WeAct CH552T board, running FAK

How's my handwiring? 😅

https://github.com/semickolon/fak

FAK is a keyboard firmware for the CH55x series of very cheap chips, with the purely functional programming power of Nickel. The project aims to make keyboards much cheaper and to make configuration more declarative and fun.

New features:

• You can now make split keyboards with FAK!
• Combos of up to 8 keys that get the same treatment as physical keys
• Media keys for playback and volume control

Most importantly, three full examples are now in the repo of varying difficulties. The beginner example demonstrates how to make a simple keyboard and keymap definition and it looks almost like JSON (but with "variables").

The intermediate and advanced examples demonstrate how powerful Nickel can be. It features parameterization of keymaps and layouts, advanced home-row mods with eager decision, automatic generation of home-row mod behaviors based on their key position, and more. You can even bring your configs to a higher level of abstraction and be able to do something like this:

base_layout = "WFPBJLUYSTHKXNAIRCGDM,.O"

This, for example, defines the sequence of keys in your base layer and, since it's just a string, you can change it very easily. Somewhere along the way, this string of characters becomes kc.W, kc.F, kc.P, ... but done automatically. Abstractions like these can help make your configs more flexible and modular and they allow for code reuse across multiple keyboards and layouts (like QMK userspaces!)

I'd love to hear what you guys think! Any feedback, suggestions, and testing is appreciated! :)

Hey all! I'm excited to share and announce my open-source keyboard firmware project. FAK exclusively supports very cheap CH55x chips. You can get a CH552 for half a dollar or maybe even cheaper. No need for external flash, LDOs, or oscillators. The chip's basically a whole MCU on its own.

So far it has layers, hold-tap, and tap-dance. Split support, combos, macros, etc. and more to come. It's based on Nickel, a purely (almost) functional programming language, so FP folk can go crazy on their config and parameterize everything or whatever. But hey, you only need that kind of power if you want it. For beginners, you can start simple and it looks almost like JSON.

Home-row mods are a first-class citizen with very customizable hold-tap behaviors. There's global quick tap from ZMK. There's hold-tap flavors too, but settable per key per behavior. There's eager decision, quick tap, and more.

I've also been experimenting with other matrix scanning methods like the Cheapino's (forgot the name) and round-robin/charlieplexing. This means less pins required, so you can get away with a CH552T (instead of a CH558L with more pins, twice the price) and keep your build very cheap.

Please check it out! If you have CH552 chips around, I'd appreciate your feedback. I've yet to write better docs and a website, but feel free to DM me and I'd be happy to help you get it running!