deskthority

Edit: (previous title) Another custom split hand Topre board - need your input!

I've been thinking about a similar project to my ongoing one, that is much simpler (I need a split Topre keyboard in my life). I'm interested in it being more community oriented, with design decisions being influenced by anyone who may want one of these keyboards. My other project is very uncompromising, but that means it'll take time (and money).

Specifically I'm looking at making a flat split Topre keyboard. I have a few options now but need to narrow down to a final goal. There's four styles I see being possible, each with positives and negatives:

Style	Supported donors	Keycap requirement	Dome cutting
ErgoDox	Topre + full set MX Sliders	ErgoDox sets	Cut many horizontal strips for columns
Split Planck	Topre	Donor	Cut some horizontal strips for rows
Symmetric Stagger	Topre + few MX sliders?	Donor + few extras	Cut horizontal strips for rows
Split ANSI	ANSI Topre*	Donor + split spacebar keys*	Cut once through middle + extra domes for spacebar

* These is some difficulty here with Realforce bottom row having odd key sizes. Typeheaven looks to be the same. Just means that if a Novatouch or other board were used, there would be some extra keycaps and cutting needed for the bottom row.

Any of these should also work with clone boards, provided they adhere to the rules.

The PCB should be quite simple to design - I will be going with a Teensy 3.1/3.2 on each side. Expensive, but it promotes easy firmware development and no special tooling required. Anyone have any recommendations for low cost PCB houses? I'm not sure I'll be able to get the board down to 2 layers - the controller on my other project is 4 layers. My previous suppliers don't do 4 layer boards in these larger sizes. Probably will have to do some design to figure it out! I'd like to use through hole stuff like the ErgoDox PCBs do. Don't think I'd be able to make it reversible like that though.

All would be plate mounted on 1mm thick laser cut steel / stainless steel. Not decided the finish, that will come later.

Please don't hesitate to post your thoughts!

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I am becoming quite attached to the idea of a split HHKB:

excuse cheaply photoshopped legends



Anyone have any suggestions for the bottom row? There are an additional two 1U keys which could be added, but I like the HHKB style.

It's a very basic design for now, I want a nice tenting solution and easy assembly

Some progress on the split HHKB layout, I think it's a good layout for the fact of not needing anything but a standard Realforce (on that note, I'm now on the market for a 55g 87u in black).

Shows proposed tenting method, using 5 deg high density foam blocks (I want to try moulding some, but the keyboard comes first):


Left PCB is done, managed to squeeze it into two layers (hopefully the parasitic capacitance is controlled still!)


I can't decide: would it be better to keep the standard 2U backspace or go full HHKB and use two 1U switches there?

The right side PCB is almost done, when I am happy I'll send the two off to get prototypes along with plates so that the firmware can be fleshed out with a nice testbed.

Just picked up a 55g 87U, it seems Topre are trying to make my life difficult with their left control key having a rotated stem! I think if I make the plate cutout slightly bigger for the alt and control keys on the left hand side, this should allow rotation of the switch housing so that 1) ctrl and alt keycaps could be switched depending on preference and 2) other Topre boards (without the wonky left control keycap) would be supported. I plan on using the normal 1U housings throughout for the same reasons, but this means no caps lock LED, which I am okay with.

Oh, and 55g is nice to type on.

PCBs arrived and I have soldered all components, unfortunately I used one of the pins I need to pull up to use the debugger (didn't know it needed this). Not the end of the world, see photos for questionable hacks. Once I get the bootloader working I shouldn't need it anyway, but I will probably be redesigning slightly for future PCBs.







Please excuse any flux still on PCBs and possibly questionable soldering. I don't have a proper soldering station.
I have successfully got the boards working with the debugger (it recognises and can write memory). Not figured out how to make my LED blink yet. I have realised that maybe I didn't put some of the stuff in the best position, but it will have to do. This is new territory for me having previously relied on the teensy bootloader.

Also I 3D printed a case and plate for a mockup of the left hand side:

Aw wow, this is really interesting. Don't know how I hadn't seen it before. You don't happen to be bringing this to the London meetup?

scottc wrote: ↑Aw wow, this is really interesting. Don't know how I hadn't seen it before. You don't happen to be bringing this to the London meetup?

Afraid not, it's a bit of a trek from where I am

Got my LED blinking today, just trying to get HaaTa's bootloader working now.

Edit 8th Dec:
Bootloader is working and I've been working on a fork of the Kiibohd firmware. The electronics looks like it is workable, got rid of the resistors but had to put a jumper to one of the pins for voltage reference (missed off the schematic!). It's just a matter of time now unless I run into other issues.

Done:
Bootloader & kiibohd firmware setup
Got mux, amp, and ADC working and can directly read the keys

To do (in no order):
Get keyboard sending keystrokes
Implement EEPROM calibration storage for normalisation
Implement interconnect between halves
Get prototype plates - currently waiting on a quote
Get required fasteners
Print the other half case for testing
Sort out prototype aluminium cases and finishing process for both case and plate

I am typing this message (well half of it) on the left hand PCB. Seems to work! Really I need to get the plates sorted now so I can actually use the keyboard since I'm currently just balancing the bendy plastic prototype plate on the circuit board, making it somewhat of a nightmare with springs occasionally flying everywhere. This is the current setup:



I think the case should be simplified to just being the plate suspended above a piece of acrylic:



Reason being that due to the PCB being somewhat experimental I don't want people having to spend a load on the case to end up with a £200 paperweight. That's the worst case of course - but it would bring the price into a more justifiable range, and there's always the option of producing the case later on. Any thoughts on this? I hope to hit below £100 for all the parts (PCB fully assembled and flashed) with this plan.

Fantastic thread and amazing work!

Keep us posted

attheicearcade wrote: ↑
I think the case should be simplified to just being the plate suspended above a piece of acrylic:

I don't know man...I think you were onto something with the prior design...the classic HHKB empty plastic on the wings of the lower row just has something magic. Plus I am not a fan of floating keys.

In any event, I am stoked on this project.

attheicearcade wrote: ↑I am becoming quite attached to the idea of a split HHKB:

excuse cheaply photoshopped legends



Anyone have any suggestions for the bottom row? There are an additional two 1U keys which could be added, but I like the HHKB style.

It's a very basic design for now, I want a nice tenting solution and easy assembly

No way! You have to keep this layout untouched!
HHKB with such bottom row is a dream keyboard. Not sure about split But any way this is a nice layout!

le_wraith wrote: ↑

attheicearcade wrote: ↑
I think the case should be simplified to just being the plate suspended above a piece of acrylic:

I don't know man...I think you were onto something with the prior design...the classic HHKB empty plastic on the wings of the lower row just has something magic. Plus I am not a fan of floating keys.

In any event, I am stoked on this project.

It is to lower the barrier to entry, given that you will already need a Realforce / TypeHeaven. I think I'll put the case file STLs up so people can 3D print them if they'd like - they will be compatible with the plate and PCB.

Plates arrived today, look really good - minor issues like 2U holes being slightly too wide and the manufacturer thought the bottom side was the cosmetic side. Additionally I think the corners could do with being softened slightly, they feel a little uncomfortable. Should be able to fix those in production runs. I'm waiting on some fasteners to come from Germany, it's tough to find M2 x 4 mm threaded spacers!

Parts all came!







I am experiencing an undesirable squishing sound on releasing keys, not sure what is causing this. To some extent I have experienced this on real Topre boards, but not this bad. Maybe the domes need time to settle (after a while they seem to stick to the PCB).

I'm currently hacking together the code for interconnect over uart. After that, I guess it is ready for a group buy.

Although I said nothing until now, I find this a fascinating project - not sure how much money I can throw in the game, but (depending on what you will come up with), I want at least those PCBs

Yes, really impressed with results so far - I can't believe there hasn't been more interest here! I think I'd be interested in at least some parts too. I have a HHKB I'm willing to sacrifice to the cause. If only it had enough keycaps...

Laser wrote: ↑Although I said nothing until now, I find this a fascinating project - not sure how much money I can through in the game, but (depending on what you will come up with), I want at least those PCBs

PCBs will be the most expensive part by far I think. Expensive components!

scottc wrote: ↑Yes, really impressed with results so far - I can't believe there hasn't been more interest here! I think I'd be interested in at least some parts too. I have a HHKB I'm willing to sacrifice to the cause. If only it had enough keycaps...

HHKB wouldn't work since there aren't enough sliders (assuming you mean you'd chop it in half so it matches the PCBs). It requires an ANSI TKL board at minimum, I think. I'm using a 55g Realforce. I think clone boards should be okay.

This message was typed on the fully working keyboard! Firmware has been thoroughly hacked together, with a rudimentary protocol for sharing the key depth information between the sides. Still squelchy sounds when I bottom out, very frustrating. Maybe talcum powder would help

Dude, you are a hero!

I asked this question on /r/mk and was told it was impossible to have a custom Topre keyboard and then I found this, wow.

Do you mind if I ask you if you would do a custom HHKB with rgb leds and how much it would cost?

bemed wrote: ↑Dude, you are a hero!

I asked this question on /r/mk and was told it was impossible to have a custom Topre keyboard and then I found this, wow.

Do you mind if I ask you if you would do a custom HHKB with rgb leds and how much it would cost?

That should be possible using the RGB realforce, not a project I'm interested in though.

How's the project advancing? (well, I hope)

By the way, it would be awesome to support a "MIDI" mode, in which pressing a key would register not only 0/1 (unpressed, pressed) but an entire range of "how much was the key pressed" - 0/10, 1/10, 2/10 and so on - so that the keyboard would act as an electronic keyboard (when set to work in this mode of course).

Amazing.

Btw, where is the spacebar?

chrisjunlee wrote: ↑Amazing.

Btw, where is the spacebar?

probably the two keys towards the center of the keyboard when split.

Interesting project. Any news? Will there be a GB?

Is the project active?