@foone I sometimes think about makeing a keyboard with the only outstanding features that it is connected over usb3/4 pumping hid date at 5-40Gbit/s. And probably the easiest way to get usb4 would some powerful CPU.
@foone The sol 3 has two stm32 inside (it's a split keyboard so one on each side). It's fun because only one really is used at the same time (the other acts more as a muxer to send keys to the primary one through serial). But both are fully capable of acting as the primary, so you can flash two different firmwares on them, and depending on which side you plug in you kind of have two different keyboards.
It also means you need to always plug in the same side if you want to keep the same configuration.
@foone
Probably the art lebedev keyboard with a screen per keycap, but i dont know if those actually exist. (I don't think I've ever seen a keyboard with enough onboard compute to need a cooling fan, for example :)
@Matt I mean, that's probably not THAT uncommon these days. So many keyboards were designed around Teensy 2.0++ or Teensy LC boards, and now that you can't get them, Teensy 4.x is the closest replacemetn
@foone I was going to say it had to be the Optimus Maximus, but insanely that didn't have any onboard computing and the host CPU had to run all of those damn screens.
Like, slab computers like the c64 don't count. I'm defining "keyboards" something like "devices intended as input devices for other bigger computers, which have over 26 buttons"
that uses a Pi Zero to emulate a keyboard and has examples from the command line. So the host half of this at least has been successfully done at least once.
@foone regarding Raspberry Pi working as keyboard and input device, there's USB4VC: a board that let you connect modern USB (and bluetooth) input devices (keyboard, mouse and gamepad) and then the Raspberry Pi emulates old protocols for vintage computers: e.g. PS/2, AT or XT keyboard, PS/2 or Serial mouse, and Gameport joystick.
(With optional remaping, i.e.: USB gamepad input events are mapped to key presses. Though that specific combination fails the 26 buttons criteria you mentionned)
(trying to keep track of my hobbies, while in charge of core software component for epidemy tracking and having the attention span of a goldfish is hard).
@foone there is a raspberry pi 400 which is an actual rPi in a keyboard (i've got one next to me as I type this), so it's not impossible.. but DIY sounds much more fun.
(FWIW, I'm becoming very keen on a Z80 in a keyboard form again, after many decades without one ;) )
@foone not yet, I’ve just been noodling so far, but I’m gonna try and get it done very soon. It occurred to me to include as part of a completely different project of converting that old keyboard I like into one that can connect via Bluetooth and ideally represent itself as at least 3, but maybe an arbitrary number of separate keyboards, so I can connect it to all of my (BT supporting) computers and switch between them. Adding the Pi while I’m in there anyhow just seemed logical somehow. There’s plenty of room inside for the pi and the esp32 I’m planning to use for the Bluetooth part.
@foone excluding projects that use general-purpose stuff like raspberry pis, my serious guess at an answer to this question is one of Art Lebedev's OLED button keyboards
@foone what about high end synths? Digital synths are all computers these days, but they are also a keyboard that provides MIDI for use on another synth or a computer. Many of them are used hooked up to a DAW these days.