Left hand only Ergo Dox

[Melvang]

So, I want to build my son and I a pair of left hand only Ergo Dox keyboards for gaming pads.  My question, which PCBs do I need to get. I know there are a few versions, but it has been a good number of years since I have followed anything keyboard related.

[Findecanor]

The original PCB is symmetric, so that would be doable with custom firmware. I think a few people throughout the years have posted that they hade built them, or at least considered to.
But you'd need to build it like a right hand but mirrored, with the components on the opposite site, including the Teensy 2.0 upside-down ... That is if you can get hold of a Teensy 2.0. The original maker: PJRC, has discontinued it and are out of stock. Other stores may have stock left. There might also be a clone of the Teensy 2.0 out there.
None of the ARM-based Teensies from PJRC's current lineup will work - they have a different pin-out, among other differences.

You might want to consider looking at other ergo keyboards too. The convention among DIY ergo-mech keyboards is still symmetric PCBs but with a Pro Micro on each side.
Most keyboards have even fewer keys than the ErgoDox (76-80) though.
I'd suggest looking at the Lily58 (58 keys) or the ErgoDash (66-70 keys)

Here's a site that lists lots of keyboards that lets you compare the layouts: https://jhelvy.shinyapps.io/splitkbcompare/

[Melvang]

The original PCB is symmetric, so that would be doable with custom firmware. I think a few people throughout the years have posted that they hade built them, or at least considered to.
But you'd need to build it like a right hand but mirrored, with the components on the opposite site, including the Teensy 2.0 upside-down ... That is if you can get hold of a Teensy 2.0. The original maker: PJRC, has discontinued it and are out of stock. Other stores may have stock left. There might also be a clone of the Teensy 2.0 out there.
None of the ARM-based Teensies from PJRC's current lineup will work - they have a different pin-out, among other differences.

You might want to consider looking at other ergo keyboards too. The convention among DIY ergo-mech keyboards is still symmetric PCBs but with a Pro Micro on each side.
Most keyboards have even fewer keys than the ErgoDox (76-80) though.
I'd suggest looking at the Lily58 (58 keys) or the ErgoDash (66-70 keys)

Here's a site that lists lots of keyboards that lets you compare the layouts: https://jhelvy.shinyapps.io/splitkbcompare/

I have Teensy controllers covered. I have one I flashed with something not keyboard related with just a couple test wires on it. And another that hasn't been opened.

I am specifically looking for something to be built single sided to use as a Nostromo replacement.

[suicidal_orange]

As long as the PCB has a place to solder the Teensy you can make it work single handed (open source firmware = you can do anything)

The original is as good as any assuming you don't want RGB or hotswap, you can see the PCB has two sets of holes for each switch so you just flip it for left or right hand use and as Fin said solder the Teensy on the back.

[Melvang]

As long as the PCB has a place to solder the Teensy you can make it work single handed (open source firmware = you can do anything)

The original is as good as any assuming you don't want RGB or hotswap, you can see the PCB has two sets of holes for each switch so you just flip it for left or right hand use and as Fin said solder the Teensy on the back.

Wasn't there an online utility where you could setup your layout and it would output a TMK firmware?

[Captain Proton]

So, I want to build my son and I a pair of left hand only Ergo Dox keyboards for gaming pads.  My question, which PCBs do I need to get. I know there are a few versions, but it has been a good number of years since I have followed anything keyboard related.

For the latest revision PCB resource, Profet Keyboards has a Gamepad version of the PCB on his shop, it's where I acquired mine. Ergodox.io has a couple more you could check out.

For firmware, the easiest resource would be the ErgoDox Configurator:https://configure.zsa.io/ergodox-ez/layouts/default/latest/0

The ErgoDox EZ would be the firmware that should work with the Gamepad. One note, at one point I heard that the firmware would lock up if there wasnt two halves connected, IDK if that was an actual issue and/or if it was fixed. Massdrop also has a Configurator that may work.

If you're looking for real nitty gritty, QMK is the base firmware and is really well documented on how to build your own. There's already the keyboard files, you would just have to edit the layout.

And finally, here's a good resource with basic instruction for the actual build: https://imgur.io/a/zog7Z

Good luck and have fun!

[Captain Proton]

So, an adjustment to the configurator suggestion.

VIA would actually be a better choice, I'd say. You could use the default firmware they provide, and there's a in-browser on-the-fly layout editor that bypasses the need to flash a new firmware any time you want to adjust it. I would've mentioned it before, but I forgot they had prebuilt firmware.

With the gamepad setup, because you are flipping the board over, in any configurator you will have to make the layout mirrored. Essentially, "flipping the board over" in terms of the layout. Following is the example of my default layout: