ZMK-AUTO-LAYER (ZERO-PARAM VERSION)

This module adds an auto-layer behavior to ZMK. A layer activated by the behavior continues to be active for as long as keys in a configurable continue-list are pressed, and deactivates automatically on any other key press.

This is a re-implementation of PR #1451, separating the auto-layer behavior from caps-word. As the behavior does not require any modifications of ZMK's core api, it can be implemented as a module.

Usage

To load the module, add the following entries to remotes and projects in config/west.yml.

manifest:
  remotes:
    - name: zmkfirmware
      url-base: https://github.com/zmkfirmware
    - name: urob
      url-base: https://github.com/urob
  projects:
    - name: zmk
      remote: zmkfirmware
      revision: main
      import: app/west.yml
    - name: zmk-auto-layer
      remote: urob
      revision: main
  self:
    path: config

Configuration

The behavior takes five properties:

• layers (required): An array of layer indices to activate when the behavior is triggered.
• continue-list (required): An array of keycodes that will keep the layer active.
• ignore-alphas (optional): If set, the layer will not be deactivated by any alphabetic key.
• ignore-numbers (optional): If set, the layer will not be deactivated by any numeric key.
• ignore-modifiers (optional): If set, the layer will not be deactivated by any modifier key.

Example: Numword

The following illustrates how auto-layer can be used to implement a num-word behavior that activates a numbers layer for as long as only numbers and a few other keys are pressed.

/ {
  behaviors {
    num_word: num_word {
      compatible = "zmk,behavior-auto-layer";
      #binding-cells = <0>;
      layers = <NUM>; // Replace NUM by index of numbers layer
      continue-list = <BSPC DEL DOT COMMA PLUS MINUS STAR FSLH EQUAL>;
      ignore-numbers;
    };
  };
};

References

• The behavior is inspired by Jonas Hietala's Numword for QMK
• The implementation parallels the one of Joel Spadin's upgraded Caps-word
• My personal zmk-config contains a more advanced example