ζ Zeta Keyboard
A full on-screen keyboard for handheld Linux. Every key the built-in one leaves out, driven by the controller, in both desktop and gaming mode. Running on SteamOS and CachyOS today.
The problem
These are handheld computers, and people use them as computers. A terminal, a config file, a password field, a modded game, a file manager.
The built-in keyboard runs out of keys. No Escape. No function row. No Ctrl, no Alt, no Super. No Home or End. No Delete, only Backspace.
Steam’s carries a dedicated Paste button, because there is no Ctrl to press. The usual answer is to plug in a keyboard, which defeats the point of a handheld.
Every key
Esc · F1 through F12 · Tab · Caps · Ctrl · Alt · Super · Home · End · the arrows · the full symbol row · a number pad.
Every key is reachable from the controller. The bindings are printed on the keycaps, so nothing has to be learned or looked up — L5 for Escape, R4 for Tab, L1 for Ctrl.
Both modes
- Desktop Mode — anchored as a system panel, so the window above stays usable instead of being covered
- Gaming Mode — works under the console-style compositor, where most software cannot draw at all
- Keystrokes arrive as a real keyboard, through the kernel, so every application accepts them without knowing anything about this one
Both modes are named the same on SteamOS and on CachyOS, and it works in both on each. Going through the kernel rather than a desktop environment is why — nothing about it is tied to one distribution’s choice of compositor or toolkit.
How it is built
No third-party code. Not a library, not a runtime, not a framework. The display protocols, the renderer, the controller decoding and the typeface are all our own work.
It reads the controller directly and presents a virtual keyboard to the system. It records nothing and transmits nothing — there is no network code in it beyond a loopback connection to the platform's own interface, and no server behind it.
Availability
Zeta Keyboard is finished and unreleased. It runs on the hardware today and nobody else has it yet.
It is offered through distribution partners rather than sold direct. If you make hardware, accessories or software for handheld Linux — whichever distribution your users run — and this fits what you already sell, write and say so.
Zeta Keyboard is an independent work and is not affiliated with, endorsed by, or sponsored by Valve Corporation.
contact@zetasystemsllc.com