While not the first attempt at a keyboard with screens in the keys, the PolyKybd by modder Thpoll is first one I can actually picture myself or the wider public using in earnest in the future. And as a recent split keyboard convert, I'm especially on board with this project.
The PolyKybd is a mechanical split keyboard with OLED displays inside of the keycaps. The idea is to have a keyboard with universal language support, by having the keys switch over to any language. Since it's OLED, the letters and symbols on the keycap will come out ridiculously bright, making them easy to read under any lighting.
Thpoll has posted about the difficulty of adding glyph rendering for languages that use Japanese, Korean, and Arabic symbols. "To truly support multiple languages, I have to handle characters beyond ASCII-⅞," Thpoll wrote. Thpoll explains that any keyboard layout, including macropad and Stream Deck-type layouts for uses outside of typing, is possible.
The PolyKybd can support numerous mechanical switches; The little OLED displays are connected via these thin flex cables that do not add too much weight to keys. The keycaps are actually from cash registers, so I'm curious how it feels to type on the PolyKybd. When I think about superior typing experiences, cash registers don't really spring to mind.
The case for PolyKybd was 3D printed, while most other components, like the PCB, flex cables, and connectors, can easily be sourced online. If you're looking to buy a PolyKybd, Thpoll told a user on Ko-fi that he's "trying to put a kit together" to sell but said production costs would force him to sell them for over $200.
As of now, the hardware development is nearly done, according to the project log. Next, Thpoll is looking to add trackball support to the PolyKybd, and they're also working on a tenkeyless version with the number pad as a standalone addon.
