.2 - Yellow J2.3 - Red J2.4 - Green |
GH-09 |  | 8 - Ground 7 - Ground 6 - Ground 5 - Orange 4 - Blue 3 - Yellow 2 - Red 1 - Green |
GH-11 |  | 1 - Green 2 - Red 3 - Yellow 4 - Blue 5 - Orange 6 - Ground |
GH-14 |  | 1 - Green 2 - Red 3 - Yellow 4 - Blue 5 - Orange 6 - Ground |
GH-16 |  | 1 - Ground 2 - Ground 3 - Ground 4 - Orange 5 - Blue 6 - Yellow 7 - Red 8 - Green |
GH-02 |  | 1 - Ground 2 - Ground 3 - Blue 4 - Ground 5 - Orange 6 - Yellow 7 - Red 8 - Green |
GH-04 |  | 6 - Ground 5 - Orange 4 - Blue 3 - Yellow 2 - Red 1 - Green |
GH-06 |  | 1 - Green 2 - Red 3 - Yellow 4 - Blue 5 - Orange 6 - Ground |
GH-08 |  | 8 - Green 7 - Red 6 - Blue 5 - Yellow 4 - Orange 3 - Ground 2 - Ground 1 - Ground |
GH-10 |  | 1 - Green 2 - Red 3 - Yellow 4 - Blue 5 - Orange 6 - Ground |
GH-12 |  | 1 - Green 2 - Red 3 - Yellow 4 - Blue 5 - Orange 6 - Ground |
GH-15 |  | 1 - Ground 2 - Blue 3 - Ground 4 - Ground 5 - Orange 6 - Yellow 7 - Red 8 - Blue |