I made a split, even posted it here on c/emk, but at this point I am just too old, yes, too old to begin the training. I had no motivation to actually learn to type on the thing, but rather just wanted to make more keyboards.

This is the first one I’ve seen that made me (briefly) reconsider. Nice work!

Do I see fuzzy skin on the plate at least?

So I’m not using it much, because as it turns out I may like tinkering and making more than I like typing practice. My parallel project was an ultra-budget mod (like sub $50 total) of the cheapest hotswap 1800 I could find.

So that said, the upper thumbs (or lower indexes, as you say, LOL) are definitely not as convenient, but also not problematic with careful key mapping. Currently they have the arrow keys (with the other four nav keys on the second layer), the layer toggle, and the delete (as opposed to backspace). none of those should be particularly necessary for “proper” typing. Then, like I said, if it doesn’t quite come together, there are plenty of keys to spare if I wanted to cover over some of them with POS keycaps and then remap. KMK is the real rockstar here. hold down escape while plugging it in and it turns into a flash drive with one relevant python file to edit.

Cross posting the writeup comment as well:

…wherein I endeavor to combine as many highly-questionable design, material, and build decisions as possible, while still ending at a usable keyboard.

• 4x14 matrix, ortho layout, and with a quick change in keymapping it could support an aggressive 1u pinky stagger. Frankly, that’s what I designed to to explore but… eh, maybe later. Similarly, a few POS keycaps could tweak the thumb cluster at the cost of a couple of keys (there are plenty to spare, LOL).
• RP2040-Zero clone running KMK firmware. I haven’t tried QMK, but like KMK a lot.
• One additional layer that remaps most of the keys.
• Hand-wired using lots of stuff, but mostly the diode legs and stranded wire from an old patch cable. We will not talk about the cold joints (seemingly none of any structural significance though) or the burnt-rosin mess that is hiding under the MCU.
• 3D printed plates and cases. Skeletonized bottom case because it was gonna take like an extra 12 hours to print each one otherwise. Ain’t nobody got time for that. Besides, I can revisit the wiring gore at any time now. For bonus points, zoom in to to see where I had bed leveling issues and figure out which of the four prints came when I started a new roll of white PLA from a different brand. 100% infill because solid plastic is best when you may have to enlarge holes, drill new ones, and generally coax a print into the shape you subsequently discover you needed all along.
• One failed experiment with using HDMI to link the sides. Eventually got all the rows and columns onto working pins, but there were ghost presses that got worse or better depending on the cord I used. Eventually just ripped it out and strung a hard line of spliced wires and heatshrink, with hot glue strain relief in holes that were intended to be covered by electronics and cable ties to hold 'em down. On the plus side, losing the large-ish HDMI breakout boards meant the tiny little Zero could fit under the case instead of up top. If there’s a next time, I’ll use two MCUs and a TRRS like a normal weirdo.
• Outemu Browns salvaged from a Filco-knockoff 104-key gamer board I used to use for work. I still love me some cheap boards, but I share an office with a nine year old, and she can deal with my clicky obsession on other boards (those other two are Box Navy and Outemu Dustproof Green, respectively).
• Literally the cheapest full set of uniform-height keys with legends, plus a few spares from some clone sets I already had. The white keys are from a $9.99 set of XDA keycaps that is about 70% staid and clean, and about 30% kawaii shiba inus. The aforementioned 9 year old likes those.
• Rubber feet from Daiso. Kinda slick. Might change them later.
• Mismatched screws because this fucker was gonna be done TODAY; no more shopping.

Somehow, the thing works perfectly.

The Good+Cheap pair from the “pick two” cliche gets overlooked. :-)

Beautiful work, btw. The people who want it will REALLY want it.