SimLab P1X Front Mounting Button Box

Forward

This button box was designed around the P1X front mount. I'll likely update with some better pics later.

There's a lot of optional stuff shared here. You could get by with as little as the simple front plates, a few buttons and an Arduino. I happen to like the convenience in using the BBI-64 board and the support it provides for future additions.

I made two flavors for each button box being that there's likely a common difference in switchology preferences.

Left plate versions

SPST plate : The switch is cheap and common to find online and works great as a self-returning ON - OFF ignition switch. Probably the more common approach for these sorts of things. Having the switch return as apposed to remaining on is essential so that the switch remains in sync with the game.
SPDT plate : Higher quality (ON) - ON - OFF "wig-wag" switch. All this really brings to the table is an option to provide a power option to the illumination and/or functionality to the other buttons. The first throw of the switch will lock it in a position that provides power to the buttonbox, while the second throw works as a self-returning switch just like before.

Right plate versions

Double encoder plate : I haven't really tested this one out, other than seeing that the encoders fit. This is in support of having two dial encoders.
Single encoder plate : Support for a knob that's intentionally large for easier access. The encoder listed uses a self-returning mechanism that returns the knob to the center position.

Parts List

Nuts & bolts

x8 M3 15mm (secures the backplates)
x8 M3 nuts (secures the backplates)
x2 M3 10mm (secures the encoder plate)
x1 M4 grub screw (secures the encoder knob)
x4 small zip-ties (prevents wire-tug)
x2 rubber grommet (wire cleanup) ballpark specs:

20mm Groove width / hole dia
24mm OD
14mm ID
3mm Material thickness

Electronics

x6 16mm momentary pushbutton switches
Brake bias self returning rotary encoder : Alps Alpine EC1110120005, (UK link), (Potential Ali alternative)
Rotary encoder alternative: CTS288, CTS288V
SPST Ignition switch : SPST (ON)-OFF MOMENTARY TOGGLE SWITCH - 11AF
SPDT Ignition switch 6GG5B-73
Engine start : Jtron 12V 20A Push Button Switch
Potentiometer for adjusting LED brightness.

Optional BBI-64 hardware

x4 M3 nuts
x4 M3 8mm bolt
x4 M3 motherboard standoff screw

SPDT Power Schematic

    USB (+)
          |
potentiometer
          |
         +-------------------------+
         |                                            |
      (ON)                                      ON
         |                                           |
    +------+------+                      |
    |          |             |                       |
    |          |           >|                       |
    |          |             |                       |
L-LED  R-LED  Start              Ignition
    |          |             |                       |
    +-----+-------+
               |
        USB (-)

v2 Change log

Removed the backplate clamping support (the original installation was just to much trouble). The v2 version dimensions are such a tight fit, that I don't think clamps are necessarily needed.
Added a second left front plate option that supports a higher quality SPDT ignition switch.

Future

Identify and implement a higher quality engine start themed button.
Backplate mounting clamps.
Further R&D of BBI-64 mounting hardware and placement.

Credits

Remix from Peter's brake bias knob, modified to work with my choice of an encoder.