Author Topic: Alternate connectors for split keyboards  (Read 11741 times)

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Offline yoippari

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Alternate connectors for split keyboards
« on: Wed, 16 August 2017, 03:30:14 »
Is there a specific reason the community seems to have settled on trrs connectors to connect split keyboards? Was it just that one of the earlier splits used it and it became default or is there a specific benefit? Just that they are easy to find in male-male cables?

Why not an RJ45 plug or even RJ11. Easy to make exactly the size you want. I kinda like the round DIN plugs myself though that's more for an old school AT keyboard style. Looks like these are in use in the sound industry so the cables are actually available.


Offline Phenix

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Re: Alternate connectors for split keyboards
« Reply #1 on: Wed, 16 August 2017, 03:41:10 »
Space? TRRS jacks are small, while DIN requires more space
Winter is coming.

Offline tobsn

  • Posts: 216
Re: Alternate connectors for split keyboards
« Reply #2 on: Wed, 16 August 2017, 04:49:10 »
Space? TRRS jacks are small, while DIN requires more space

Theyre actually 6mm tall, meaning they'll add an additional 3mm at the bottom of your PCB which makes it harder to make slim cases. Would be nice to find a good alternative... micro/mini usb might be one by just using only a few of its pins.

Offline Findecanor

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Re: Alternate connectors for split keyboards
« Reply #3 on: Wed, 16 August 2017, 05:37:59 »
Registered jacks should be called that only when used for specific telephone signals. The connectors for RJ11 and RJ45 are called modular connectors.
Jacks made especially for RJ45 also contain transformers, which would mess up TTL level signals.

I like modular connctors. The sockets have small footprint on the PCB and the cables are inexpensive, easy to do yourself and the plugs are short so there is no stiff part sticking out.
I find it difficult to find one that is not very high, though. I have not found a socket that goes inside a cutout in the PCB like some mini/micro-USB sockets.
The Ultimate Hacking Keyboard uses a 4P4C socket that is relatively small but I have not found any like it.

4P4C is enough for I2C, V+ and GND.
I have looked at 6P6C because it would also be able to carry a pulse width-modulated current for the Caps Lock LED, giving the builder a choice between the LED in the Caps Lock key itself on the left side and a dedicated LED area on the right.

The "VE.A" keyboard uses 7-pin SATA connectors. The plugs are small. The sockets are also small while still being through-hole that can be soldered by hand, but the cables are very stiff and were never designed for many reinsertions.

... makes it harder to make slim cases.
"Floating keys" looks like crap anyway...
« Last Edit: Tue, 09 July 2019, 12:43:09 by Findecanor »

Offline 0100010

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Re: Alternate connectors for split keyboards
« Reply #4 on: Wed, 16 August 2017, 07:49:24 »
Could use ribbon cables / connectors too (like IDE); just with the number of pins you need for rows / columns / +V / G / LEDs.
  Quoting me causes a posting error that you need to ignore.

Offline yoippari

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Re: Alternate connectors for split keyboards
« Reply #5 on: Wed, 16 August 2017, 21:34:02 »
Regarding ribbon cables I toyed with the idea of an HDMI cable. I think it's 18 or 20 pins which is more than enough for a split.

So height and replugability seem to be the main issues.

I mean USB seems like it should be the standard but usb c to usb c seem to be uncommon still. Even matching usb A to A or micro to micro are less common than it seems they should be. You could go A to micro but then the PCB gets more complicated as you need to accommodate two different ports. Is there a good way around this for USB?

Offline tobsn

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Re: Alternate connectors for split keyboards
« Reply #6 on: Thu, 17 August 2017, 20:17:24 »
"Floating keys" looks like crap anyway...

It raises the total height, floating key or bezel around them - its below the pcb.

Offline obfuscated

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Re: Alternate connectors for split keyboards
« Reply #7 on: Fri, 18 August 2017, 14:25:09 »
My next split will use male-to-male micro usb connectors. Finding breakout boards for the micro usb was pretty easy.
Finding a male-male cable was really hard and time consuming, because most of the search results were for male micro to usb-a cables.

I won't have a pcb.

Offline Phenix

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Re: Alternate connectors for split keyboards
« Reply #8 on: Fri, 18 August 2017, 15:33:33 »
My next split will use male-to-male micro usb connectors. Finding breakout boards for the micro usb was pretty easy.
Finding a male-male cable was really hard and time consuming, because most of the search results were for male micro to usb-a cables.

I won't have a pcb.

can you link me to your sockets?
I want screw-in micro usb sockets (panel mount), and not just breadboards
Winter is coming.


Offline _haru

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Re: Alternate connectors for split keyboards
« Reply #10 on: Fri, 01 September 2017, 19:18:11 »
I don't like TRRS too much. Bit too annoying/small for my taste. I'm going to use RJ11 connectors for my upcoming Let's Split. Since I'm using only as bottom/top plate with spacers, I can simply mount the breakout board to the bottom with double sided tape :)
AMJ60 - 45g MX White | GH60 Rev. C - Ghost Gateron Blacks | DFK101 - Alps SKCM Cream | Filco Majestouch 2 TKL - 62g Vintage MX Ergo Clear

Offline Tshort

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Re: Alternate connectors for split keyboards
« Reply #11 on: Sun, 03 September 2017, 09:22:26 »
On my Dactyl fork, I've been happy with RJ-9 connectors with a telephone handset cable. But, that design has tons of space for the connecting ends. I thought of using USB, but I liked having a different connector given that each side has its own USB connector for connecting to the computer.

https://geekhack.org/index.php?topic=88576.0

Offline yoippari

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Re: Alternate connectors for split keyboards
« Reply #12 on: Tue, 05 September 2017, 14:51:56 »
I figure anything you mean to tent would have a lot of room for whatever connector you want. A dactyl would also have the benefit of the 3d printed shell to mount the connector on. Along with being effectively hand wired would allow for some nice flexibility.

Offline spindle

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Re: Alternate connectors for split keyboards
« Reply #13 on: Wed, 06 September 2017, 04:19:02 »
In one of my split boards, I use a wireless connection between the halves:


Both halves can also connect wirelessly to a USB dongle

Offline FletchINKy

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Re: Alternate connectors for split keyboards
« Reply #14 on: Wed, 06 September 2017, 07:27:24 »
Regarding ribbon cables I toyed with the idea of an HDMI cable. I think it's 18 or 20 pins which is more than enough for a split.

So height and replugability seem to be the main issues.

I mean USB seems like it should be the standard but usb c to usb c seem to be uncommon still. Even matching usb A to A or micro to micro are less common than it seems they should be. You could go A to micro but then the PCB gets more complicated as you need to accommodate two different ports. Is there a good way around this for USB?

I spent a bit of time researching cables with enough pins for a hardwire remote matrix, and ruled out HDMI. The details are a bit fuzzy, but it was something about the different gauges (or twisting?) of cables creating crosstalk when sensing... But that seems odd. I never tested it. I wound up going with a USB type C. Male to male were easy to get, and breakout boards were... well... expensive... but worth testing.

Offline macroxue

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    • Darknight: DIY 60% Split Keyboard
Re: Alternate connectors for split keyboards
« Reply #15 on: Sat, 02 December 2017, 18:40:26 »
I spent a bit of time researching cables with enough pins for a hardwire remote matrix, and ruled out HDMI. The details are a bit fuzzy, but it was something about the different gauges (or twisting?) of cables creating crosstalk when sensing... But that seems odd. I never tested it. I wound up going with a USB type C. Male to male were easy to get, and breakout boards were... well... expensive... but worth testing.

Hey, how did USB type C cable work out for you? I've been toying with the same idea lately. I just got two breakout boards for $12 and a 10Gbps gen 2 cable (1m long) for $13, all from Amazon. Initial testing with a multi-meter shows 15 usable connections, enough for any keyboard layout. I plan to build a new split keyboard with this cable in the next few weeks. Hopefully I will have good news to report back.
[Darknight: DIY 60% Split Keyboard](https://github.com/macroxue/keyboard-diy)

Offline macroxue

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    • Darknight: DIY 60% Split Keyboard
Re: Alternate connectors for split keyboards
« Reply #16 on: Sun, 17 December 2017, 23:52:30 »
USB type C (10Gbps) cable worked out for my new 60% split keyboard. The small breakout boards were not much useful since I couldn't get wires soldered on them cleanly. I ended up cutting off the plugs from the cable and soldering the wires to the matrix directly.

There are 15 usable wires in the cable plus the ground. However, 4 are super-thin so I combined them into one. Also I didn't bother to untwist a twisted pair. So I ended up using 11 wires, good for my 5x6 half matrix. (This Wikipedia page explains the wiring well: https://en.wikipedia.org/wiki/USB-C.)

For this build, I had to ground the tin-plated ground wire/wrap, which I didn't do with my previous builds using ribbon cables. Otherwise, ghost keys kept coming up.

The cable was more than 3 feet long and now it's about 2 feet visible between the two splits. I like the extra length so I can play with the distance between the splits and find out the most comfortable positions.

Hope this helps.
[Darknight: DIY 60% Split Keyboard](https://github.com/macroxue/keyboard-diy)

Offline Tom_Kazansky

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Re: Alternate connectors for split keyboards
« Reply #17 on: Fri, 02 February 2018, 20:35:32 »
HDMI cables are viable but only 14 out of 19 pins are usable.

the unusable ones are: 2, 5, 8, 11, 14 (the "shield" and "reserved" pins)

I found that out the hard way
187765-0
you can see there are 2 "external" wires.  :'(

if I had known this before hand, I should have reduced the number of keys (thus, less pins usages).

p.s: should get myself a new pair of wristrest. :D

Offline keyboardguru1523

  • Posts: 2
Re: Alternate connectors for split keyboards
« Reply #18 on: Tue, 03 September 2019, 16:12:59 »
HDMI cables are viable but only 14 out of 19 pins are usable.

the unusable ones are: 2, 5, 8, 11, 14 (the "shield" and "reserved" pins)

I found that out the hard way
(Attachment Link)
you can see there are 2 "external" wires.  :'(

if I had known this before hand, I should have reduced the number of keys (thus, less pins usages).

p.s: should get myself a new pair of wristrest. :D

Where from you got that keyboard or keyboard kit? I am intrested.

Offline Tom_Kazansky

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Re: Alternate connectors for split keyboards
« Reply #19 on: Wed, 04 September 2019, 01:46:05 »
HDMI cables are viable but only 14 out of 19 pins are usable.

the unusable ones are: 2, 5, 8, 11, 14 (the "shield" and "reserved" pins)

I found that out the hard way
(Attachment Link)
you can see there are 2 "external" wires.  :'(

if I had known this before hand, I should have reduced the number of keys (thus, less pins usages).

p.s: should get myself a new pair of wristrest. :D

Where from you got that keyboard or keyboard kit? I am intrested.

it's a project of mine, though it's a mess, I really can't sell it.
I may restart this in the future, no promises, though.  :))

Offline keyboardguru1523

  • Posts: 2
Re: Alternate connectors for split keyboards
« Reply #20 on: Wed, 04 September 2019, 07:12:16 »
HDMI cables are viable but only 14 out of 19 pins are usable.

the unusable ones are: 2, 5, 8, 11, 14 (the "shield" and "reserved" pins)

I found that out the hard way
(Attachment Link)
you can see there are 2 "external" wires.  :'(

if I had known this before hand, I should have reduced the number of keys (thus, less pins usages).

p.s: should get myself a new pair of wristrest. :D

Where from you got that keyboard or keyboard kit? I am intrested.

it's a project of mine, though it's a mess, I really can't sell it.
I may restart this in the future, no promises, though.  :))

Oh thats hecking cool! Can you tell me how you did it? I am intrested to build one myself. :)

Offline Tom_Kazansky

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Re: Alternate connectors for split keyboards
« Reply #21 on: Wed, 04 September 2019, 08:22:07 »

Oh thats hecking cool! Can you tell me how you did it? I am intrested to build one myself. :)

there are tons of tutorials for this, you can start here: https://github.com/ruiqimao/keyboard-pcb-guide  :)