Has the expansion port type & pinout been published anywhere as of yet?
I’m looking to do some experimentation on wiring in a trackball and want to at least make sure power draw & communication for the sensor is okay before I get too involved in it.
1 Like
This tweet shows that, at minimum, early revisions had the expansion port pinout silk screened onto the PCB. Don’t know if that is still true though.
2 Likes
Ahh, yup, looks like that’s still there on my version at least (Model 01-Q). I had it apart before (getting the top case back on is a good time, but some nylon guitar pick-like thingies I had from an ifixit toolkit made it much much easier when I finally thought of using them) but hadn’t detached the board/plate assembly from the bottom case. Here’s some clearer pictures:
I wouldn’t guess the pinout has probably changed between production revision but if you don’t have a 01-Q probably worth checking for yourself before you plug anything in.
Connectors are just standard .1" headers, looks like. There’s also separate things for most of the controller pins (female headers), and the controller SPI pins (male pins, on the left when viewed from the top), as well as the ATTiny SPI pins (male pins, on the right when viewed from the top.)
Easiest way to route a cable out of the case is probably just to drill a small hole in the plastic case on the bottom, plus that way you don’t have to mess with your gorgeous topcase. There’s a little bit of room left in the wood case on the inside to make it possible to easily attach things to the expansion port, it looks like.
Anyway, easy SPI attachment is possible, looks like, and I’d guess none of those analog pins are being used either so it looks like I can do what I wanna do pretty easily.
4 Likes
There isn’t enough clearance for male or female dupont connectors with the stock wood top case. So to connect wires securely to the ATTiny/Expansion Port/ATMega pins, you’ll have to solder em.
There might be a right angle dupont connector of some sort out there that may work, but I haven’t found any. I am a bit disappointed at how inflexible the stock top and bottom case are in the way of modifications. A little extra routing on the topcase would make enough room for standard dupont connectors. Perhaps that extra wood is needed for certain structural integrity requirements? Still, it would have been nice if the bottom case came with a small hole for running wires out of. Not a big deal since drilling a 1/4" hole is super easy. On the left side black plastic bottom case, there is a circle that lines up with the reset button on the PCB next to the expansion port, this should be a good outline for where to put the hole. It’s not in the way of the octopus feet at any position, and the top and bottom case do not obstruct it when the keyboardio is assembled, making it perfect to run wires through.
I just picked up a second hand Model1 and love it.
I don’t have much experience with this hardware, but before I head off down the rabbit hole, I was wondering if anyone more knowledgeable than I could tell me if it would even be possible to add bluetooth HID by attaching a module to the expansion port, and using a battery bank attached to the USB-C port for power?