Tempest Dux
A custom wireless split keyboard combining PCB design, 3D-printed mechanical iteration, ZMK firmware, and an integrated trackball.
Tempest Dux is a wireless split keyboard I built on thrly’s Tempest and the Rae-Dux / Architeuthis Dux ergonomic lineage, adding a custom PCB and an integrated trackball. It exists because no off-the-shelf board matched the split ergonomics and a built-in pointing device I wanted in one unit. The project spans PCB layout, firmware, and a lot of physical iteration.
Why I Built It
I wanted a single device that combined a split ergonomic layout with an integrated trackball, so my hands could stay in one place for both typing and pointing. That combination, in the exact form factor I wanted, was not something I could buy. Building it was also a way to work through a full hardware project: layout, PCB, enclosure, and firmware, rather than just one slice of it.
PCB Design
The board is a custom PCB, laid out with Ergogen and finished in KiCad. The work here was the unglamorous part that decides whether everything else functions: switch matrix layout, controller and trackball placement, power and wireless considerations, and routing that stays sane on a hand-shaped outline. The design went through several revisions as I corrected footprints, spacing, and placement choices that only became obvious once parts were in hand.
Mechanical Iteration
The case and plate are 3D printed, and this is where most of the learning happened. Early prints failed in instructive ways: tolerances that were too tight, mounting points that flexed, and clearances that did not account for the trackball assembly. Each revision fixed a specific problem the previous one revealed. Printing the parts myself made that loop fast and cheap.
Firmware
The keyboard runs ZMK, the open-source wireless firmware, on a Miryoku base, with badjeff’s PMW3610 driver for the trackball. That covers the split-half communication, the wireless link, and the keymap. Integrating the trackball meant wiring the pointing device into the firmware so it behaves as a first-class input alongside the keys, not a bolt-on.
What It Demonstrates
- hardware design from layout to working device
- PCB layout discipline on a non-trivial board
- iterative mechanical design with rapid 3D-printed prototyping
- embedded firmware work and input-device integration
The board files and Ergogen source are on GitHub at samjolley/tempest_dux. Full build write-up: Building the Tempest Dux.