fj laboratories

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Kyuu Hotswap PCBs — FJLaboratories

Aftermarket Hotswap PCB's for the Kyuu open-source case — Felix Jen

Released on December 17, 2021

Kyuu Hotswap PCBs

These hotswap PCBs are designed to fit the open-source Kyuu case as part of a not-for-profit re-release. Featuring an individually addressable RGB header for use for RGB light strips (e.g., Neopixel, generic WS2812b, etc…), these boards were designed with frosted polycarbonate cases in mind, but are compatible with any Kyuu case. The included firmware supports up to 16 RGB LEDs for underglow, but the firmware can be modified for a strip of infinite length assuming that brightness limits are kept in mind. Compatible strips operate at +5V nominal voltage and use the WS2812B data-line specification with a single .data line; note that APA102C strips, like those sold by SparkFun, are not compatible.


Images rendered by FJLaboratories on Keyshot. Switches are JWK Tropical Linear switches. Deskmat is an unreleased private design:

Technical Details

Specification Value
PCB Thickness 1.6mm
PCB Material Tg 130-140
Surface Finish ENIG 1U
Copper Weight 1oz/ft2
Soldermask Plum Purple
Maximum Power Consumption 500mA
Standby Power Consumption 12mA
Overall Dimensions 303.8mm x 96.3mm
Microprocessor ATMEGA32U4-MU

Where to Buy

The group buy for the Kyuu Hotswap PCBs have completed at this time. Future runs may occur at an undetermined time.