A Kalmar/A. Dux-based 34-key split ortho keyboard. ZMK shield
- power switch
- reset button
- solder jumpers to mount the MCU the same way on both sides
- thumb keys mount at 90° with pogo pins and 3D-printed magnet brackets
- besides Kailh Choc, support for Gateron KS-33, both hotswap only
- ground plane for some ESD protection, new pinout
- JST PH battery connector
- perforations to remove the tab for wired builds
- For wired builds: switched from TRRS jacks to RTLECS magnetic pogo pin connectors (also used to mount the thumb keys) to improve damage resitance
If you don't need fold-down packability or can't get the magnets, you can run a 9mm or longer M2 bolt through both brackets. However, any fall will then be more likely to cause damage.
Consider putting a non-conductive coating between the JST connector's mount points and the battery. Remove remnants of perforations on the thumb-key board before attaching the bracket. Personally, I solder the top-side jumpers to mount the MCUs component-side up so I can see the LEDs, and keep them safe under a case handcrafted from plumbing silicone.
Passed basic testing.
| Item | Qty | Notes |
|---|---|---|
| SuperMini NRF52840 MCU | 2 | inc. sockets. Alternatively, ProMicro/Elite-C for a wired build |
| Kailh Choc V1 | 34 | key switches. Alternatively, Gateron KS-33 |
| Choc hotswap sockets | 34 | Alternatively, Gateron KS-33 hotswap sockets |
| Keycaps | 34 | 1U. If using KS-33 switches, STL files are provided to print your own 'MX stem, Choc-1U-spaced' caps |
| Magnets | 2 | D6×3mm annular cylinder |
| RTLECS MG03254 3-pin | 2 straight m, 2 90° f | magnetic pogo-pin connectors |
| MSK-12CO2 | 2 | power switch |
| SMD button 3×4×2 | 2 | reset switch |
| 301230 li-po | 2 | battery |
| JST PH right-angle 2-pin | 2 | battery connector |
| JST wire | 2 | solder & shrink tube to battery wires, no crimping needed, or battery already with connector |
| M3 machine screws, 3mm | 2 | flathead, couples with magnet |
| M3 thin hex nuts | 2 | |
| M2.5 tapered head machine screws, 7mm | 2 | holds magnet |
| M2.5 thin hex nuts | 2 | |
| M2 flat head machine screws, 8mm | 6 | for brackets |
| M2 thin hex nuts | 6 | |
| OPTIONAL: RTLECS MG03254 cable and extra RTLECS 90° female connectors as listed above | 2 of each | For a wired build: cut, solder and shrink-tube the two wires together |