Picachoc36

PicaChoc36

Low-profile split keyboard with 36 keys using XIAO controllers.

Pica pica - european (common) magpie

Features

• reversible PCB
• 36 soldered ChocV1 keys
• wired/wireless versions
• top pinky key moved to side
• 3D printed case

Wired version

• XIAO RP 2040 controller
• QMK firmware
• TRRS or USB-C connection between halves
• rotary encoder on one side
• one status LED

Wireless version

• XIAO BLE controller
• [TODO] ZMK firmware
• rotary encoder on both sides (ZMK supports only main side for now)
• on/off toggle
• battery connectors

Photos

wired version with 3d printed case

build process

battery compartment

Firmware

• QMK - my fork, compiled file
• Vial - my fork, compiled file
• [TODO] ZMK

Gerber files

• PCB

Case files (STL - 3d printed)

Updated wired cases render:

• Wired - Left, left without encoder hole, right, right without encoder hole
• Wireless - with battery compartment and encoder holes - left, right
• [Experimental] Knob for low profile rotary encoder

Bill of materials

• PCBs
• 3D printed case
• 2 XIAO MCUs - RP2040 for wired version, nRF52840 for wireless
• 36 Choc V1 switches
• 36 SMD SOD-123 1N4148 diodes
• 1 or 2 EC11/12 rotary encoder with knob, low profile is recommended
• [Wired only] 2x USB-C 16pin connector and TRRS jack
• [Wired only] USB-C or TRRS cable
• [Wireless only] 2x Li-Ion 3.7V battery (battery compartment suited for 5×12×21 size)
• [Wireless only] 2x on/off toggle MSK-12C02

Build log

TODO

Similar to all other keyboards. Main points:

• solder diodes on top side
• solder jumpers - choose wired or wireless on both sides
• for wired version only - solder "no enc" jumper on the side that does not have encoder
• for wireless version only - solder on/off switch on top side
• if you want USB-C connection, I recommend to solder both TRRS and USB-C to have a backup option, better safe than sorry. Check USB-C pins with multimeter for shorts/continuity, test that encoder works (it uses connection between splits)

⚠️ It's not possible to disassemble the keyboard after soldering switches, so before that:

• flash your MCUs with a firmware that supports bootmagic/QK_BOOT/&reset functions
• triple check all keys with tweezers

Development

For proper KiCad setup install my zzkeeb library.