Author Topic: [IC] Conundrum - split 40% electro-capacitive keyboard  (Read 2023 times)

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Offline mewa

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  • Posts: 5
[IC] Conundrum - split 40% electro-capacitive keyboard
« on: Wed, 31 October 2018, 20:53:54 »
Hello Geekhack,

Recently, I've been working on a custom electro-capacitive keyboard and I decided it's time to shed some light on it.

The keyboard is named Conundrum and will have a split 40% ortholinear layout (2 pieces with 6x4 keys laid out in a matrix). It will be fully programmable and come fully assembled (without keycaps).

I have just received PCB prototypes and I thought it's a good moment to share some renders and photos and to describe where the project it at.

Being an EC keyboard, Conundrum is actually a bit more complex than a traditional mechanical keyboard and consists of several components:
1. PCB
2. springs (over PCB)
3. rubber domes (over springs)
4. case
5. firmware

I've been working on each of them with some success and I'm on a good way to bringing this project to fruition. I'd like to be pretty transparent about what I'm doing and what is the progress.

First of all, the springs - springs used in such designs aren't readily available, so they had to be designed and manufactured for this specific use case. I have already received some prototypes from the factory and - while they were a bit too stiff, something I have addressed in the 2nd revision - they did work correctly with "major brand's" electro-capacitive keyboard PCB. 2nd prototype batch is on the way.



As for the rubber domes, I decided their characteristics might be too hard to reproduce efficiently (both time- and money-wise), and instead I have contacted a reputable manufacturer. I won't be disclosing the details just yet - all I can say at the moment is that you won't be disappointed.

The PCBs have just arrived and have already been soldered by me and the board seems to work properly (in spite of my miserable 0402 soldering skills  ;))



With the advent of the PCBs, work on the firmware has accelerated as it's no longer a black box and I'm currently working on integrating capsenses with QMK firmware.

Last but not least, they keyboard case. I started playing around with CAD software and created a prototype case (angled, 5deg). However, case hides another crucial aspect of the keyboard - housings and sliders.



First of all, both the slider and housing will be "non-standard" and will be tailored to each other (technically, they already are, as the CAD models are ready, but I will be making some adjustments) . The reasoning behind is quite simple - it's impossible for me to measure (with enough precision) the diameter of the slider - and if I were to rely on caliper measurements solely, I'd risk producing either a scratchy or wobbly switch. And while theoretically it's possible to iterate on the design, the costs will accumulate very quickly as the molds are expensive as hell. By designing my own slider there are much better chances of avoiding these issues and nailing it in the first run.

Besides, the inner inventor of mine wanted to experiment a bit.

I'm attaching some images:
https://imgur.com/gallery/RD7TVyd

If what I described sounds interesting and you're interested in participating in the group buy, please let me know in this form: https://goo.gl/forms/yxfhk1UPzXfu2Bax1

This will help me gauge interest effectively and negotiate particular terms with manufacturers. Your e-mail will only be used for the purposes of informing you of the group buy when it starts.

Offline fcoury

  • Posts: 53
  • Location: Brazil
Re: [IC] Conundrum - split 40% electro-capacitive keyboard
« Reply #1 on: Wed, 31 October 2018, 20:55:36 »
Donít want to wait. Give me one right now at once! Seriously though, amazing project, totally in.

Offline funderburker

  • Posts: 907
  • Location: Latvia, Riga
Re: [IC] Conundrum - split 40% electro-capacitive keyboard
« Reply #2 on: Thu, 01 November 2018, 04:09:44 »
Finally, a EC board design. I wish you the best but a lot of people have tried and a lot have failed. Will keep an eye but this would have to be Kickstarter probably to reach the manufacturing cost goals. :thumb:

Offline Wetherbee

  • Posts: 201
Re: [IC] Conundrum - split 40% electro-capacitive keyboard
« Reply #3 on: Thu, 01 November 2018, 04:15:29 »

Seems like there is still a lot of research and development needed. However, if you've cracked the custom capacitive PCB there are some case makers who would be especially interested in doing a collaboration. One option to make sure this work sees the light of day.

Offline Zilleon

  • Posts: 43
Re: [IC] Conundrum - split 40% electro-capacitive keyboard
« Reply #4 on: Thu, 01 November 2018, 06:06:32 »
This is outstanding!

I'm totally in, although I have to say that I'm sad that it's not 6x5 :(

Online senter

  • * Maker
  • Posts: 586
  • Location: Shenzhen, China or Washington, D.C.
Re: [IC] Conundrum - split 40% electro-capacitive keyboard
« Reply #5 on: Thu, 01 November 2018, 12:33:42 »
This is dope. Great work OP!

I'm curious, will the slider housing also be made with aluminum? It seems like so in the render.

Offline mewa

  • Thread Starter
  • Posts: 5
Re: [IC] Conundrum - split 40% electro-capacitive keyboard
« Reply #6 on: Fri, 02 November 2018, 17:58:53 »
Cheers for the enthusiasm everyone!

I'm curious, will the slider housing also be made with aluminum? It seems like so in the render.

That's something that's yet to decide, I have considered both standalone plastic and built-in housings. For now my priority remains the firmware.

Seems like there is still a lot of research and development needed. However, if you've cracked the custom capacitive PCB there are some case makers who would be especially interested in doing a collaboration. One option to make sure this work sees the light of day.

I think I'm close to cracking it, although things are progressing slower than I wished for as I have a day job I need to take care of.

As for collaborating with case makers - it's a valid idea. Thanks, I'll have to look into it.


Online mrpetrov

  • Posts: 142
Re: [IC] Conundrum - split 40% electro-capacitive keyboard
« Reply #7 on: Thu, 15 November 2018, 18:34:18 »
uber cool and really pushing the hobby forward - thanks for sharing!