how to connect left & right halves of DIY split keyboard?

[wolfv]

What is the best way to connect left & right halves of a split keyboard with a 1.5-meter long wire?

I want to cut two CM QuickFire key boards in half to build a split keyboard similar to leeku's split keyboard.

leeku's keyboard: http://geekhack.org/index.php?topic=40880.0
CM QuckFire Rapid keyboard: http://www.cmstorm.com/en/products/keyboards/quickfirerapid/

This will be my first keyboard build, so I really appreciate it if someone could point me in the right direction.

[Lanx]

it can get messy, you can see my keyboard build with full pics in my sig for reference.

[wolfv]

Thanks Lanx.  The left and right halves of the split keyboard will be separated by a meter.  I need advice on how to wire the two halves together.

I took a closer look at how ErgoDox keyboards are connected:

• The left ErgoDox contains a MCP23018 I/O expander.
• The right ErgoDox contains the Teensy processor.
• The MCP23018 I/O expander and Teensy are connected by a long wire.
• The expander consolidates the left switch signals and sends them to the Teensy.

I don't see how this could be done with the processor that comes with a one-piece keyboard.
The easiest option would be to buy a Teensy + MCP23018 and wire like EroDox.  Please tell me if there is a simpler solution.

Thank you.

[Lanx]

i guess that depends on your controller and matrix,, i can offer to tell you that i used a generic 20$ logitech controller for my first build it was easy, i then used a logitech g15, and that was HARD, cuz it had the "gaming" keys WASD wouldn't ghost, and these keys usually piggy back on like print screen and whatever to avoid ghosting. i had double the amount of wires, just for those 4 stupid keys.

[SmallFry]

I'm not sure you follow exactly what Leeku's board is, since it is not an Ergodox. It is a lot alike it, since Litster released all of the case files etc, but that board, well technically two, is based upon two Logitech K270 controllers spaghetti wired in. The eDox is a wired keyboard powered by a Teensy and then linked with an IO expander making the board connected by a wire between the halves, and a wire to the computer via USB.

[wolfv]

Thanks Lanx and SmallFry.

My keyboard will be similar Leeku's in that the staggered-row PCB is cut from a one-piece donor keyboard.
My keyboard will also be similar an ErgoDox in that the left & right halves are connected by a wire (not wireless like Leeku's).

Would this work?:
Connect the left keyboard's switch matrix to the switch matrix in the right keyboard.
So the left & right keyboards would be connected by about ten 1.5-meter long wires.
Would the 1.5-meter long wires have too much impedance for the controller?
Has anyone tried this before?

[wolfv]

suka made a split keyboard that connects the left and right switch matrices with wire and no I/O expander (instead of wireless like leeku or wired with I/O expander like ErogDox).
Here is a picture of it:

I think this would be the simplest way.
But suka's wire is rather short.
My wire would be 1.5 meters long.
Would 1.5-meter long wires have too much impedance for the little controller?
Have you ever seen left & right keyboards connected like this using a long wire?

suka's keyboard collection is posted on: http://deskthority.net/posting.php?mode=reply&f=7&t=2534&sid=634f6d6d8f07e65e4c9e576762ad8d11

[tp4tissue]

suka made a split keyboard that connects the left and right switch matrices with wire and no I/O expander (instead of wireless like leeku or wired with I/O expander like ErogDox).
Here is a picture of it:

Show Image

I think this would be the simplest way.
But suka's wire is rather short.
My wire would be 1.5 meters long.
Would 1.5-meter long wires have too much impedance for the little controller?
Have you ever seen left & right keyboards connected like this using a long wire?

suka's keyboard collection is posted on: http://deskthority.net/posting.php?mode=reply&f=7&t=2534&sid=634f6d6d8f07e65e4c9e576762ad8d11

wire will be "fine"... I don't see a problem.. at worst it doesn't register, when you press down too many keys.

[blueSmoke]

I am not sure of the mechanical switch/controllers, but I have converted a Kinesis freestyle split keyboard (Rubber Dome) from 20 inch long wire to 8-feet one and it is working ok. Have not done any extended test for interference though.

The original had has 32 thin wires inside a wire-mess grounded jacket and the one I made has same 32 wires but no jacket; and it works. Have no picture, i am away from home.

[wolfv]

Thanks blueSmoke.  That gives me confidence to proceed .

[blueSmoke]

It brings me shivers thinking about how I have done that and how much time/money I spent on searching for alternatives. Think about soldering 20-26 pieces of #32-#36 gaze multi-strand wires connected to two connectors little thicker/wider than ipod connectors. No wonder kinesis is selling the 20 inch ones at between 20-50 bucks each.

Thought about selling the cable on the bay for 100 bucks since I am not using the keyboard, but the thought of building another cable drives down that thought.

Anyway back to the topic.

Good luck to your project.

[wolfv]

blueSmoke,

Thanks for the warning.  Bluecar5556 did something similar with Kinesis Contour Classic (Advantage) Keyboard
He joined left & right keyboards with two 15-pin D-sub VGA cables : http://www.overclock.net/t/961781/split-kinesis-contour-classic-advantage-keyboard-2-vga-mod

I am looking into modifying an ErgoDox kit to avoid all that wiring.