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New flexible PCB

Alakuu from Skree.us revised his flexible PCBs and designed a new XIAO-Flex MCU breakout board.

KBD.news
Published September 4, 2023
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Marshall Somerville (aka Alakuu/Skree/TheBigSkree) from Skree.us finished his big revision for flexible PCBs in conjunction with a new XIAO-Flex MCU on breakout board that allows for far less time spent on soldering small wires:

The whole build took 21 total solder joints (51 if you count each wire in a parallel set as a joint). Compared to single key amoebas it's an unreal reduction in the time and effort required to build any flat or curve welled keyboard! – Alakuu.

It uses FFC cables to connect to the flexible PCBs for rows, and columns connect with only a single solder joint per column that then plugs directly into the breakout board. This allows for also complete removal of a breakout board + MCU for easier diagnostics and replacement if something goes wrong.

Pic:

The breakout board has actual low voltage cutoff extra circuitry and can either use the included LIR2450 pin cell battery or simply solder on whatever lithium battery connection you'd want!

I also added LED control with a 3.3v driving circuit that can be change with the flick of a switch to a level shifted 5v USB power delivery to the LEDS along with proper led logic voltage. My version 1 of flexible pcbs has sold with rave reviews for about 9 months now, this revision I hope will help people build any flat or curve welled keyboard – Marshall.

These PCBs support Choc v1 or MX switches, but according to Marshall with his design workflow doing custom distances and different switch types is super easy.

Pic:

Finally, the Mk08 (module name) version hit a road bump with the circuit design but when it's revised there will be an up to 12x12 + SPI, I2C (3 and 4) along with multiple free extra GPIO pins all addressable with both FPC and JST-SH connections for builds with or without flexible PCBs.

Pic:

So MX or Choc, LED or not, even screw mounted or simply hotglued, this is a versatile system for all kinds of builds.

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Published on Mon 4th Sep 2023. Featured in KBD #134.


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