Atlas: October 2026 update
Since June, Atlas changed in a few places: the 20 × 17 mm grid is back with custom keycaps, the board is hotswap, and the ADS1220 trackpoint readout sits on the PCB.
A few things in Atlas changed since the posts from May and June. Some of them reverse what those posts said, so here is where the design stands now.
The 20 × 17 mm grid is back
In June we moved to Choc v2 and planned to switch to the standard 19.05 mm MX pitch, so off-the-shelf keycaps would fit. Choc v2 stayed; the pitch change did not.
The trackpoint sits low, in the shallow valley where four keycaps meet. That means the caps around it need a custom shape anyway, and once the keycaps are custom, the pitch can be whatever suits the hands best. So Atlas is back on its own 20 × 17 mm column stagger, with custom keycaps: 19.5 mm wide, all three rows and the thumbs canted, in a version for Choc v1 and one for Choc v2 stems.
Hotswap
Switches sit in Kailh Choc hotswap sockets, so you can swap them without a soldering iron. Both Choc v1 and Choc v2 low-profile switches fit.
The trackpoint readout is on the board
The ADS1220 path that ran on the bench in May now lives on the PCB, one ADC per half, each reading its own strain-gauge stick.
The bench build needed the XIAO nRF52840 Plus for its extra pins. On the PCB, the key matrix is charlieplexed: 17 keys on 5 lines plus an interrupt pin. That frees enough pins on the standard XIAO nRF52840 for the ADC, so the Plus is no longer needed.
The pin order of the stick’s four contacts is easy to get wrong, so we checked it on the real stick with a multimeter before committing to the layout.
The case
A wooden housing with a printed switch plate and bottom plate. The battery sits in a tray in the bottom plate.
The repo
The Atlas repository is cleaned up to match: STEP files for the case parts, the KiCad project for the board, and the firmware.