Author Topic: Puzzle-like curved keyboard for rapid prototyping  (Read 983 times)

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Offline v6ak

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    • v6ak
Puzzle-like curved keyboard for rapid prototyping
« on: Wed, 11 March 2020, 18:07:27 »
I am trying to design a puzzle-like keyboard:

* Keyboard should be curved, like Dactyl keyboard.
* Mechanical keycaps (like Cherry MX or similar).
* Keyboard's lowest point should be as low as possible.
* Keyboard will consist of multiple parts, so it is easy to create a modified parts and change it. This should help with rapid prototyping.
* Non-goal: Universal building set for any keyboard. This would be too ambitious and complicated, without enough payoff. I am OK with having ten pieces of puzzle, all belonging to a single finger.

After thinking about that and discussing with various people, I got the following draft of solution:

Case: 3D printed case with hooks and holes. I will probably fork Dactyl.

Electronics: Probably quite inspired by Ergodox. I want even the firmware to be compatible.

Key switches

They cannot be on standard large PCBs (like on Ergodox) due to the curved shape.

Handwiring is theoretically possible, but it is probably painful to swap some pieces of the puzzle. I want it to be replaceable without desoldering and subsequent soldering.

There was an idea to use a small PCB for every switch:

* In order to be removable from the case, it needs to be smaller than the switch – if it was larger, I would not be able to remove it without desoldering.
* The PCBs would be connected intro a matrix by daisy-chaining with others.
* So, the PCB would contain a switch, a diode for anti-ghosting (connected serially with the switch) and four connector or two connectors + two wires.
* I was advised against DuPont connectors due to their reliability.
* The connector needs to be small in order not to increase the keyboard height. Maybe even just a hole in the PCB with a screw.

As you have seen, I don't want to reinvent the wheel. If you know a suitable existing PCB for my needs, I would be glad for that. If not, I would be glad for any pointer to a suitable connector.

(And if you have anything other to note, you are also welcome…)

Offline vvp

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Re: Puzzle-like curved keyboard for rapid prototyping
« Reply #1 on: Wed, 11 March 2020, 18:20:17 »
Katy and "custom topre" keyboards have switches as low as possible.
https://deskthority.net/viewtopic.php?p=357496#p357496
https://deskthority.net/viewtopic.php?p=315159#p315159

Just some inspiration. Dactyl is a good start.

Offline nevin

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  • Location: US
Re: Puzzle-like curved keyboard for rapid prototyping
« Reply #2 on: Wed, 11 March 2020, 18:48:59 »
i've seen dactyl-manuforms wired with hotswap sockets. i would not pull switch from top but it makes a removable circuit....

switches... are the newer choc low profile switches any good? i've seen a couple pcb split boards that use them

connectors... 3.5mm trrs is common between halves or RJ11-ish. if you need more pins, there are various JTAG connectors that would work.
« Last Edit: Wed, 11 March 2020, 18:52:52 by nevin »
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Offline v6ak

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  • Location: Czech Republic
    • v6ak
Re: Puzzle-like curved keyboard for rapid prototyping
« Reply #3 on: Thu, 12 March 2020, 12:36:30 »
Hello,
Thank you for your responses.

* Katy seems to be closer to my goal than Dactyl, but the switches are handwired, which is what I am trying to avoid. Imagine you want to adjust the column for the middle finger. This means you need to desolder a whole column and partially desolder five rows in order to be able to remove the switches and the middlefinger part of the case.
* Custom Topre – looks great and I actually was considering it in the past, but inactivity has caused me to want to make my own. Also, it does not look like there was any idea how to make the connections between switches easily disconnectable.
* Hotswap sockets – they primarily solve a different problem. They could be helpful even in this case, but I would need to adjust the case.
* Connectors – maybe I was not clear enough. Connection between halves is not my concern, I am more concerned about connection between the switches. If I used a large connector there, the lowest row (home low) would need to be higher.

I also have one more idea: Adjust the case to allow pulling wires from the top. This also puts some restrictions to the case design.

So, I currently have two candidates:

a. Pulling wires from the top.
b. Pulling wires from bottom using hotswap sockets.
« Last Edit: Thu, 12 March 2020, 19:43:19 by v6ak »