Custom keyboards and split designs

Back when I was at University near Paris a friend of mine was always talking about how great his ergonomic keyboard was so good and how his typing was better. Years later I was the one doing the same about the keyboard I got. Well, here I am, again, talking about split keyboards.

Back when I was at University near Paris a friend of mine was always talking about how great his ergonomic keyboard was so good and how his typing was better. Years later I was the one doing the same about the keyboard I got. Well, here I am, again, talking about split keyboards.

As I am mostly a remote worker I usually just carry my laptop with me. And since I am a rather XL person (in Europe that is) typing on a laptop ensures that my shoulders are pointed inwards, my back arched and my breathing not as big as it could be.

When I lived in London I stumbled upon custom keyboards with a split design through a friend and As I studied electronics at Uni I was happy to do some soldering again and assemble the two halves of an Ergodox keyboard. Two other pairs followed in the next year but I am back using the first one most days.

Future doesn’t wait

In the years that have passed some people out there continued to do some more custom designs for split keyboards. You can now find a handful of them sold as kits in a few places online and a lot of other totally custom designs too.

I am quite happy that’s the case. It means that the concept is indeed appealing to more people, that design, prototyping and making of batches of such keyboards PCBs is easier than 10 years ago. That’s great because it will allow a lot more people to not only buy and make such keyboards but also other custom PCB based things. But that is for another story.

Posture, posture

As hinted above, one of the main reason I was interested in a split keyboard is the possible improvement of posture.
Laptops are made to be compact and easy to carry. So their keyboard is designed in a way to go with this constraint. Keys are close to each other, and not too big. If you are using a laptop bigger than 13 inches it’s more or less a regular keyboard size. But if you look at how your arms arch towards the keyboard you will notice your back isn’t helped to stay straight. What’s even more likely is that your shoulders will turn towards the front to get your arms the right way. All this will reduce your chest opening and hinder your breathing.
Well, in my case, that’s what happens.

So, when I saw the split design for a keyboard I thought that would be worth trying. Almost 5 years later I am still happy with this design. The model I have is a bit heavy because of the case but it’s quite great to use and I miss it when I travel so see my clients or work at a coworking space.

Back to the shops

A friend recently shared with me some links towards some custom keyboards. I found out that there has been quite some activity over the last few years in that community. Not only reduced sized custom keyboards are popular and numerous but some new designs for split keyboards have popped up too.
Among them I got interested by the Kyria design. It requires about 50 switches instead of the 76 or 80 that an Ergodox keyboard needs. So it’s quite smaller than an Ergodox. The main difference is the absence of the top row and fewer keys in the thumb cluster.

I found one main place to get a complete kit in Europe : Splitkb, a small, homemade shop maintained by Kyria’s designer. As I already have a few complete sets of keyboard keys in stock my order was a lot cheaper than the ones I did for Ergodox keyboards.


The assembly guide is pretty simple and straight forward if you have put together a custom keyboard in the past. It’s all pretty much the same : diodes, resistors, switches and controllers.
One difference I found with the Ergodox kits is the use of two micro controllers instead of one paired with an I/O expander. This has implications when flashing the firmware but I am ok with this as it gives a bit more freedom when it comes to the firmware abilities.

The new thing with this generation of keyboards, beside the micro controllers, is the use of OLED displays. A pair of these can be installed and used to display information about the keyboard status. My Ergodox keyboards use LEDs and a simple binary encoding to display the layer currently in use. Having a clear indication of the layer name on a screen is pretty nice in comparison.

Early impressions

I assembled the kit in two sessions, probably 4 hours in total. I encountered some minor issues with the firmware and the OLED screens. The gist of this issue is that the online configurator doesn’t use the default firmware to generate one with your “custom” keymaps. The firmware generated doesn’t include some code to display layers information on the OLEDs. The solution is to clone the QMK Firmware repository, add your custom keymap, compile the firmware and flash it on both micro controllers.
In many cases that’s what the user of a custom keyboard would end up doing to make some more custom adjustments so that’s not a big deal. It’s just a little bit of a surprise.

The usage of the keyboard is a bit of a struggle though as the design is even smaller than an Ergodox so proper typing is even more important. The lack of the top row is a big change as it forces me to use one row in one of the layers for this. The memory will come in fast, I think, but that’s one main issue I have currently with this 40% design.

On layers

The Ergodox keyboard was the first keyboard I used with a custom firmware. Before that I didn’t know it existed. I also didn’t know there was a possibility of having “layers” of keymaps. The idea is similar to what happens to a keyboard when pressing the Shift key. Keys suddenly have a different effect. With custom keyboards you can decide to have more than one “shift” key to have totally different keymaps available on one single keyboard. Some use it to have both Qwerty and Azerty keymaps, but most use layers to compensate for the lack of keys.
A reduced size for a keyboard is practical but it’s also a way to get rid of physical keys we are not using often. Instead, one can rely on layers to still have access to those keys (numbers, media, arrows, …) without them being physically present.
The ergodox design is fairly close to a regular keyboard. The need for layers is limited with it but can be helpful to improve typing and comfort. It was a nice introduction to these concepts for me and I have grown very fond of having such virtual extensions of my keyboard.
The Kyria design forces you to use additional layers since it has less physical keys, almost a bare minimum. I still think this is brilliant. It opens up a lot of possibilities for the user. It’s probably not for everyone (who has the patience to figure out two or more keymaps?) but it’s a nice exercise still.

Why a smaller design ?

After years of using an Ergodox keyboard I noticed that I was not using some of the thumb cluster keys that often. I also noticed how rare it was to use some of the keys in the outer columns. Most of the use for those are related to “Shift”, “Tab” and “Esc”. All the rest I already handled through a separate layer and a quick layer shift key.
I was also interested in having a smaller form factor to be able to carry the keyboard with me when working from a coworking space or travelling to see my clients abroad.
So I guess it was only a question of time before I looked into smaller designs. It was really a lucky browse that got me to find the Kyria design and purchase a kit. The fact that I already have a couple of complete keysets for Ergodox keyboards also helped. Keys are often one of the most expensive part of a keyboard, so not having to buy one helped.

What next?

I don't know if I will do another custom keyboard in the future. It’s quite an expensive hobby compared to the price of a basic keyboard in the shops and both the Ergodox and Kyria solve my current needs.
If I do it might be an Atreus keyboard or something similar. I like the idea of having a small, ergonomic, keyboard in a single block. It might come handy in some cases where I can’t use the split design of an Ergodox or Kyria. Yet, in such cases I would probably be using a laptop so I could survive with the keyboard of said laptop.
In the short term I can see myself updating my Ergodox pairs with a QMK based firmware first to enjoy some of the new features. Then I will continue tweaking the firmware and keymaps to my needs on both designs.
The Kyria feels like a good alternative to my Ergodox for both weight and usage reasons so I am quite happy with this purchase so far. If I was giving recommendations to someone discovering custom keyboards based on split designs I would indeed point that person to the Ergodox or the Kyria. I think the choice as to do with how aggressive you want to be regarding size and usage of layers.

If you are interested by custom keyboards you can start with the following links :

  • QMK firmware : the place to go to learn more about the firmware itself with reference to many different designs it supports.
  • Ergodox keyboard : the place to learn all about the Ergodox design and how to build it. You can find kits in different places through the web and the world.
  • Splitkb : the shop and home of documentation for the Kyria design in Europe.
  • Little Keyboards : An US based web shop with many kits in stock. Worth a look even when you are based outside of the US.
  • [Thomas Baart posts on QMK Firmware]([QMK – Thomas Baart] : a series of posts by the designer of the Kyria keyboard about some of the features of the QMK Firmware.

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