The BB40 is a compact BlackPill-powered very straightforward 40% keyboard with indicator LEDs under the acrylic BlackPill display guard. The BB40 can be built with either Choc or MX switches.
If you want to build it to work with Bluetooth, try building
with the PillBug and adding a battery.

Build Guide | Firmware Repo | KLE Permalink

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The BB40 is a no-nonsense 40% minimal layout featuring an optional layout to support arrow keys and a position for an encoder in the corner below the top mounted BlackPill. The BB40 also is fully compatible with the PillBug wireless dev board as a replacement for the BlackPill, if you would like to use this board with BlueTooth. The BB40 features a position for 3 status LEDs on the right side in between the mounting positions for the acrylic guard covering the development board of your choice. The BB40 supports MX and Choc switches, both arranged with normal MX spacing.


  • MX and Choc switch support
  • BlackPill powered
  • QMK and ZMK support
  • Optional Encoder
  • Compact 40% layout

Kit Contents:

  • PCB, switch plate, bottom plate
  • Assembly hardware
  • Acrylic guard
  • Encoder & knob
  • BlackPill
  • Status LEDs