A low-profile wireless split keyboard. Fixed reference point for the Hermatic stack.
made by Christian Faurholt
datum is a 34-key wireless split keyboard based on the Ferris Sweep Half Swept layout, built around a Nice!nano V2 and ZMK firmware. It runs the Gallium columnar stagger layout — an alternative to QWERTY optimised specifically for columnar stagger boards and Rust development.
The name comes from surveying. A datum is the fixed reference point from which all other measurements are derived. The benchmark symbol carved into the PCB is the ordnance survey mark used for exactly this purpose — a point cut into stone at a precisely known elevation, against which everything else is measured.
datum is the physical interface to Hermatic. The one fixed, trusted point where the Hermatician touches the system.
| Property | Value |
|---|---|
| Layout | 34 keys — 3×5 column stagger + 2 thumb keys per half |
| Controller | Nice!nano V2 (nRF52840, wireless BLE) |
| Firmware | ZMK — Gallium columnar stagger layout |
| Switches | Ambients Silent Bokeh Choc v1, 50gf |
| Keycaps | MBK Black 1U, Choc spacing 18×17mm |
| PCB | datum — reversible, black soldermask, ENIG finish |
| Build style | Bare PCB, no case, soldered direct |
| Tenting | Splitkb Tenting Puck + Manfrotto Pocket Tripod per half |
| Battery | LiPo 301230 110mAh soldered direct to BAT+/BAT- pads |
| Connection | Wireless BLE only — no TRRS, no USB data in normal use |
Order from PCBWay using the gerbers in gerbers/datum_gerbers.zip:
| Setting | Value |
|---|---|
| Quantity | 10 (minimum order — use 4, keep 6 as spares) |
| Layers | 2 |
| Thickness | 1.6mm |
| Soldermask | Black (Matte) |
| Silkscreen | White |
| Surface finish | Immersion gold (ENIG) |
| Copper weight | 1oz |
| Item | Qty | Source |
|---|---|---|
| Nice!nano V2 | ×4 | Typeractive.xyz |
| Mill-Max Low Profile Sockets 310 series | ×4 sets | Splitkb.com |
| Reset Button — Panasonic SMD | ×4 | Typeractive.xyz |
| Power Switch — Alps SPDT | ×4 | Typeractive.xyz |
| LiPo 301230 110mAh 3.7V | ×4 | — |
| Item | Qty | Source |
|---|---|---|
| Ambients Silent Bokeh Choc v1 50gf | ×70 | lowprokb.ca |
| MBK Black 1U keycaps | ×70 | lowprokb.ca |
| MBK Black 1U homing keycaps | ×4 | lowprokb.ca |
| Item | Qty | Source |
|---|---|---|
| Splitkb Tenting Puck — Black | ×2 pairs | Splitkb.com |
| Manfrotto Pocket Tripod | ×4 | — |
| SKUF Silicone Rubber Feet | ×16 | Splitkb.com |
datum uses ZMK firmware with the Gallium columnar stagger layout, home row mods, and Rust-optimised combos (::, ->, =>).
Firmware is built automatically via GitHub Actions. Download the latest build from the Actions tab — no local toolchain needed.
See docs/firmware-guide.md for the full layer design, home row mod setup, and flashing instructions.
See docs/build-guide.md for full assembly instructions.
Critical notes before you start:
- The PCB is reversible — close the correct jumper pads before soldering anything else
- Battery polarity is critical — reversed polarity will instantly damage the Nice!nano
- Never solder the Nice!nano directly — always use Mill-Max sockets
datum/
├── pcb/ # KiCad project files
├── gerbers/ # Fabrication files for PCBWay
├── config/ # ZMK firmware config
│ ├── cradio.keymap # Gallium layout, layers, combos
│ ├── cradio.conf # ZMK settings
│ └── west.yml # ZMK dependency
├── build.yaml # GitHub Actions build matrix
├── docs/
│ ├── build-guide.md # Assembly instructions
│ ├── build-guide.pdf
│ ├── firmware-guide.md # ZMK setup, layers, Gallium
│ ├── firmware-guide.pdf
│ └── images/ # 3D renders
└── README.md
MIT