ldebritto / zmk-config

ZMK keymap for 34 key Ferris Sweep based on Callum's layout with a few other tricks

Design principles

This keymap was heavily inspired by Callum's layout for QMK and is guided by the following principles:

1. Every key should have just one way to type it, the only exception is the SHIFT key that is both available as a HR mod behind a layer and a thumb key;

2. Avoid hold-taps, as they are finnicky to tweak, could misfire or require long pauses. Same reasons pointed by Callum at his readme apply here.

   • Excecption was made to accomodate GLOBE in DEF and NAV layers, at the Z key position. This allows me to trigger my window manager of choice (Swish), see #5 bellow;
   • This behavior was mirrored on NAV to make possible to trigger iPadOS shortcuts for multitasking (such as fn+control+left/right arrow to tile the app to the left or fn+up arrow to trigger the app switcher).

3. Thumbs do all the regular layer changes. Except for the special AOE2 gaming layers, &smart_mouse and &numword, that are toggled by combos;

4. Keyboard functionality (such as &bootloader and bluetooth toggles) is hidden behind combos available only in the FUN layer. This makes them purposelly difficult to trigger by accident, while still being still being accessible when needed;

5. Other combos should be convenience only, such as

   • NAV layer toggle for extended edits (left thumb keys);
   • mute (vol up and down on NAV); and
   • left hand activation of some special keys (ENTER, BACKSPACE, SPACE and ESCAPE).

6. Tap dance is used to make double press on thumb shift trigger &caps_word behavior and to combine next song and previous song into the same key on NAV.

My use case and layer design choices

Its main uses are writing prose in both English and Portuguese as well as some light coding.

1. QWERTY with changes on ' ; and / keys positions

Base layout is QWERTY with a few changes to optimize for my use case.

• On DEF, ; was moved down and made way to ' as this is far more useful to make accents and quotes in these use cases.
• / only exists in the SYM layer.

2. Longe &sk timeouts and &lc for cancelling queued mods when triggering other layers

A crazy long timeout (10m) was assigned to &sk behavior in this keymap. So there's no rush to combine mods with keycodes with keys from DEF or whatever the currently active layer.

Layer keys (usually &mo) were replaced by a custom layer-cancel (&lc) macro that taps a &kp K_CANCEL command alongside the &mo command. This cancels any previoulsy &sk queued mods on the layer key press.

This design allows for canceling mods only when invoking SYM, NAV, of FUN, while still keep them triggered when you move back to DEF.

This emulates in ZMK the LA_NAV and LA_SYM custom behaviors found in Callum's QMK keymap.

It's built with the parametrized macros as &lc to allow for easier reading of the keymap and user modification.

3. &swapper for swapping between apps/windows

Allows for CMD+TAB with just one key. It keeps the modal open until you release the layer toggle, just as you would hold CMD between TAB keypresses.

This is not native to ZMK's main repo and requires PR# 1366. See ZMK.dev documentation for instructions on how to use PRs not yet merged into ZMK's main repo.

4. Numpad for &numword

&numword is accessible through the N key in SYM layer or via a right thumbkeys combo.

This behavior allows for quick entering numbers and will disable the numpad layer upon key press of any key than a number, math symbol or BACKSPACE/DELETE. I believe this behavior was introduced to the custom mech community in QMK by Jonas Hietala. This ZMK implemenation was made by urob and I've copied with a few modifications here.

5. Apple's Globe key on mod-tap Z and ; keys

Recently ZMK implementted a keycode for emulating GLOBE/fn key on Apple's keyboards.

It's not 100% the same behavior made by Apple's keyboards (see limitations here), but it gets the job done for my uses – wich is mainly window manipulation on both macOS and iPadOS. So I've made it into a &mt replicated in DEF, NAV and SYM on the keys used by lower pinkies.

6. &smart_mouse copied from urob's repo

Yet another feature copied from urob's repo.

It is activated from the M,. key combo, from DEF layer.

Also requires PR #1366 used in &swapper behavior.

7. Special AOE 2 gaming layers

I've maped my main Age of Empires II Definitive Edition shortcuts to a set of 3 layers on the left half of the keyboard.

• This is toggled on/off via combo with WER keys from DEF layer;
• Pause (F3) is also doable within this mode by comboing XCV.