OddBall Split Keyboard W/ Trackball (34mm)

OddBall Split Keyboard

The OddBall was designed mainly as a learning project to help me better understand how wiring a trackball breakout board works with ZMK before eventually designing my own PCB.

It is a fully hand-wired split keyboard with an integrated PMW3610 trackball.

Materials Needed

• Filament of your choice - I went with ASA - GF

• 1x PixArt PMW3610 Trackball Breakout Board
  PMW3610 Breakout Board by Randware

• 1x 34mm trackball of your choice

• 3x 2mm ceramic ball bearings
  I promise, if you skip these, the trackball will not feel nearly as good.

• 8x M2x8 hex bolts

• 1x M3x8 hex bolt

• 8x M2x4 heat-set inserts

• 1x M3x4 heat-set insert

• 2x nice!nano V2 controllers
  Clones are completely fine too. Just test them before wiring the entire board.

• 2x lithium-ion batteries
  I used 800mAh batteries, but I should have just gone with 1500mAh. There is plenty of room.

  Make sure you read the datasheet/specifications for whatever battery you choose and compare the dimensions to the available space in the case.

  Maximum internal case height is approximately 13mm, not including the bottoms of the switches. I would personally consider around 7mm battery thickness or less a safe target to leave room for flex from heavy typing or pressing down on the keycaps.

• 58x through-hole diodes
  I use Bojack 1N4148 diodes in basically all of my builds.

• 58x MX switches of your choice

• 1x Choc switch of your choice
  I used a Choc V1 Box White that has been "neutered" by removing the click bar.  I also included a custom Keycap for the mouse key, would look great resin printed. 

• 2x Nextpal “x004UR5F2D” latching push buttons.

Wiring

There are plenty of great videos on YouTube showing how to hand-wire a keyboard matrix, so I won't try to reinvent the wheel here.

One thing to note: the innermost thumb key is intended to be a standalone, directly wired key, rather than being part of the main matrix.

If you're new to ZMK, don't like coding, or just want to make the firmware side easier, I highly recommend ZMK Shield Wizard:

https://shield-wizard.genteure.com/

You basically enter how you wired your keyboard and it spits out working firmware/configuration files. It makes getting a custom hand-wired board running significantly easier. You will still need to do your own keymap, but it will walk you through that process once you get your Github Link.

Controller Mounting

You may notice a few holes near the controller seats. I originally added these because I intend to design some sort of retaining clip for the controllers.  When i find time to design a decent lock ill update this page.

In the meantime, hot glue wins.

The PMW3610 breakout board is also held in place with hot glue. I currently have no plans to design dedicated retaining hardware for it because hot glue works perfectly, the board is completely hidden once assembled, and it makes removal fairly easy if I ever need to replace it.

Files

I have included all of the files that should be needed to build your own OddBall.

Feel free to download them, modify them, remix the design, or improve anything you think could be better.

If something about this build is hot garbage, I genuinely want to hear about it. That just means the next board will be a little bit better.

If you build one, please leave a review and share some pictures. I'd love to see someone else rocking one of my boards.