Keyboard Builders' Digest
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Issue 54 / Week 47 / 2021

This is a hand-picked selection of last week's content from a keyboard builder's perspective. Posts that may teach you something, make you think and contribute to the common knowledge of the DIY builder community.

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Behind the Scenes of Issue 54

Major split database update on the way, developments, giveaway follow-up, on the UNO Mini & Adafruit KB2040 controllers, Issue #53 follow-up, Movember.

Split database update

This weekend it came to me how outdated my split database can be. It was definitely high time for a major update so that's what I did – or at least what I started to do.

Even though I've diligently posted new split designs on in the meantime, the two data tables are very different with different goals, structure and tag system – so it's not that easy to move records from kbd issues into the split list.

As it turned out, the last time I tried this was half a year ago, somewhere in May.

I started with a…


This is exclusive or early-access content for my regular supporters (members) on BMC.

If you can't afford supporting this project, don't worry, I might publish parts of these write-ups later.

Btw, the full story is 6,600+ characters long and you can read it at:


Baby Groot Keyboard

Sadek Baroudi's Baby Groot Keyboard is a cheap (or free!) split PCB with a lot of features.

The bgkeeb (stands for Baby Groot Keyboard) is a reversible 100mm x 100mm PCB with support for MX switches (no hotswap), per key led, rotary encoders, and exposes the SDA/SCL/GND/VCC lines in the form of the pimoroni trackball pins.

Given the PCB is so small, PCB prototype manufacturers will fab this for very cheap, or even free.

As of this writing, nextpcb will fab and ship this keyboard 100% for free (in green only). jlcpcb will fab and ship these for $2 (USD) – sadekbaroudi.

PCB in this GitHub repo:

Case files:

Build guide:

Parergon V2

David Barr's Parergon has only 32 keys, so no diodes are necessary.

It's got a very serious name, Parergon. I've just realised I never put it on github, should probably do that – iamnotyourbroom.

For those wondering what such a small board could be used for: the author is a developer and uses this for work.

GitHub repo:

Lergo (ex-Kyfle)

Axel Voitier's Lergo (ex-Kyfle) project is an ergo split exploration platform rather than a keyboard.

As I am looking into getting my first ergo split, I was faced with so many options that I just didn't know what I wanted actually… I could have bough a few different ones and started a collection, but my wallet said no ^^. So instead, I started to put up a custom board stack-up heavily inspired by a few projects. And it morphed into an ergo split exploration platform that I think is worth sharing with you :) – LexaAstarof.

As Axel's project evolves, it gets more and more refined. I like the amount of details put on the silkscreen (cover photo).

So this "system" features modular design using bit boards. "Removing some keys is really just a matter of snapping them away. But you can still add them back later on. Swap those encoders around as well."

The default is the Kyria layout but you can adjust the columns or each key individually if you'd like.

The thumb cluster is also reconfigurable, cluster angles shown on the silkscreen in 5° increments.

GitHub repo (untested!):


ErgoChoco is a well-documented open-source pseudosplit build by Choco617.

Named after the author's username (not low-pro Choc switches), this monoblock keyboard features 42 keys according to the Kyria column stagger, with 30° between the halves.

I'm an engineer, and true to form I'm bad at naming things. I'd heard the ErgoDox was designed by a user named Dox, and my handle is Choco617, so: ErgoChoco – Choco617.

GitHub repo:


Tenalice Ambidextrous

The Ambidextrous by Cerbekos is a new member of the Tenalice family, with a 45° numpad in the center of the board.

Somehow, Japanese keyboard enthusiasts are way overrepresented among my Twitter followers so I'm quite exposed to all the cool stuff happening there.

My only problem is, I have a hard time to figure out if what I see is a new and original design or simply a photo of something being around for a while.

Regardless, the Tenalice Ambidextrous showed up in too many posts recently to raise my attention.

The Ambidextrous is the latest revision of Cerbekos' Tenalice (tenkey + Alice) Alice style monoblock keyboards with a number pad between the angled halves.

While the numpad angle of the previous version indicated it was designed with right-handed users in mind, the tenkey part of the Ambidextrous is positioned perfectly symmetrically in the center, in 45°, so you can reach it with the same effort regardless of your dominant hand.

As far as I can tell, the project is only partially open-source: the plate and stacked case files are public, but I couldn't find the PCB files. Kits are available on Booth.

Much more info and insight into the design process in Cerbekos' blog posts.

E.g. here is a comprehensive build log:

And another great build log by @mikumo:

Arisutea variants

The Arisutea is a set of Alice-like layouts open-sourced by mattjames03.

As a result of his journey to recreate an Alice-like keyboard, mattjames03 published the source files of different Alice variants plus a case.

The layout was originally created by FateNozomi, inspired by Lyn's EM7 and TGR Alice with some modification. The layout was then modified by CorruptedJef and robotictomato to add USB-C, ESD and to shift/add some keys. This inspired me to modify the layout further by adding the ability to swap your switches out whenever you want and to make some keys a little more permanent – mattjames03.

At the time there are 3 variants and a stacked acrylic case in 2 different styles.


Arduino UNO Mini

The UNO is not your typical keyboard controller, but the anniversary edition is actually only 34.2mm x 26.7mm. Hmmm.

The UNO has now sold over 10 million units, and people at Arduino celebrate this achievement with introducing a miniature redesign, to be produced in limited number (however, I couldn't find any info on the exact number of boards being made).

A real UNO was my entry to DIY electronics so I'm quite sentimental about this milestone.

While building a keyboard based on a classic UNO is absolutely feasible, I've seen only one such board if I remember right.

No wonder: the Atmega328P doesn't have native USB HID support, and the board itself is simply too bulky to fit most keyboard cases, especially splits.

Still, not so long ago, questions like "Can you use an Arduino Uno/Micro to build a keyboard?" were regular ones on r/mk.

And the exposed through-hole designs built on the 328P demonstrated that, while it's not the easiest way, it indeed can be used as the brain of your keyboard.

So while it still lacks native HID support, the anniversary UNO Mini with its way more keeb-friendly 34.2 x 26.7mm footprint is definitely something I expect to see at least in a few upcoming one-off builds.

(Just as reference, the Pro Micro footprint is 33x18mm and that of a Teensy 2.0 is 31x18mm.)

Well, such a build would be still apparently a joke/fun build mostly because of the hefty price tag. For the same $45/40euro (plus shipping and VAT) you can still buy 8-10 Pro Micros from Aliexpress or 5 Keeboars from Adafruit.

Adafruit KB2040 Kee Boar

An RP2040 based development board by Adafruit, designed with keyboard builders in mind.

The first batch being sold out practically in a single day, these Adafruit Keeboars proved to be an instant success.

KB2040, Keeboar, Kee Boar, whatever. If you are not quite sure what I'm talking about, it's a brand new controller board by Adafruit, a Pro Micro alternative featuring the Raspberry RP2040 chip, and designed for keyboard enthusiasts.

I signed up to the notification a few days ago in the Adafruit store and the mail came yesterday at 18:00 (CET): "the Adafruit KB2040 is restocked and there are 235 units available".

Today, checking back at the same time, there are only 18 left. (As of writing this update, the item is out of stock, however, I was told it is restocked each day.)

Unlike Arduino's UNO Mini, Adafruit designed this board with keyboard builders in mind. If the KB(!)2040 codename or the "Keeboar" nick wouldn't make this clear, all the marketing materials refer to this one as a controller dedicated to keyboard building:

A lot of folks like using Adafruit parts for their Keeb builds – but with the ItsyBitsy not being pin-compatible with the Pro Micro pinout, it really wasn't very easy without some sort of adapter plate – Adafruit.

With dimensions identical to the original Pro Micro footprint (18x33mm), USB-C connector, 18+2 GPIO pins, castellated pads, and the RP2040 chip (datasheet) we now have a Pro Micro on steroids for $9.

Theoretically enough for a 100-key keyboard matrix, just like an "upgraded" Pro Micro, but with way more juice.

The RP2040's 32-bit Cortex M0+ dual cores running at 125 MHz, the 264 KB RAM and 8 MB SPI FLASH chip for storing files may seem an overkill but they come in handy when using CircuitPython and its more user-friendly workflow.

The code can be changed with any text editor which makes it super easy to update your keymap and customize the functions of your keyboard. No need to download any software, use online tools or setup a local development environment.

We mixed together what we liked most about the SparkFun Pro Micro RP2040 (Qwiic / STEMMA QT I2C port on the end, so good!) and Elite-C (castellated pads & pins for D+ and D-) and our existing RP2040 boards (boot button can be used for user, 8MB QSPI flash, onboard NeoPixel, jumper for skipping the diode/fuse for high power RGB LEDs or USB hosting). We even got it to all fit on a 2-layer PCB with 7/7 routing – just needed to make the smallest caps and resistors 0402.

The price? Well, $9 vs the Pi Pico's $5 for the Pro Micro footprint? You should decide if it's worth it.

Thanks to Phillip from Adafruit, one of these beasts is on its way to the HQ so hopefully I will be able to test it thoroughly in a few days.


Zealio V1 Redux

ThereminGoat reviewed the Zealio V1 Redux switches.

This week, ThereminGoat looked at the revival of the OG Zealios V1 stems in the new Zealio V1 Redux switches.

The big question was whether or not these really stack up as a true representation of the original switches "that kicked off the entire modern switch scene".

The Zealios V1 Redux switches really do mimic many of the good, worthwhile features that the original Zealios V1 switches had while improving on some of their less savory issues. Mind you, these switches are still far from perfect, and even with a revival of the ergo-clear-like tactile bump and an improvement on the overall stem wobble in this Redux, issues with spring ping and scratch have been proven to be fixable by Gateron recently, but somehow not yet for Zeal and his switches – ThereminGoat.

Full article:

Tips & Tricks

Splatter painted keycaps

Human_Evolution shares his experiences with splatter painting a keyboard in the '80/90s style.

Inspired by guitars and sneakers splatter painted by Phil Collen, lead guitarist of Def Leppard, (who was inspired by Jackson Pollock btw), Human_Evolution spent a fun day with his daughter using a similar technique on keycaps.

The method:

While wearing rubber gloves I put a small blob of acrylic paint about the size of a pea or less onto my index fingernail, then simply flick and repeat from many angles.

I just need to find a clear coat that feels good to touch, something about as smooth as plastic. Right now I have a flat clear coat and it doesn't feel that great.


  • Rust-Oleum Gloss black spray paint.
  • Americana Neon acrylic paint, scorching yellow and sizzling pink.
  • Rust-Oleum flat clear coat.

I tried so many things. Rust-Oleum clear coat, testors top coat, pledge floor polish (recommended as a light protection coat on model forums) the list goes on and on. I finally just ordered spray max 2k clear and gave it a nice even coat every 15 mins or so until it was fully coated thick and the can was empty for some mice I did. Everything else I tested over 6 months rubbed off. Be sure to read up well on it and have a nice rattle can technique because the stuff is what is used on automotive and has like a 12 hour realistic pot life.

How long did the project take?

It was an all day event. I had to wait for paint to dry and I test out different paints. If the base paint was not gloss, it would just suck up all the vibrancy from the neon acrylics, a gloss base was crucial, flat and satin base coats had poor results. I may have learned a technique that will make my next project a little better as well. I found that if you use Rust-Oleum 2x gloss spray paint and then add acrylic while the Rust-Oleum is still curing, the acrylic and the Rust-Oleum enamel fuse into 1 layer. It looks somewhat professional and may nullify the need for a clear coat. I'm interested to see what it feels like to type on once fully cured.

And the inspiration:

Fun fact: Phil Collen is color blind.

Keyboard Spotting

Tektronix 4014-1

A battered Tektronix 4014-1 computer terminal spotted by Jaceveldhuis.

This once kick-ass specimen, spotted by Jaceveldhuis with a metaphorical garbage bag standing next to it, apparently served its turn. Somebody should really rescue it.

The Tektronix 4010 series was a family of text-and-graphics computer terminals based on storage-tube technology. This means they had no memory (extremely expensive in those times) and no additional electronics were needed to maintain the display on the screen, what made them much less expensive than contemporary terminals, such as the IBM 2250.

Images drawn to the screen of this kind of terminals remained there until deliberately erased.

Several members of the family were introduced during the 1970s, the one on the photo is a 19-inch 4014. According to the Wikipedia entry, they were widely used in the computer-aided design market in the 1970s and early 1980s.

ADDS Viewpoint A2

An ADDS Viewpoint A2 acquired by Eragaurd.

An ADDS Viewpoint A2 terminal keyboard by Keytronic with foam and foil switches.

More info and some reverse engineering goodness in this Deskthority thread:


FinnGus keyboard kit

FinnGus is a cat shaped 3D printed through-hole FR4 Alice style kit inspired by the cats (Finn and Gus) of JackPikatea.

This keyboard kit has been heavily inspired by Jack's cats Finn and Gus.

The special 3D printed cat shaped case had to be printed in 3 sections on his biggest printer.

I made this with that [being ridiculously impractical] in mind, but after using it for a month now, it's actually a lot better than I expected. Sure it's large and that is a downside but other than that, it's a great keyboard and great layout. Plus built in wrist-rests! – Jack Pikatea.

More pictures:


The Uncokeeb by bluesocarrot is a per-finger chorded keyboard concept prototype.

The Uncokeeb v0.3 is a modular, 8-key per finger concept keyboard with 28 chorded states per finger module (including off).

According to bluesocarrot, it's called the Uncokeeb because it makes you feel extremely uncoordinated while learning it.

It's a little bit inspired by the Datahand, and is mostly a response to stenography.

It features per-finger PCBs with 2 top-side buttons, 6 under-side buttons, GPIO expander and Adafruit qwiic connector.

More info on the concept, inspiration and some specs in the original thread.

That was Issue #54. Thanks for stopping by.

This issue was made possible by the donations of:, Jeremy Kitchen, AikenJG, @keebio, Timo,, @kaleid1990, u/chad3814, Eugenie, sebastian siggerud, cdc, Jim,, kiyejoco, faso, _qdw_, Bob Cotton, Aleks

Your support is crucial to help this project to survive.

Discussion over at r/mk!