Project by Zufi Christian— God's Chosen Engineer
Twice: 34-Key Wireless Split Keyboard
In Progress
Duration: Ongoing
Overview
Twice is a 34-key column-staggered split ergonomic keyboard I'm building from scratch. The layout is generated parametrically with ergogen, the PCB is designed in KiCad, and it runs ZMK firmware for fully wireless Bluetooth operation across both halves.
The name is a nod to Twice from My Hero Academia, whose quirk creates perfect duplicates of anything he touches, fitting for a board that splits into two identical halves. Each half is the mirror of the other, talking over BLE with no cable between them or to the host.
The goal is a compact, low-profile daily driver: 34 keys arranged as 3x5 + 2 thumb keys per half, leaning on home-row mods and layers instead of extra rows. Per-key addressable RGB adds underglow and per-layer lighting cues, and the whole thing is tuned for low latency and long battery life.
Key Features
34-key split layout
Column-staggered 3x5 + 2 thumb keys per half, optimized for home-row mods and layers.
Wireless over Bluetooth
Both halves run ZMK and communicate over BLE, with no cable between halves or to the host.
Per-key RGB lighting
Addressable WS2812 LEDs for underglow and per-layer lighting cues.
Parametric design
Layout, switch positions, and PCB outline generated with ergogen so the whole board is configurable.
Challenges & Solutions
Challenge
Keeping both halves in sync wirelessly with low latency and good battery life.
Solution
Used ZMK's split BLE transport with a central/peripheral setup and tuned deep-sleep and power settings.
Challenge
Routing a compact PCB for 34 keys plus RGB data lines.
Solution
Generated the matrix and outline from ergogen, then hand-routed power and the WS2812 data chain in KiCad.
Technologies Used
ErgogenKiCadZMKBluetooth LEnice!nanoWS2812 RGBDevicetreeC
Next Steps
- •Finalize the case and 3D-print plates
- •Flash ZMK and tune the keymap with layers and home-row mods
- •Add RGB animations and a battery-level indicator