a mechanical keyboard build, down to the firmware

I have wanted a keyboard that fits my hands rather than the other way round for years. The compromise I had been living with was a full-size board where I never touched the numpad and my right hand had to make a small journey every time I wanted the arrow keys. So I built a 60% board from a kit, soldered it myself, and flashed firmware I could actually change. This is the writeup, soldering iron burns and all.

the kit

A 60% layout drops the function row, the numpad, the arrow cluster and the navigation block, and gives all of that back to you through a function layer. The kit was the usual suspects: a PCB, a plate, a case, a set of stabilisers, and the switches and keycaps bought separately because that is half the fun and all of the rabbit hole.

I went with tactile switches rather than the clicky ones, on the grounds that I work in the same room as other people and would like to keep working in the same room as other people. The board is hot-swap-less, meaning the switches solder directly to the PCB, which raised the stakes on the soldering and meant I wanted to get the firmware decisions roughly right before committing 61 switches permanently.

stabilisers first

The single best piece of advice I was given: sort the stabilisers before you solder anything. They sit under the larger keys, the spacebar, shift, enter, backspace, and a rattly stabiliser is the thing that will annoy you every day for the life of the board. So they got clipped, lubed, and band-aid-modded before the switches went anywhere near the plate. Tedious, fiddly, absolutely worth it.

soldering 61 switches

Then the long bit. Switches clip into the plate, the plate sits on the PCB, every pin gets a touch of solder. Sixty-one switches, two pins each, so a hundred and twenty-two joints, and you really do not want to discover a cold joint after the case is screwed shut. My routine settled into: do a row, test continuity, move on.

A few things I learned the hard way:

• Seat every switch fully into the plate before soldering any of them, or you get a board with one key sitting proud and no graceful way to fix it.
• A cheap iron is a false economy. Temperature control is the difference between a clean joint and a grey lump.
• Test as you go. Tweezers shorting a switch's pins should register a keypress once the board is flashed, and finding a dead column early is far better than finding it late.

By the end the soldering was almost meditative, which is not a sentence I expected to write at switch number twelve when I burnt my thumb.

the firmware is the actual point

Here is where it stops being a soldering project and becomes a computing one. The board runs QMK, the open firmware that lets you define exactly what every key does, including layers, macros, tap-versus-hold behaviour, and the lot. You describe your layout in C, compile it, and flash it over USB.

My layout is built around a function layer triggered by holding a key that is otherwise Caps Lock, because Caps Lock is wasted real estate and sits right where my little finger lives.

#include QMK_KEYBOARD_H

#define _BASE 0
#define _FN   1

const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
    [_BASE] = LAYOUT_60_ansi(
        KC_GESC, KC_1, KC_2, KC_3, KC_4, KC_5, KC_6, KC_7, KC_8, KC_9, KC_0, KC_MINS, KC_EQL, KC_BSPC,
        KC_TAB,  KC_Q, KC_W, KC_E, KC_R, KC_T, KC_Y, KC_U, KC_I, KC_O, KC_P, KC_LBRC, KC_RBRC, KC_BSLS,
        MO(_FN), KC_A, KC_S, KC_D, KC_F, KC_G, KC_H, KC_J, KC_K, KC_L, KC_SCLN, KC_QUOT, KC_ENT,
        KC_LSFT, KC_Z, KC_X, KC_C, KC_V, KC_B, KC_N, KC_M, KC_COMM, KC_DOT, KC_SLSH, KC_RSFT,
        KC_LCTL, KC_LGUI, KC_LALT, KC_SPC, KC_RALT, MO(_FN), KC_RCTL
    ),
    [_FN] = LAYOUT_60_ansi(
        KC_GRV,  KC_F1, KC_F2, KC_F3, KC_F4, KC_F5, KC_F6, KC_F7, KC_F8, KC_F9, KC_F10, KC_F11, KC_F12, KC_DEL,
        _______, _______, KC_UP, _______, _______, _______, _______, _______, _______, _______, _______, _______, _______, _______,
        _______, KC_LEFT, KC_DOWN, KC_RGHT, _______, _______, _______, _______, _______, _______, _______, _______, _______,
        _______, _______, _______, _______, _______, _______, _______, _______, KC_VOLD, KC_VOLU, KC_MUTE, _______,
        _______, _______, _______, _______, _______, _______, _______
    )
};

MO(_FN) means momentary layer: hold it and the second map applies, so the arrows live under WASD-ish positions on my right hand and the volume keys sit under the bottom row. KC_GESC is grave-escape, Escape on its own and backtick with shift, which on a board with no dedicated escape key is the small touch that makes it usable.

Compiling and flashing is the satisfying bit. make my_keyboard:default, hold the reset, and the new layout is live in seconds. The first time I changed the arrow layer, decided I hated it, and reflashed a better one inside a minute, I understood why people fall down this hole. The keyboard is no longer a fixed object. It is a small program I happen to type on.

was it worth it

Two evenings, one burnt thumb, and a board that does exactly what I want. The typing feel is better than anything I have bought, the layout fits my hands, and the firmware means I can change my mind whenever I like. The arrow keys are under my right hand where they belong and the numpad I never used is simply gone.

If you have ever caught yourself fighting a keyboard's layout instead of using it, build one. The soldering is learnable in an evening and the firmware is where it gets genuinely good.