Keyboard Builders' Digest / Advent Calendar
Ripping the wires out of relics
Krikun98 designs 44-key wireless splits with weird switches collectors would either tear him apart for or would be very intrigued by.
Published December 16, 2022
My name is Alexander, I am a software engineer and I like wireless splits. I used to live in Russia, and for the last two years, I did not have much of an income. On top of that, I like unusual switches.
You would not think it based on the state of my collection, but my first mechanical keyboard was a full size – a Ducky Shine 7. After using it for a while, I started thinking I might enjoy something more refined and joined my first group buy. In the meantime, I got a switch tester.
Initially, I never thought about using a split regularly – it was cheap and did not need a lot of switches. However, when the lockdowns hit, I did not have a chance to grab my new full size from the office, and I had a bachelor's thesis to write. By the end of it I sold the full size and was questioning the group buy.
Wires have always bugged me, though. Portability is key with a split, and dragging a bunch of cables around every time I moved was a major annoyance. So, as soon as nice!nanos were available, I jumped at the chance.
nice!nanos, however, are not cheap, especially if you factor in shipping to Russia. I wanted to try a lot of switches. Luckily, Joric – a member of my local community and a titan of the wireless split community – has developed an open source controller you could build yourself: the nrfmicro. I was afraid of destroying it, but I had to try – my wallet could not handle the amount of nice!nanos I knew I would need.
Soon after, I developed a few more annoyances with my wireless splits. The inability to turn them off made transportation or disassembly a pain. Reset buttons were annoying to reach for. LEDs were outright useless. All in all, I decided that while drop-in controller replacements are nice, a board tailor-made for wireless would significantly enhance the experience.
Sporne
Early Corne power switch mods involved soldering a power switch to the TRRS jack contacts in a way that wasn't easy to do correctly (you can see an example in the next section). So, my first wireless-focused PCB was a version of the Jorne 3.0. I added dedicated power switches and battery contacts. The power switch placement was inspired by the Rollow, and it proved to be quite comfortable and compatible with nearly all existing Corne/Jorne cases (cough, Aurora Corne, cough).
A while later, a warehouse with 2,000 NMB keyboards with Hi-Tek 725 switches was found in Germany. Space Invaders were rare before this occasion, and although a few custom PCBs existed, there were no split designs – especially not wireless ones.
I do not want to specifically say how many of those keyboards I have procured, but let's just say I have built a round of Sporne prototypes and a bag of switches is still lying around. I picked red from SI designs that a few friends created, got my sister to draw up a logo and decided to go with 3D printed cases. I also designed custom controllers and patterns for the plates. I'd say the prototypes turned out quite fun, and I use mine often.
Although some enthusiasts say 4th generation Hi-Tek 725 switches are not as great as the one-eyed linears of old, I still love my board. While not as smooth as some modern MX-style switches, they've got… character. Also, the homing keys on NMB DEC boards are a unique style – instead of dots or bars they're just spherical caps on an otherwise cylindrical profile.
An interesting issue with ripping these rare boards apart for splits is keycap availability. While you could get enough switches for two splits from a single RT-101 keyboard, you've only got one set of alphas. That's why 3D printing keycaps is so awesome, and parametric profile generation (found in projects by Pseudoku, Shoggot, Riskable and matt3o) is even more promising.
If anyone's interested in creating a model of Space Invader sliders/keycaps to add to a generator – please drop me a line. I tried to make it happen last year, but other events kinda took over my life…
The near-final version of the Sporne can be found here. It supports MX/Alps/Hi-Tek 725 switches. Plates for Space Invaders can be found here for laser-cutting and here for PCB production.
Nijuni
You might be wondering what's up with the weird pinky "ear" by this point. Well, this was an idea started by the Jian – the 44 keys are supposed to fit a layout better suited to Cyrillic and have all the programming brackets accessible without layers. Although there are ways to fit the Jian's layout into a 42-key board, I've gotten used to it and tend to include it on all my boards. However, it can be broken off if you don't like it.
The Nijuni is a board that combines the Jian's stagger and pinky with the Corne's thumb cluster and controller placement. It's also wireless-focused from the get-go – power switches, no LEDs, hotswap/solder footprints and the like.
The currently published version 0.2 of the Nijuni is compatible with MX or Alps switches. However, I do have some plans to expand that list. I'm even working on a Hall Effect version for Zbrojovka 262.3 switches and sensors.
PCBs have a minimum order quantity of five, while some rare keyboards can only supply enough switches or caps for a single split. Furthermore, some PCB fabs take issue with the plates, demanding additional payment for "many rectangular holes". Therefore, I've taken to ordering a bunch of PCBs and sourcing plates locally. A common material available at nearly any laser cutting shop is engraving laminate – the material number tags are commonly made of. You can find it in 1.5 mm, the perfect thickness for MX plates. It's flexible, sturdy enough (although I'd avoid especially thin spots) and can be engraved.
However, the whole reason we're here is to get away from MX. Interesting switches tend to require 1.2 mm plates. That can be an issue: other than FR4, it's hard to find 1.2 sheet material locally. However, I've found that 1 mm PET (or PETG) can work well for Alps, various clones and Chocs, if the footprints are tight enough.
Space Invaders are a different story – as far as I'm aware, the original plates are 1.4 mm, so FR4 is pretty much the only option here. Although my Sporne is fine with a 1.2 mm plate, 1 mm plastic was too loose for comfort for switches with no positioning pins.
When working with a laser cutter, it's important to remember that every machine has its specific tolerances. Since plate footprints need to be as tight as possible, I would recommend cutting test plates with holes at 0.05 mm size increments in your preferred materials before committing to a larger order. Test plates for MX, Alps, Omron B3G-S and Hi-Tek 725 can be found here.
Skean
Custom PCBs for custom controllers are all well and good, but at some point you just see a Corne-ish Zen and think to yourself "if I'm making custom PCBs and controllers anyway, why not combine them?"
The Jian served as another inspiration – I don't really like screens, and while having the controller exposed can be an aesthetic all in itself, the empty space just oozes style. After seeing a friend of mine try a similar design with the Chocofi and shifting some parts around, I've discovered the Nijuni's thumb cluster can fit the same E73 module the nrfmmicro uses. Throw in some ESD protection, pepper it with some funky battery placement ideas and chuck it all in an auto-router and voila! This is how Skean's V0.1 was born.
The most important lesson this board taught me was not to verify PCB designs at four in the morning right before sending them to the fab.
I accidentally assigned a row and a column to the same pin.
And then got 17 PCBs made before noticing the error.
Nevertheless, some creative cutting and wirework allowed me to salvage the prototypes. They turned out to work fine and were quite comfortable. I can especially recommend the reset/power switch placement. While ZMK has been rock solid for a while, having an easily accessible reset is still nice, and these can be pressed with your thumbs without ever moving the board.
A small downside of the prototypes was their thickness. The Skean was originally meant to use 233350 batteries under the PCB. Typical MX switches have a protruding center post of about 3.3 mm at the bottom. Kailh BOX switches are a bit better at this with a post of 1.2 mm, but I like 0.8 mm PCBs, so they wouldn't work either.
Alps, however, have no posts. And Gateron's CAP switches only use the posts for positioning – they can be cut right off. The Skean's design was finalized right before Zeal came out with their new high-end CAP switches, and you wouldn't believe how happy I was.
So, you have your bag of Gateron CAP Yellows, you mangled the posts and you have 0.8 PCBs… Theoretically, 3.5 mm from the bottom of the plate to the top of the PCB plus 0.8 mm of the PCB plus 2.3 mm of the battery should fit within 7 mm standoffs. However, the batteries turned out to be closer to 3.5 mm, and some of the PCBs I had were 1.6 (AllPCB didn't allow 0.8 for their free PCB promos), so I had to build the protos with 8 or 9 mm standoffs. That's not too shabby – a typical Corne is about as thick, and the battery is three times the capacity, but I knew I could do better.
You see, a typical battery is 3.5 mm thick, and that just happens to be the same as the space between the PCB and the plate on an MX keyboard… That got me thinking. I discovered I could shove a typical 301230 in between the plate and the PCB, and one of the mounting holes could be used to feed the battery wires through. With a few more tweaks and fixes I published the Skean V0.2.
What I would like to highlight here is the importance of automation. The Skean is a board with quite a few configuration options – pinky or not, switches, plates for PCB production and laser-cutting and all that jazz. Re-generating all your PCB images, gerbers and other artifacts and keeping them up-to-date can be as time-consuming as the actual design work, and as a software engineer I just had to automate as much of it as I could. I was inspired by Soundmonster's Samoklava project, but I have learned not to trust auto-routers, so I focused my efforts on everything after the actual PCB design process.
My current system uses kikit and Docker to build PCB images, gerbers and laser-cutting files either in Github Actions or with a single script. The Github repository is also set up so that the readme automatically picks up the latest PCB images and production files – a casual user does not even have to touch the actions tab. This system is used (with minimal changes) across all three of my currently available project repositories – the Skean, the Nijuni and the Jorian840. I think it is a nice way to decrease busywork and maintain a nice repository layout.
There is, however, still plenty of work to do. Swapping footprints to automatically generate plate files for all supported switches is the easier part, but I am also working on a way to automatically generate 6-column (Corne) and 5-column (Minidox) versions of PCBs and other parts from one main source.
Once these ideas are implemented, the system will probably be released as a Github template. If you have any ideas or can give some pointers on generating 3D-printable cases – you're more than welcome to find me on the Absolem server.
The Skean can be found here, it supports MX or Alps switches. A hotswap version is currently in a beta branch, test units are in production. I've also got a few SKCC-shaped ideas for the next version and I'm always on the lookout for thinner batteries.
Jorian840
I've mentioned free PCB promotions a couple times here. They were a huge hit in the Russian split design community – an opportunity to test out a new design you have been sitting on without shelling out for the shipping. When NextPCB announced a promo for 10 free 10*10 PCBs, I was a bit sad – a conventional split PCB is about three to five centimeters wider. And then I remembered this:
The original Jorian is a semi-working version of the Mitosis that follows the Jian's layout. The PCB can be used as a plate if so desired, it supports multiple switch types and sports RGB out the wazoo. It also needs a dongle and you have to use an ST-Link to modify the firmware. It was a wireless split from an era before wireless splits.
The Skean, while nice, still included some baggage from its Nijuni origins. The E73 module does not have enough topside pins to support 22 keys, so it is still using a matrix. It also has an expensive ESD protection chip and some additional power filtering circuitry. What if we were to toss all of that? After that, why not include the Jorian's option to use non-rechargeable coin cells to toss the charging circuitry?
Well, we would get a wireless split that costs (as of January, 2022) $26 in materials for two fully built PCBs and case hardware, including shipping. If you can find some Alps clones (wax can do wonders to these), get a PET plate/case made (which is usually dirt cheap) and do some soldering, you can get a fully featured ZMK split for nearly the price of a single nice!nano.
Of course, you could solder that charger on, spring for some nice switches and 302025 rechargeable batteries (same idea as the Skean, they go between the plate and the PCB) and get a thin wireless Jian-like. The useless square above the module/battery could house an engraving.
The Jorian840 still supports 233350 batteries under the PCB. It can also be built in 42/40/36/34 key configurations or used as is in the original 10*10 shape. It can be found here. It supports MX, Alps or Omron B3G-S (or KPT) switches.
A hotswap version is currently in a beta branch. I'm also working on a Jiran BLE-inspired 18500 or 14500 version, but I need to figure out how to include overdischarge protection on the PCB.
I'm working on supporting more switches, although that is a bit more difficult on the integrated designs. Due to the USB port placement, some switches that cannot be rotated (Space Invaders) or have pins all over the place (Futaba MA) can be difficult to place or route, but I am working on a few solutions – the 14500 version would alleviate these concerns, for example.
Wrap-up
As you have probably gathered from all the previous sections, I have a lot of plans. And they're not just plans – I have literal piles of vintage switches sitting in a box and an SLA printer on the way. I've also got a few more software-oriented projects in the works – I have to finish ZMK mouse emulation someday (I literally got my current job because of it) and I'd like to get capacitive, optical and Hall Effect switches working with ZMK. If any of the ideas I have mentioned sound interesting or you have some of your own – please reach out!
I would also like to shout out a few projects I helped out with – I already mentioned the Jiran BLE Lite, and the unibody TK44 has already been featured on kbd.news, but you should also check out the Dao and the wEnki44 – awesome Choc boards for those of you who found my stuff a little tall for your liking.
---
If you have been following the links to my repositories, you may notice most of them have not really been touched after February of this year. I'm pretty sure you can guess the reason.
This hobby was a big component of getting me through it all. Desoldering NMB boards distracted me in the first few days, friends and meetups kept me sane, and selling prototypes helped ensure I had enough resources to leave my home country behind. However, I do not feel like it is my place to speak about the atrocity Russia is committing.
Ukraine has a vibrant mechanical keyboard scene, and before the war it was pretty intertwined with the Russian community. I got my first Blue Alps there, my first group buy was a trainwreck inexorably connected to a CNC shop in Ternopil, and I got my first set of Chicago Deep Dish keycaps made at an MJF shop in Lviv. I made a good number of friends through the hobby.
A few days in, some of them were talking about unexploded rockets stuck in the pavement outside their windows.
I hope they get through this.
I hope they win.
I hope those responsible face trial.
| Alexander Krikun (24)krikun98 |
|---|---|
| Location | Yerevan, Armenia |
| Description | The guy who fills a whole table at a meetup with weird splits |
| Occupation | Software Engineer |
| Joined | 2019 |
| Niche | Wireless 44-key splits with unusual switches |
| Fav. switch | Alps SKCM Orange, Zbrojovka 262.3 Hall Effects |
| Fav. profile | DCJS, CDD, MT3 |
| Other hobbies | climbing, mountaineering, ukulele, knives |
| Links | https://github.com/krikun98 |
Published on Fri 16th Dec 2022. Featured in KBD #107.
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