QMK keymaps and custom keys

I recently decided to get a new keyboard, as I have been typing on my notebook until now. I’ve aways been interested in mechanical keyboards, but haven’t been willing to break the bank for parts I’d even solder myself. Being more of a software guy, I started out by looking at firmware, specifically QMK.

Finding a keyboard #

I browsed the list of supported hardware specifically to find a complete build that I can upgrade break open and flash with QMK, i.e. a regular consumer keyboard that uses an Arduino Pro internally.

I decided on a Durgod K320 with Cherry Brown switches. It comes with an US ANSI layout and comes apart without too much of a fuss, although very solidly built. The initial flash was easy enough, and from then on a magic key combination is available to enter flashing mode.

The good stuff #

Coding your own layouts into your firmware has some advantages. I’ve done the usual things of fixing annoying LEDs and removing unwanted functionality, but here are some of the more fun ones.

Mouse Mode #

QMK supports mouse keys, which I toggle using two different actions:

• LT(_MS, KC_ESC) on my escape key, which makes it act as escape when hit, but enables mouse mode when held down
• TT(_MS) on my so-called context menu button (left of right control), which enables mouse mode on a double tap (to prevent accidental presses)

Mouse mode itself is an assemblage of different key maps on an otherwise blank layer. It basically maps WASD, HJKL and the arrow keys to mouse movement, with somewhat ergonomic mouse button locations when using either of these options. You can see the full layer here.

Umlauts #

I’ve always had Caps remapped to Escape in software, but using QMK I can repeat above trick of holding down this new escape key to access a Umlaut layer. Umlauts are fancy vowels with two dots, i.e. ä, ü, and ö, that are equivalent to ae, oe, and oe respectively¹. Using this, I could easily type them as Caps plus the base vowel. However, I still find myself using the international alt key mappings that generally come with Linux, i.e. right Alt plus Q (ä), plus Y (ü) and plus P (ö).

Additional extra keys #

I’ve always liked having my window manager act on keys such as XF86VolumeUp. Laptops often come with a whole load of extra ones on their keys upwards of F7. At first I was stumped on how to map them, but using some rather arcane tables and some trial and error, I’ve found the following ones to work reliably. I can just define those keys to emit F20 for instance, and I get to use the valuable XF86AudioMicMute in my window manager. As you can see on any product image, Durgod printed audio mute, lower and raise volume on F5 to F7. F8 however has been neglected and remains without a print, but it is predestined to be mapped to F20.