Unified daughterboards for custom keyboard designers and users
The Unified Daughterboard Project is an attempt by leading designers in the mechanical keyboard community to standardize the USB daughterboards used for their custom mechanical keyboard projects. It has initially been envisioned by users ai03, Wilba, Hineybush, Xelus, Xondat, aeryxz and Maximillian.
The main characteristic of this daughterboard is to integrate a USB Type C connector and the needed circuitry for USB2.0 operation in a small PCB that can be screwed to a keyboard chassis; this significantly simplifies the assembly and design of the main circuit board.
In its latest version, C3, this daughterboard features:
Adittionally, the C3 version is backwards compatible with both C1 and C2 versions since it has the same dimensions and uses the same screw hole sizes and positions, so keyboards designed using the past versions should also support C3.
The figure below shows the schematic of the C3 version.