Keyboard Builders' Digest
Save 5% at Divinikey! Code: KBDNEWS

Issue 74 / Week 16 / 2022

This is a hand-picked selection of last week's content from a keyboard enthusiast'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 74

On longer format articles, 40 discount codes, keyboard lexicon update, duplex matrix cultural dissonance, Datalux acquisition, etc.

Hey y'all,

Welcome back for another edition of Keyboard Builders' Digest (this time Issue #74), a weekly roundup of this DIY keyboard focused newsletter and blog from Tamas Dovenyi – that's me. If you are new to this, you can read how this started out and what this is all about nowadays. If you like what you see, you can subscribe to the newsletter (free) and donate some bucks to keep this otherwise free and ad-free project alive.

Let's jump right in.


First off, thanks to everyone who contacted me with suggestions and submissions last week. I try to answer each inquiry but things really start to get out of hand. If you feel you are ignored, just give me a couple of days or simply send me a reminder. Most likely I'm busily working on another write-up or looking for your message…

No kidding, the other day I spent a considerable amount of time just to find a message I knew I received. The question was though: on what platform? I checked the email account, my twitter messages, reddit chat and PMs, discord, etc. Before checking keebtalk, geekhack and deskthority, I eventually found it in my private email inbox… And people keep asking why I'm not on viber/whatsapp/telegram/facebook, etc.

High-effort posts

My observation is that the more time and effort I put into an issue and the more kick-ass I think it is, the less upvotes it generates on r/mk. :D

According to this well-established folk wisdom, this particular issue has to be almost fully ignored on r/mk because I've spent many hours with preparing some of the write-ups.

Jacqueline's Lily notebook keyboard, the PRK firmware or the 1800-ish wooden ortho recquired a lot of correspondence, editing and/or research. And for the LDSA post I had to comb through a whole Discord channel started in January…

I hope some of you appreciate this work.

Weekly rediscovery: keyboard lexicon

Thanks to @hasumikin, who I've exchanged a few PMs with preparing the piece on the PRK firmware, I rediscovered my long forgotten keyboard lexicon.

He asked me to include his PRK, and I realized I can't even remember the last time I updated that side-project. Checking the files it was almost a year ago…

Now I included some keywords like RP2040, some new controllers, keycap profiles, and ofc PRK. ;)

Weekly discovery: duplex matrix ambiguity

Again, while compiling the PRK write-up, I contacted @policium as well, and while chatting it turned out that we use the term "duplex matrix" for two totally different matrices.

This topic seems to be a really good contender for another article – an interesting topic both culturally and technically, but I have to educate myself in this field before I can cover some more sophisticated matrices properly.

As a teaser: did you know a vanilla Pro Micro is capable of handing more than 300 keys? This was something totally new for me as I always thought 81 keys are the limit for a PM (with 18 pins) – or 100 keys by utilizing the LED pins.

But that's apparently not true. With more complex matrices you can control 160+ or 300+ keys with just 18 GPIO pins. More on this later. Stay tuned.

New supporter

Christian Mladenov is a new regular subscriber. Thanks Christian! Recurring donations like this one keep this project alive.

Vendor directory

Welcome Keebz N Cables, a relatively new shop in Perth, Australia – serving keyboard enthusiasts in/from "one of the most isolated cities in the world".

And I'm preparing a new page with all the discount codes here (WIP):

At the time of writing this, 40 keyboard shops offer discounts for my readers, and these 5-10% discounts options are now presented on a single page.

(Other than that, from the total 40 cooperations, I get a small commission for your purchases in 6 cases. I just checked it and in the recent year I earned about $13 payouts. :D)

Btw, I'm working on the standardization of the promo codes, but with most vendors this requires a manual update on their part so it's a quite slow process, espcially during the Easter recess.

Regardless, turning all the codes into "KBDNEWS" would make it possible to check this code on any shops without much thinking.

New acquisitions

I won the bid for a NOS Datalux spacesaver keyboard – allegedly one of the worst keyboards of all times! :D That sounds like a must-have in any decent keyboard collection…

Still on its way, but here is a photo from the listing with the strange slope and the inexplicably raised Enter key:

Pic: Datalux


And here is Chyrosran's rant/review from 2019:

Mine will be an AZERTY one so even worse for my purposes I guess. :D

Weekly distraction

Spotting a Kaypro II in a Twitter thread by Huxley Dunsany I ended up looking for text adventure games… Like this one: Eventually, although not a text adventure, I rediscovered Maniac Mansion, a game I spent a lot of time with as a child. You can play it here. ---

That's all folks. Feel free to comment in this issue's r/mk thread, and as always: keep learning and building.

Cheers, Tamás


Custom Reform keyboard

Jacqueline designed a custom ergo keyboard for her Reform laptop – based on the Lily layout.

[Ed.: Jacquelin's (aka @cooljqln) DIY split laptop keyboard, a self-designed replacement version of the open-hardware MNT Reform laptop's stock keyboard, was brought to my attention by fellow Redditor cdc_mkb. (Btw, the MNT Reform keyboard was featured in KBD#59.) I asked the designer for some supplementary info and she was kind enough to write about her project in detail. So let's hear about the inspiration, her background in the hobby, and the whole design and building process in her own words.]


I’ve been really inspired by the MNT Reform as a platform for doing weird things with technology. I know there’s a few different takes on the ‘repairable’ laptop floating around, and there have of course been previous attempts at open hardware laptops. But the Reform has been the first one to really capture me, due to its combination of looking like a real product whilst still being totally open in a hackable way.

Pic: My Reform motherboard, before doing anything to it!

My Reform motherboard, before doing anything to it!

By ‘a hackable way’ there, I mean… think about mechanical keyboards. You can just buy an off-the-shelf keyboard, sure. You can also get a DIY kit, or get your own components made using the open source design files, or design your own thing from scratch. It’s 100% down to what you want to do, from an artistic and engineering perspective.

The Reform, to me, offers that kind of complete freedom, but on a complete system scale.

Want a different keyboard layout? Easy, just get a new PCB made! Want to do something weird with the case, like a fun colour, or space for an external antenna? Again, it’s easy! I literally made my own touchpad for this thing based on the design that MNT released (and it works GREAT, too!!)

In my case, because my Reform build is a completely DIY project, I was even able to modify the motherboard to use USB-C PD rather than a DC barrel jack for charging.

Compare this to similar projects that are superficially in the same space – the framework laptop is the most obvious one – and it’s clear that the Reform is just on a completely different level.

I find it all very exciting :)

Background & previous projects

So I, somewhat worryingly, had embarrassingly little electronics knowledge before deciding to build a laptop from scratch.

I’m a Senior Software Engineer at Big Tech Company You’ve Heard Of, so a lot of electronics and firmware stuff has been kind of adjacent to things I work on. But my first real electronics + keyboard building experience was assembling a Lily58 kit myself a few years ago.

Pic: My first DIY keyboard, a Lily58 with Zilents and Astrolokeys keycaps. I really like it!

My first DIY keyboard, a Lily58 with Zilents and Astrolokeys keycaps. I really like it!

It’s very cool actually to look at my old soldering work and think about how long it took, compared to my more recent work!

I’m currently running a little Lily58 group buy for some friends, and so far my record is getting a whole Lily PCB (so half the keyboard) from nothing to fully soldered and tested in just a bit over an hour, with no faults to go back and fix.

Design & building process

The keyboard started off very simply. The Lily58 and Reform keyboards are both designed in KiCad, so I just slapped both PCBs into the same file. Then I used the Lily keyswitch positions as a reference for moving around the reform switches. Then I just deleted the unused keys, and all I had to do was reroute all the traces! (Routing an entire keyboard sucks btw, what a pain!)

Pic: My keyboard PCB in KiCad

My keyboard PCB in KiCad

Whilst I was there, I also made sure to use footprints that support Kailh sockets. It seemed a waste to commit myself to a single switch for all time.

From there, I had the keyboard PCB made by OSHPark. They’re an interesting fab; fairly expensive compared to the chinese fabs like JLCPCB, but their quality is really extraordinary.

Pic: This is the keyboard PCB with the hand-drawn keycaps!

This is the keyboard PCB with the hand-drawn keycaps!

Normally I’d only use them for much smaller PCBs that don’t have a lot of dead space, but in this case I splashed out. That ended up paying off; I did a lot of reflow work fixing mistakes on this board, and I’ve had JLCPCB boards start to fall apart in similar circumstances before.

Pic: Test fit of the keyboard in the case

Test fit of the keyboard in the case

The PCB arrived, I soldered everything on and got the firmware working, and all seemed well. Then I fit it into the Reform case and discovered an issue: the regular reform keyboard has big holes in the sides! As in… there’s nothing stopping something from falling down into the keyboard, and then off the side onto your actual motherboard, batteries, etc.

Pic: You can see the gap here. This is why I made a frame!

You can see the gap here. This is why I made a frame!

With the standard Reform keyboard, they get away with this by having the keycaps sit almost flush with the bezel, so that you can’t even really see down the side. Because my layout wasn’t the same, I didn’t have that luxury.

So from there I fired up Fusion 360 and got to work on some kind of frame design.

Pic: The frame in Fusion 360

The frame in Fusion 360

I also whipped up a switch plate whilst I was there, since I’d noticed a bit of flex in the middle of the keyboard PCB (it unfortunately has no support in the middle).

Pic: The switch plate in Fusion 360

The switch plate in Fusion 360

After a bunch of iterating, I finally got to the point where I was confident enough to get the design made in CNC aluminium. This was scary and expensive, but I am absolutely floored with how it came out. It could not be more perfect.

Pic: The frame!!!! Look at that fit!!!!!

The frame!!!! Look at that fit!!!!!

Next step in my project is keycaps! I originally used MBK keycaps with hand-drawn dye sub legends. I didn’t like how this looked, or felt! I ended up tracking down the STLs for the early samples of the LDSA keycaps [low-pro DSA, coming soon – Ed.] currently being worked on, and got them printed in MJF PA-10 Nylon. Once they’ve arrived, I’ll be trying out waterslide decals as a neater way of adding legends. Fingers crossed it works out!!


I have a fork in the MNT gitlab instance here:

It includes both my redesigned keyboard, and my motherboard with USB-PD. If folks want to build it themselves then we should chat first though, since there’s a couple of design issues that might be worth fixing!

1800-ish wooden ortho

An 1800-style ortho board by MetaWhirledPeas, hand made from a solid piece of poplar from Home Depot.

Many of you are familiar with the classic 1800 layout (the inverted T arrow cluster crammed between the alphas and numpad), however, I wasn't sure how an ortholinear 1800 looks like. Nevertheless, MetaWhirledPeas called his board an 1800 ortho, and who am I to disagree?

I've been an avid ortho 40% user for a while now, but I wanted to explore some new form factors – MetaWhirledPeas.

This ortho 1800 (gallery) addresses two concerns:

  • It provides discrete keys for most actions, for when layers are not desired (pressing a mission-critical function key, for instance)
  • It provides a bridge between the ortho 40% and staggered full-size worlds.

It would hypothetically be a good choice for someone wanting to dabble with ortho form factors but not wanting to commit to going crazy with layers. There are only a handful of keys hidden behind layers (function+shift to engage caps lock, for instance).


The author still has all the layer bindings available for use as an ortho 40% board, and he continues to use them a lot. But there are times when he just wants to reach over and use the numpad (data entry, for instance) and "it's nice to do that without fuss".

One of the biggest challenges with this form factor was the keycaps:

I wanted properly labeled keys, so choice was severely limited. I was happy to find this Apple homage set on Amazon with plenty of oddball keys including a 3u spacebar. Domikey sets also work, with a few minor compromises.

Since I was interested in the actual woodworking process, I reached out to MetaWhirledPeas to ask for more info. He was kind enough to shed some light on his workflow so let's pass the mic to him:

The workflow

"My process was a series of underestimations. Between the woodworking and wiring it was significantly costlier than expected, in terms of both time and money. I learned some lessons and made some compromises, but in the end it was a good, fun experience.

I had the layout defined in KLE for months before starting. I knew keycaps would be a struggle, so I formed the layout around the most flexible SA set I could find, a Domikey WoB set. More recently I found an even more flexible Apple-themed XDA set from Amazon. I bought both sets but I've settled on using the Apples.

I had a pretty good idea of how I wanted to make the board. I knew I wanted to make a high-profile case out of solid wood, paired with a steel plate. I was going to need a hand router (cha-ching) and a litany of smaller woodworking tools that I lacked (cha-ching). After a few weeks (months?) of accumulation time I had enough gear to get started. Before I did any woodworking I used to generate a plate from the KLE layout, then ordered a plate through Send Cut Send.

Pic: Poplar case with a steel plate

Poplar case with a steel plate

The original plan for the case was to sandwich two boards together, but I was never able to work out the logistics of it. My only affordable choice for wood was a slab of poplar from Home Depot, which came in predefined widths and thicknesses.

I didn't own a planer, so I wouldn't be able to properly glue two boards together for added thickness. I ended up using the thickest piece of poplar I could find, and used a thin piece of poplar as the bottom cover. Just cutting the board square was a challenge. I used a router bit to do it; maybe there are better ways.

Routing went like this: first I used a roundover bit to create the bull nose on the front of the board. I wasn't sure how this would turn out, so I made sure to do it first before getting too far into the weeds. I then hollowed out the bottom of the board by plunge-cutting with a downward spiral router bit, making the void just big enough to fit the plate.

Pic: A better look at how the plate sits against the keyboard + USB port

A better look at how the plate sits against the keyboard + USB port

Then I flipped the board over and plunge-cut the key voids. The router bit is round, so filing all the void corners was necessary. At this point I used glued wood strips to hold the plate in place, then all that was left was the bottom cover.

Eventually I got it all put together, at which point I used a hemispherical router bit to cut the pen groove, and did one final (nerve-wracking) cut for the USB port. All that was left after that was a little bit of sanding and finishing. I used about a dozen coats of polyurethane finish from a spray can, smoothed over with some 3M abrasive pads.

Pic: Wiring with clumsy (but effective) glued wood strips securing the plate

Wiring with clumsy (but effective) glued wood strips securing the plate

The wiring was a pain. Just slow and tedious. I was advised hand-wiring would be easier than a custom PCB but I'm not so sure. Maybe one day I'll find out what PCB creation is like. When I neared the end of the wiring process I realized my Pro Micro didn't have enough pins to support my layout, so I had to order an Elite-C from Keebio to replace it. All of this baaarely fit within the enclosure, but it did fit!"


  • I should have put more padding on the plate and maybe included screw holes. I went with magnets partly because I wanted to use magnets, and partly because I didn't want to drill screw holes. Drilling holes in the poplar bottom cover was not practical because the ones Home Depot sells are barely bigger than the opening.
  • I should have used a router template. I used an edge guide which was awesome, but it made it difficult to make the cuts as precise as I wanted them to be. I'm not sure how I'd make the template though, since it requires its own precision. Maybe laser cut. - Wood may have been a mistake overall. I might go with 3D printing or stacked acrylic next time.

Most-used equipment

  • Flush cutters. Cheap and multi-purpose. I used these constantly.
  • Hand router. I can't imagine using a jigsaw or chisel for all this. I recommend a downward spiral cut bit for the safest and cleanest plunge cuts and planed edges.
  • Clamps. Buy a set of clamps from Amazon. You need clamps for woodworking!
  • Soldering iron. I tried and failed to get it done with a cheap Radio Shack iron. Had to replace it with a $50 Xtronic. Watch some videos on keeping your tip tinned. So vital! Also, I like tip-tinner for this.
  • 1/16" weather stripping from Amazon. So useful! Works great as rubber feet too.


Leeloo, a split keyboard resembling the Lily58 – with a twist!

While the design was inspired by the popular split keyboards Lily58 and Corne, Leeloo is a split designed and built from the ground up with a twist – rotary encoders.

Clickety Split designed this split with 6x4 keys and rotary encoders in 6 optional positions.

Albeit, there is no doubt where Leeloo's heritage is derived from – Lily58, and Corne – it is not a copy-paste-modify implementation. It's perhaps the finer details that separates Leeloo from its predecessors – Clickety Split.


  • Support for MX/Box or low-profile Choc switches*
  • 90% of the switches are socketed (except the rotary encoder positions) – 6 positions require soldering.
  • Optional 128x32 OLED displays.
  • Option to select one of three positions for an EC11 rotary encoder on each half.
  • +/- Battery pads for wireless implementations.
  • Support for a micro on/off switch for travel.

(*At the moment there are two PCBs available: v1.0 and v1.13. Both PCBs support Choc switches but only v1.13 works with MX/Box switches – allegedly due to a footprint error.)

To learn more about the origins of Leeloo, read this blog post: Leeloo – The Series’ Genesis. It pretty much sums up how an ergo board should be designed: try some existing models, identify their problems, define your preferences, print and try paper mock-ups, iterate, etc. – i.e. cycles of observation, design, and testing.

Actually, the design and manufacturing process is documented quite well in their blog.

Albeit the write-up linked above refers to Leeloo Micro, a 5x3 version with Choc spacing, the first Leeloo marketed has 6x4 keys and the classic 19.05mm spacing.

Leeloo will have three different form-factors that will carry the same 5 modifier keys, yet a different matrix for 6x4, 6x3, or 5x3. There will also be LED versions for individuals who wish to have per-switch underglow.

Peanut Matcha Jade

A 5x6 Dactyl Manuform variation by Mike Pisman – with 5 thumb keys and smooth edges.

A 5x6 Dactyl Manuform variation by Mike Pisman aka mpisman – with 5 thumb keys and smooth edges.

This is my first Dactyl Manuform keyboard. I made a variation of Dactyl 5x6 with 5 keys for thumb cluster. I wanted to smooth out edges of the keyboard and that's what came out – mpisman.

STL files and more photos available on GitHub:

  • Print parameters: 0.12 mm layer height and Polly Terra PLA filament.
  • Logical layout: Halmak with minor modifications.
  • Keycaps: PBT ZDA Match.

Workflow of smoothing out the edges:

I used some generator to get an step file, I think it was this one, then edited it using Shapr3Dmpisman.

Lolcatz's Blank Slate

Lolcatz52 designed and printed an ergo split to fit his own fingers.

Daily handwired project: Lolcatz52's Blank Slate, a wireless ergo split.

This is a handwired 36 key split, with a column stagger that fits my own fingers pretty much perfectly. 20g gChoc switches, using 2 nice!nano v2's and ZMK with a 2500mAh battery (went a little overkill there lol) – Lolcatz52.

In addition, the case has magnets (6x1mm neodymium magnets) so it's easier to carry around, and it also has rubber feet to sit nicely without moving on the desk.

u/Lolcatz52 designed and 3D printed the case and plate himself, STL files are available here:

It's got a bit of a learning curve due to keys being choc spaced instead of MX spaced like I'm used to, and less keys so I have to learn new layers for everything, and I'm also learning the colemak q;ix layout at the same time, so its a lot, but not too bad so far.

More photos:

PICO Chord keyboard

A well-documented chorded keyboard project based on the Raspberry Pi Pico: the PICO Chord.

I'm not sure about the designer of this keyboard. The author of this write-up, introducing the Pico Chord, is Ben Everard (and there is no reference or indication of other authors). However, the owner of the Git repo and the demonstration video is Rob Miles.

Whatever, here is the repo:

The keyboard is based on the Cykey chord design by Cy Enfield which was used as the basis of the Microwriter and Microwriter AgendA devices developed by him and Chris Rainey in the '80s.

Here is a quick demonstration:

As Tim Rowledge points out in the comments, there is a more promising case design here – another project inspired by the Microwriter.


Gondolindrim interview

Revered Brazilian PCB designer Álvaro "Gondolindrim" Volpato interviewed by _IanOfEarth.

I was pretty sure I covered Gondolindrim's Acheron project on but can't find it now. Maybe it was in the very early days when Keyboard Builders' Digest was a mere weekly link collection published as a Reddit post. :D

Anyways, here is the quite lengthy video on the design lifecycle of a PCB, the Joker microcontroller architecture, how the community has changed, etc.


PRK firmware

PRK is a PicoRuby-based keyboard firmware running on RP2040 chips.

Hitoshi Hasumi's PRK is an alternative keyboard firmware for RP2040-based boards, utilizing the PicoRuby language.

To clarify things up: PicoRuby is the Ruby interpreter for one-chip microcontrollers, and PRK firmware is a keyboard firmware framework written in PicoRuby.

Both PicoRuby and the PRK firmware are developed by Hitoshi Hasumi aka @hasumikin who is a programmer, more specifically a cloud architect for web applications, living in Japan.

As noted by Hitoshi, PicoRuby is the preceding project:

Firstly, I've just wanted to make Ruby eligible for one-chip microcontrollers because my job relates to some IoT systems. But at the same time, I remember Matz, the founder of Ruby language, said that it'd be great if Ruby could be used in a DIY-keyboard. (Actually, Matz himself is also a DIY-keyboard lover.) This is the reason that I started the PRK project just after PicoRuby became capable enough – Hitoshi.

I've planned to feature PRK for a long time since it was used on several keyboards introduced on this blog already: e.g. the C-13X by flurples,'s Cool836pico or policium's Grin Type-R, just to name a few.

It's hard not to notice, at least as of writing this, that all the contributors and users are based in Japan so this firmware can be considered to be a project of the Japanese DIY keyboard community.

I mainly tweet in Japanese and actively support those who are having a problem with PRK on Twitter. However, I'd be really glad if people all over the world would use the PRK Firmware. I will support you in English! – Hitoshi.

But that's enough talk about the background, let's see the nitty-gritty details. Here is a video presentation by Hitoshi himself introducing PicoRuby and the PRK firmware with some examples at Rubyconf 2021, Denver:

TMK, QMK, KMK, ZMK, PRK, etc. Why would you need one more keyboard firmware and where can PRK be plotted on the map of all the firmwares with regards to mission, usage and features?


Up until last year, the most famous firmware (de facto standard) was QMK (which started out as a fork of TMK). QMK is written in C, and – many user may not be aware of this but – you write your keymap in C accordingly. Despite all the tools available, the QMK workflow remained a real PITA, especially for real custom keyboards with unique matrices.

No wonder the appearance of Raspberry's RP2040 microcontroller and development boards like the Pi Pico, Adafruit KB2040, Tiny2040, RP2040-Zero, RP2040 Stamp, etc., combined with CircuitPython and KMK was received with acclamation.

PRK is positioned along those lines and, with its target chip being the RP2040, it may be the closest relative and an alternative to KMK. With the main difference being that while KMK/CircuitPython uses Python, PRK/PicoRuby uses Ruby as its programming language to achieve pretty much the same thing.

Other than that, both firmwares execute your program directly on the keyboard without compilation. Changes made to the program are immediately reflected in the keyboard's behavior.

When to choose PRK?

So, at least if you want to delve deeper into custom functions, choosing one firmware over the other comes down to your choice of programming language.

Being familiar with the language is not so important when your keymap consists of only predefined keycodes but it gets more critical if you're up to write some unique functions. After all, with all the power and resources of the RP2040, a single keypress can launch a whole array of programs – as opposed to merely generating a humble alphanumeric character. In this sense, QMK is for masters of C, KMK for Python-heads and PRK for Ruby-wizards.

Some friends of mine said that PRK is better than KMK in terms of response to inputs and they feel comfortable using PRK. Also, I think PRK's just improved farther in that point because it introduced debounce algorithm today. :D If you are annoyed by bouncing switches, please try PRK Firmware – Hitoshi.

Installing PRK

The installation process is the same as with CircuitPython and KMK, which means you're likely done in 2 minutes. All the development boards sporting the RP2040 chip appear like flash drives so flashing the firmware and updating the keymap means simply copying files.

No compilation needed, there's no cumbersome or confusing toolchain involved like with QMK's local building environment.

Btw, here is the Github repo in case you can't wait to try PRK:

Let me include another video of Hitoshi. Although this one is in Japanese, the slides are in English and this one contains more tips:

Features of the PRK firmware

From the feature list, PRK is capable of driving non-splits and symmetrical splits via UART.

It handles macros, RGB LEDs, rotary encoders, etc. And as already mentioned, it introduced debounce algorithms today. Yeah, a new version was released just during writing this piece. See the latest changes here.

Media keys, OLED displays, mouse/trackball and I2C are not yet implemented but some of these are in the main focus of further development.

PRK will introduce VIA feature in the next version. It means you will be able to configure a keymap trough Remap. Then Mediakeys, Mouse/Trackball, and Gamepad are upcoming features – Hatoshi.

I also reached out to @policium (who used PRK on his Grin Type-R) for his opinion. Here is his full impression on the PRK firmware, and here is an apt summary:

PRK is developed by crazy people, so they implement maniacal features before they implement normal features – @policium.

@policium refers here e.g. to duplex matrix support – and no, this is not the duplex matrix we westerners talk about. (More on this in a later post.)


As a summary: PRK is another alternative firmware for keyboards sporting the RP2040 microcontroller. Its interchangeability with KMK makes it easy to test so feel free to give it a try!


ITT ETL18 switch teardown

Chyrosran22 introduces the vintage ITT ETL18 switch with horizontal flappy coil spring.

Thomas, describing himself as a "sucker for interesting and unusual switch designs", covers ITT ETL18, another obscure switch model from the early '80s.

Today we look at another, rather weird switch design - ETL18 switches from ITT. Superficially similar to Mitsumi Miniature mechanical in that it uses a horizontally-slung coil spring to provide tactility, it approaches this tactic in the opposite manner – Chyrosran22

Tips & Tricks

LDSA keycap profile

LDSA is a new Choc-compatible low-pro keycap profile by Darryl from – with deeper dishes.

Darryl, designer of the Corne-ish Zen keyboard, announced his idea of a new keycap profile in January. His plan was essentially a low profile version of the DSA keycap (or uniform MT3): a spherical and uniform profile with deepened scoop and lengthened skirt "as much as possible."

I want to produce something that is comfortable to type on, and looks a bit more traditional – Darryl.

According to Darryl, the dishes on these are deeper than any other commercially available keycap. And the finger pad that your finger touches is larger than that of MT3 and SA.

Pic: LDSA render

LDSA render

Actually, the dishes are close to the deep dish homing keys of MT3 caps: 1.52mm vs 1.63mm.

Not going for a sculpted ergo set makes it easy to put these keycaps on any obscure physical layout.

Despite the deeper dish, LDSA (blue) is not much thicker compared to MBK (red). Otherwise they are identical in width and height so they fit Choc-spaced (17x18mm) PCBs:

Pic: LDSA (blue) vs MBK (red)

LDSA (blue) vs MBK (red)

LDSA seems much larger because the skirt is 1.35mm longer. Definitely taller by a little bit, but probably only like half a mm – Darryl.

The molds and the first sample caps are ready, so after the initial renders there are already real comparison photos available, e.g. this one with a lonely MBK lost in the sea of freshly arrived LDSAs (click to enlarge):

Pic: LDSA vs MBK


How to grab those? Stay tuned for the upcoming presale which is slated to start April 24. They will be available at and can be shipped internationally. Edit: Here you go.

Doing a little presale in a week or two for cheap to get the profile out there and see if people like it enough to go dual shot – Darryl.

Until then, here are some STLs if you want to print the caps and see if you like this profile. License reminder: these files are released under the Creative Commons, non-commercial license.


One last photo with gorgeous black LDSA caps:

Pic: LDSA in black

LDSA in black


  • They will be available in all black or all white PBT
  • They are choc sized (17x18mm)
  • They are a deep scoop keycap, similar in feel to the MT3 and SA homing dishes
  • They have a longer skirt to hide the switches more (compared to MBK and MCC)
  • They have slightly longer legs to allow for o-ring use and still allowing firm grip on the stem (compared to MBK and MCC)


SmartKnob is an open-source input device with software-configurable endstops and virtual detents – designed by Scott Bezek.

A brushless gimbal motor is paired with a magnetic encoder to provide closed-loop torque feedback control, making it possible to dynamically create and adjust the feel of detents and endstops.

Internally, everything is powered by an ESP32, with a TMC6300 BLDC motor driver, HX711 strain gauge ADC, VEML7700 ambient light sensor, and more! – Scott Bezek.

Check out this demo:

Since you can't feel the detents through the video, Scott suggests you to turn up the volume so you can at least hear them, particularly the fine-grained detents toward the end of the video.

The best thing? It's open-source/open/hardware:

Keyboard Spotting

Fairlight MFX3 Plus

The Fairlight MFX3 Plus is a dedicated hardware designed to handle 24 tracks of recording live.

Some people like dedicated hardware over using a general purpose computer, and we keyboard enthusiast owe a big thanks to them (from CNC to ultrasonic machine operators) and the designers and manufacturers serving them.

Posted by @rzwv, the Fairlight MFX3 Plus sports ALPS SKCL Yellow keyswitches, and was designed to handle 24 tracks of recording live.

In essence, the MFX3 is the hard-disk replacement for a conventional analog/digital multitrack transport – up to 24 tracks of simultaneous, real-time record/replay locked to timecode, with all of the normal editing functions.

According to Mel Lambert reviewing the MFX3 in this article, one neat aspect of this beast is that the removable 5.25-inch MO drive can not only hold a complete 24-track project, but will also replay up to 12 tracks continuously.

Without menus, mostly depending on keyboard shortcuts, this type of system requires that you don't walk away for too long. Otherwise you will forget how to run this – techristian.

Fairlight MFX3 Plus keyboard layout (click to enlarge):


Siemens Unity 2

A pimped-up Siemens Unity 2 "Super Silent Keyboard" posted by catsontuesday.

Fellow Redditor catsontuesday found a gorgeous Siemens keyboard with missing keys, but the challenge didn't frighten him.

The Siemens Unity 2 is allegedly a rare GMK board with GMK caps and MX Black switches. Full NKRO (diodes on every switch) and PS2/USB connectors.

It has a rubber sheet over the switches that make the keys feel HIDEOUSLY spongy but very quiet as well – catsontuesday.

This is a device for an audiometry machine (the metal knobs are audio seekers to be used in the Siemens software) so proper soundproofing makes sense.

More pictures about a similar model with photos of the rubber membrane in this DT thread.

That was Issue #74. Thanks for stopping by.

This issue was made possible by the donations of:, MoErgo Glove80, u/chad3814, Aiksplace, @kaleid1990, @keebio, Timo,, cdc, Sean Grady, kiyejoco, Bob Cotton, FFKeebs, Richard Sutherland, @therick0996, Joel Simpson, Nuno Leitano, KEEBD, Spencer Blackwood, Yuan Liu, Lev Popov, Christian Mladenov, Davidjohn Gerena, Alexey Alekhin, Fabian Suceveanu

Your support is crucial to help this project to survive.

Discussion over at r/mk!