FIFTYBTNS prototype


23 Dec 2018, 18:11

Hi all!

Once ago I have posted my 12x4 ortho KB.
That was first and second attempts of making fully functional KB.
Photos and a bit of description are in this comment workshop-f7/please-help-me-finish-my-ze ... ml#p419073 and in next two on same page.
That KB I use everyday at home and it was kind of investigation about how to make low-profle with standard MX-compatible switches.
But I wanted to move further.

So this post is about my attempt of:
- prototyping with EasyEDA and ordering from JLCPCB;
- implementing ideas that I was inventing and keeping in mind for about half a year;
- creating a better low-profile with standard MX-compatible switches;

(and sorry for photos quality)

First thing to mention (and as title says) - this KB have fifty keys.
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Letters with punctuation (which is main layer) resembles QWERTY as much as possible, with keeping square brackets and Return at same places. I did so to make migration to ortho a bit easier than if it were migration to some popular ortho.
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For this prototype I've used Kailh-box-brown-cap-breakers, with "box" removed, have no idea why I cut off "boxes", so don't ask, and reasons for using cap-breakers are:
- I bought them before great reveal of their cap-breaking nature, and just had to use somewhere;
- I had keycaps that easily fall off from ordinary Gaterons after a bit of shaking, but feels quite good on cap-breakers' stems. They fit so nice, so when I pull caps off - they don't rip off switches from top plate;
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To make low-profile switches out of standard MX-compatibles I have cut central plastic pin, which is considered to be spring shaft, but it's not the case for Kailh. Also I have cut a bit of switch housing so that I was able to bend pins to sides and they won't stick out at the bottom.
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Housing design is dictated by two facts (which affected rest of design):
- thickness of an average micro-USB connector is 6mm;
- after inserting MX-compatible switches (modified to "low-profile") into 1.6mm plate - "underplate" part of switch is about 3.4-3.5mm;

So I have designed top and bottom plates to be made of 1.6mm FR4 and intermediate housing layers to be of 1mm FR4. Which are for same price with same material area at JLCPCB, no matter if project is about pcb full of tracks/pads/vias (for 2-layered pcb) or it is just milling. The only necessity - there has to be at least one pad somewhere, to pass JLCPCB's automatic validation.
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From implementing 12x4 I have carried out that having micro-USB connector per side is a good idea in 2 cases:
- ability to connect wire from convinient side;
- having backup connector if first one breaks off, which is not such a rare case with "high" quality china soldering;
And, as I said, micro-USB should fit into 6mm thickness between top and bottom plates.
So considering these points - KB got two special places for side connectors, plus housing part for additional vertical space.
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Another idea that I have implemented - insert diodes into top plate.
Which in combination with "low" MX-compatibles allowed me to refuse using PCB at all and having real bottom housing plate.
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Tracks on top plate are only for rows/columns and are composing matrix of 5x10, which physically looks like this:
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And for usage is converted into this:
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As seen on photos - connections of rows/cols to ProMicro was made with handwiring.
But in next version I plan to make full set of tracks.

To finalize - here is how completely unassembled housing looks like:
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Also, people who already was ordering from JLCPCB knows that minimum order is 5 pics, so I have 4 billets like this:
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If anyone is interested to buy kit or assembled one - I have quite a variety of switches (which needs to be converted to "low MX-compat") and caps. Write me PM and I will create post in the Marketplace with options and prices.
Last edited by q11q11 on 26 Dec 2018, 10:08, edited 3 times in total.


23 Dec 2018, 20:09

I'm unable to use ortho keyboards but I do appreciate the brilliant ideas put together here. Great work.

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