TornBlue - a bluetooth split keyboard

In this repo you can find information about the TornBlue a bluetooth split keyboard with SMT components. This is an iteration on the Torn, which is a split keyboard using through hole components.

You can ask questions and get help on the Torn Discord channel.

WARNING: These files are provided as a reference for designing keyboard PCBs, without liability and without any guarantees regarding functionality. This is untested work in progress, really don't assume anything here will work.

Features

• nRF52840 using zmk keyboard firmware
• Battery charging for a 3.7v lithium rechargeable battery (JST-PH connector)
• 6x3 or 5x3 layout with detachable outer column
• 3 leds and 1 charging led
• (SOIC test clip footprint) for programming
• Breakout with switchable 3.3v and gpios
• Battery level reported over BT
• Supports soldered Cherry MX compatible or Kailh Choc key switches
• Horizontal reset button (case friendly)
• JLCPCB PCBA (pcb assembly); handsoldering required for underglow leds and JST-PH connector

Optional features:

• Underglow leds
• Optional Panasonic EVQWGD001 wheel encoders

Parts required

• 2x assembled TornBlue Rev 1 PCBs
• 2x 3.7v lithium rechargeable battery with JST connector. SAFETY NOTE: Only use a LiIon battery with over-charging and over-use protection. Check the battery polarity before connecting.
• (Optional) 2x JST-PH connector. 2mm pitch. Side entry. Surface-mounted.
• (Optional) 2 x Panasonic EVQWGD001 wheel encoder
• (Optional) 12 x WS2812B 5050 leds
• (Optional) ST link v2 (or similar) and SOIC-8 test clip for programming the bootloader

Build instructions

You can find full build instructions, and information for different cases.

Components

The main components are:

• Holyiot YJ-18010; this was chosen as it has castellated edges, which is easier hand soldering the module to the PCB.

• XC6220; 3.3V voltage regulator to supply the Holyiot module.

• TP4096 Li-Ion Battery Charger

• SRV05-4 ESD protection for the USB port

• Other parts use 0805 and SOT-23 packages. These larger packages can be hand soldered and are similar sizes for a pleasing appearance. The parts have been laid out horizontally with a consistent polarity to simplify assembly.

Reference designs

The following projects were used as reference designs.

• ZMK hardware design guide (CERN Open Hardware Licence Version 2 - Permissive) - note the battery charging circuit might be unsafe, see this information about TP4056

• isometria75 (BSD 2-Clause License)

• Unified USB type-C PCB (BSD 2-Clause License)

• Nice!Nano

• nRFMicro (Public domain)

• Adafruit nRF52840 (Creative Commons Attribution, Share-Alike)

Showcase