I've been thinking about making a new keyboard that's somewhere in between my first split ergo keyboard and my grid60. So a split (but not separated) ergonomic keyboard with staggered columns.

Basically like an Atreus, but with a few more thumb-specific buttons and 60 keys total.

In terms of the construction I'm thinking of doing more fancy stuff with the sound - so actually have a plate for this one. Foam between plate and PCB, and silicone below. Maybe a gasket-mounted plate?

This is roughly what I'm thinking for (half of) the layout. It's a little weird-looking but I quite like it.

I think I can manage to make it so that you flip the left side PCB over to make the right half. If I can get my head around it, that is.

I'm gradually getting there with my split keyboard layout. I can tell that getting everything to the connector is going to be tricky! Tonight I'm dealing with the battery/power stuff in the top left.

It's starting to be less of a mess... or at least, a more compressed mess. Power stuff is mostly done, just got to connect everything to the microcontroller module and the keyboard half connector.

Getting there with the keyboard routing, but it's getting pretty messy. I think I'll need to redraw most of the tracks to tidy it up and rearrange stuff.

Mostly done with the keyboard PCB - it's still a bit messy around the microcontroller, but I can live with that.

Oh, just realised I need to remove the ground fill under the antenna!

Aaand I think that's the layout done! I need to review it (particularly how the connector between the two halves works) but I think that's pretty good!

Good thing I checked the connector - it doesn't work out quite how I thought in my head! I thought flipping one PCB over and putting the header on the bottom instead of the top would connect pin 1 to pin 2 and vice versa.

But this paper mockup shows that pin 1 is gonna connect to pin 1, because both the PCB and the connector have been flipped so they cancel out.

It's not quite back to the drawing board - I'm pretty sure I can do my original plan which was to have the connector straddling the edge of the board. That way the connector orientation *does* flip with the board, so the pins do get swapped!

I think it's ready! I changed the connector over to an edge mounted one (which may or may not be very resilient to stress). Also took the chance to move the mounting hole close to the USB port, to hopefully strengthen that corner of the PCB.

Started designing the plate for the Schism keyboard. It's probably not necessary but I'm planning to gasket mount this, and generally do stuff to make the keyboard sound nice!

I'm getting somewhat used to the way of doing things, switching between workbenches as appropriate (e.g. designing features in PartDesign, making arrays in Draft and doing boolean operations in Part.

I think it could be nice to have some of these features duplicated in other workbenches (e.g. PartDesign could do with having Draft's array tools). I'm sure there's some reason they're not, though.

I think I've settled on how to mount the Schism plate. I've added nubs around the perimeter of the plate with a notch on either side, and then you hook O-rings into those notches. That lets me tweak material and thickness of the gasket by getting different O-rings.

My Schism keyboard PCBs have arrived! Unfortunately I have a busy weekend so probably won't be able to assemble one for a few days :(

I put the power/battery stuff on one Schism PCB and the voltage regulator was getting hot. I wonder why...

... oh that'd do it (schematic symbol has different pin order to actual part because I copied without checking)

Managed to compile Adafruit's bootloader (gitlab.com/gbrnt/schism-bootlo) and the keyboard actually shows up in dmesg, as a USB drive and the LED pulses!

Next I need to add the board to Zephyr.

Haven't posted any progress on my Schism here recently, so here we go:

I've populated both sides of the keyboard now (right side still has no microcontroller yet, just using it as an extension of the left side's matrix).


The OLED worked immediately once I copied some config stuff from another ZMK keyboard. Generally after a minimal bit of figuring stuff out, ZMK has just worked.

The case design is still in progress, but the plate is relatively complete so I printed a couple and installed them. This is where I found that my printer was scaling things up by 0.75%.

It's actually usable now - I used it all day today!

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I'm now back home and working on the Schism keyboard again. This time on the case design.

The plate gets sandwiched between top and bottom halves, with o-rings surrounding the plate. I've added a small chamfer on top and a large chamfer on the bottom of the case, to make it look a bit thinner.

I've printed the Schism case design and it pretty much works! It turns out I didn't really think about where to put the battery though. Probably just needs a slight indent added so that there's enough space underneath.

I've lubed all the Gateron yellow switches, and it sounds really nice! Needs some sound damping foam underneath, and I still need to print the other half of the case.

I finally designed the right side of the Schism ! Because the PCB flips over it's not just a mirroring - most features need to be mirrored, but some need to be added for only left or only right.

The module for the right half of the Schism arrived, so once I sort out the firmware I can use it split in half!

I spent most of today struggling with ZMK configuration trying to get the two halves to connect. Now it's way past my bedtime and I just realised that the right half was looking in the wrong half of the matrix, where there are no keys >:(

Now it still doesn't work, but it's at least detecting that keys are pressed!

But it does raise the question of whether one of my previous attempts was actually working other than looking in the wrong places for the keys.

Schism works! I haven't yet added the batteries (and need to disassemble the board to mount them) but it's working wirelessly and split in half!

I suspect it now *won't* work when joined back together, but that's a problem for another day.

I tried out designing a keycap for Schism that's a little bit flatter, and halfway between XDA and a chiclet key. I think it looks nice but I'll need to print more before I can really make any decisions.

The print orientation isn't ideal - the layers become very visible because of the shallow curve of the top surface. Now I've sorted out the supports a bit better (gone for complete overkill) I can try tilting the cap a little when printing.

Some more keycap testing for the Schism - The rounded one was the first one, then I went for a squarer design, now I'm trying out a third design with a flat spot in the middle instead of a gently curved top.

I like the look of these new ones, but I haven't yet printed enough to tell whether I like the feel.

@fortifieduniverse Thanks! This might not be its final form but it's a good start. I'll be testing out some different sound-shaping options like foams.

@gbrnt Oh, I know all about "might not be the final form"... 👍 Always enjoy watching your progress!

@gbrnt @normandc @fortifieduniverse Yeah! It looks very nice! Wondering if I'm going to build a custom #keyboard myself at some point...

Would be nice if you could share it at the #showcase section of the #freecad forum: forum.freecadweb.org/viewforum

@gbrnt this is an amazing thread and great to look back on. Congratulations so far – it looks amazing!

@ephemeral Thank you! I like to keep the thread organised so it's easy to write a blog post if I feel like it.

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