Keyboard Layout Design

[Glauco Schlembach]

Togive you a visual comparison, here are three clips of hands typing this python function definition. I chose the code sample by taking the popular open source library numpy and choosing a function at random as a decent representation of standard python code. Look at all the special characters!

1) me typing on my custom layout on my moonlander keyboard. I have two layers defined: an alphabetic layer which is layed out using the colemak layout, and a numeric + special char layer. You can tell when I am typing in the special character layer because the small LEDS at the top of my keyboard turn on blue while I am in that layer.

Additionally, I wanted to make sure that I could type all the modifiers in combination with one another. This meant that I could not put control in the place where I have right-arrow mapped, because I also hit that key with my left thumb, which would make it impossible to type control and command at the same time. I have command and shift next to each other, and when I want to type them simultaneously I type them both at the same time by pressing my thumb down between them.

I put my top two choices onto the outside of the thumb cluster, which is where my thumbs rest, making them the top choice key positions in the layer. I switched from using double-quotes to using single-quotes in python for strings, which let me bump double-quote down the priority list when making placements. I then mapped the next 4 top keys to the thumb cluster.

I then tried to group keys conceptually in the remaining space, again starting with the default layout and riffing on it to adjust to my uses. I order the placement of the grouped keys with the most frequent members of the grouping going on the home row, followed by the priority ordering: above home row, below home row, two below home row. Finally I filled in the remaining spaces with the remaining one-off keys.

Arithmetic Same story, I started with the default layout, but because I frequently type forward-slash (aka the divide symbol) while typing filepaths, I bumped it to an easier-to-type location on the home row rather than below it. I then moved the minus symbol to fill in the arithmetic column. Then I grouped the other slash, back-slash, into the position adjacent to foward-slash.

I wrote a bit about my experience switching to colemak here, but that was more at the level of typing tutors. I also did two things in the physical world to make learning (and iterating on) my keyboard layout easier. One was labeling the keys, made easier by the specific keycaps I bought, and the other was creating a diagram which I could look at instead of at my hands.

I first tried to label the keys in a lot of ways that did not work. I started with sticking tiny cut out post-it notes over the keys, followed by attempting to tape those on, followed by blank keycaps that I tried to label with sharpie and nail polish. None of those worked.

I printed out a square grid, labeled the squares, cut them out, and put them in the keys. Here is my grid template. If you use it check your printer resizing settings to make sure it prints at the correct size for your caps. It looks like this:

The other thing that I did that I found helpful was I printed out a blank key-map, filled it out, and color-coded it by which finger should hit which key to make it easier to read at a glance. I taped it to my monitor and looked at the keymap rather than my hands when I was going through typing tutors.

Colemak is a layout that has alphabetic keys laid out in approximately priority order, but also geared towards keeping uncommon characters in the same position as on the standard qwerty layout to make it easier to switch. Colemak in one of the pre-installed layouts on mac & linux, and easy to install on windows, so it is low-effort to install on a new machine. I wrote about my experience with switching to colemak here.

There I was; awake in the middle of the night carrying our baby in a harness, standing in front of the computer trying to learn this new stinking layout while ignoring his cute smile, hoping he would fall asleep soon.

Home-row mods is another very popular feature that would unlock a lot of extra space on the keyboard (as it would allow secondary effects on long-press instead of shifting and reduce the amount of combos I have).

And of course, if you find the idea of designing your own layout interesting or fun, you should totally do it!I honestly thought it was really fun (even though learning it was a pain).

Even simple things like adding a navigation layer (with arrow keys under your fingertips) or moving Escape are hugely beneficial.And of course, avoiding the gymnastics of pressing Ctrl in the lower left corner with the pinky is a big win.

At first it may seem there is no good reason to build a keyboard like this, other than for aesthetic purposes or bragging rights. However, there are valid arguments to be made for reducing the number of keys on a standard keyboard. If you've ever tried to learn touch typing, then you were taught the importance of keeping your fingers on the home row. Yet there are many keys that force your hand to move off the home row. Even the number row can be hard to reach for people with smaller hands.

Your mileage may vary depending on how long your fingers are, but there certainly a surprising number of important keys that require a significant stretch. This is why many ergonomic keyboards are designed with fewer keys, from the 48-key ortholinear Planck, to the 42-key split columnar Corne, to the 36-key split columnar GergoPlex. (You can of course design a keyboard with even fewer keys, but I would argue 36 keys is about the limit for a normal typing experience using the English alphabet.)

So what happens to all the keys that you lose with these smaller keyboards? The answer is to use custom keyboard firmware with layers. In same way you can hold the Shift key to access special keys keys like !, @, #, etc., you can create custom layers to access those missing keys. This does require you to memorize a whole set of inputs and potentially relearn years of muscle memory. However, it is possible to design a layout that minimizes this learning curve by following a set of principles, which we'll look into next.

That looks intense! Each thumb key activates a different layer for a total of 6 layers, so there's a lot to get used to. Furthermore, the Miryoku layout uses home row mods - the Super, Alt, Ctrl, and Shift keys are on the home row instead of the thumb keys. For example, if you hold down the T key, it will work as the Shift modifier. If you tap it instead, the letter T will output instead. This definitely makes sense in theory, as your fingers are always on the home row. In practice, it'll take some tweaking to get it to work well, as there can be timing issues where sometimes you want the modifier to activate, sometimes you want the letter to activate. This article goes over home row mods and the necessary tweaks to make it work well in meticulous detail.

This is the default layout of the GergoPlex keyboard, described in detail here. Instead of using many different layers, this layout uses combo keys to activate different symbols. For example, pressing S and D simultaneously will trigger a Backspace, pressing J and K together will trigger a colon, etc. This provides a lot of interesting opportunities; however, there can be timing issues similar to home row mods. Also, pressing combos can be tiring if you happen to use heavy key switches.

In order to build these types of layouts, you'll need to program your own keyboard firmware. A popular open source keyboard firmware project is QMK, which allows you to program layers, combos, and many more features that enable you to map all the keys necessary to a 36-key custom keyboard. (You can get an overview of how to use QMK in my previous article.)

Many people have found success with variations of the layouts described above. However, they didn't fit my particular needs, so I wanted to design something from scratch. Basically, I want to be able to switch between my 36-key custom keyboard and my normal laptop keyboard without issue. This doesn't seem to be a problem for some people, but for me, I noticed that I made a lot of mistakes reaching for the wrong keys when I switched between these different layouts. Keeping that in mind, these were the design constraints I used for my keyboard layout:

I found this to be essential if I wanted to switch between my custom layout and a standard keyboard. Many people redesign their layouts completely, using Dvorak, Colemak, or other non-QWERTY layouts. Which makes sense if your goal is to optimize ergonomics as much as possible. But that's not my goal - to me, reducing the key distance from the home row is ergonomic enough. My goal is to optimize other factors, namely minimizing the learning curve and minimizing the difficulty switching to a standard keyboard.

What this means is that the Escape key, which has to be relocated on a 36-key custom keyboard, will stay on the left side of the keyboard, the Enter key will stay on the right side of the keyboard, etc. This helps avoid any conflicts with keyboard shortcuts that involve two different hands (for example, Command Enter, which normally uses two different hands, would be difficult to execute if the Enter key was moved on the same hand as Command). I think this also helps with muscle memory, at least when I was experimenting. I tried moving the Tab key to the right hand, and my brain wasn't having it - moving it back to the left hand felt way more intuitive, even though it was a different position than normal. Again, your mileage may vary.

When making custom keyboard firmware, you can program any single key to have multiple functions. The A key can be programmed to send A when tapped, send Control when held, send Tab when double-tapped, etc. This is an essential part of making a 36-key custom keyboard feasible. However, certain keys work better than others. Overloading the A key as in this example can cause errors when you type quickly - when you type "as", it may register as Control-S or "as" depending on how quickly you release the A key. You can tweak the firmware timings, but I'd rather avoid the issue altogether by not overloading these commonly used letter keys if at all possible.

3a8082e126