Next steps are to leverage the Arduino in the Keyboardio to interface with the TrackPoint module. Again, easier said than done, but here’s what I have so far:
The “circle” in the plastic next to the Expansion Slot pins inside the Keyboardio’s left side is the perfect spot to drill a hole to run wires through. It is just far enough from the Octopus stands to not be in the way, and just close enough to the Expansion Slot headers to run wires that won’t get pinched when the Keyboardio is assembled.
The black plastic is easily sand-able with 180 grit sandpaper, which I recommend doing to remove the protruding plastic created by the drill bit. It is very “soft” plastic and probably has a low melting point. When sanding, obviously you’ll want to protect the finish of the surrounding area with something like painter’s tape.
Alas, standard Dupont connectors will not fit with the stock Keyboardio top case. Someone else in another thread suggested cutting out some of the wood. This would work, but I don’t really have the tools to do this properly, and I am hesitant to take tools to the wood. As far as I know you can’t purchase a replacement if you screw it up (although Jesse might be able to get you one???). Anyway, this is a disappointing “oversight” in the design of the keyboard, and I can only imagine it was done for good reason.
This means that soldering to the pads on the underside of the left side PCB is the only way you’ll be able to connect anything to the expansion slots while using an unmodified top case. So far I have taken out one of the pads for one of the digital pinouts (never pull on a wire soldered to a pad!).
I have attempted to connect the TrackPoint module directly to the Keyboardio, however I seemed to have shorted D4 and D3 when I ripped off the pad and so needed to desolder the TrackPoint wires in part to ensure the Keyboardio still worked. I will probably make another attempt, however it is worth noting that there are no solder pads for 5v or Ground, only Dupont connectors. This means, as far as I can tell, you must solder 5v and Ground to the points where the Expansion Port Dupont connectors are connected to the PCB of the Keyboardio.
Also, I am not 100% sure how to integrate the TrackPoint-controlling software into the Keyboardio’s firmware. As a software engineer I have a good idea, but systems programming/C is not my strong-suit!
For now I will enjoy the fruits of my labor with the external Arduino solution.