Keyboard Builders' Digest
Save 10% at AKKO DE! Code: KBDNEWS
Keyboard Builders' Digest / Tips & Tricks

Seeeduino Xiao RP2040

Another RP2040-based controller with relatively small form factor: Seeeduino Xiao RP2040.
Published April 24, 2022
Creators! Feel free to tip me off about your keyboard related projects to bring them to 100K readers.

The Seeduino Xiao RP2040 was brought to my attention by MReavley's Slice36 project, and the BLE version was used on filibustercrankcase's Hummingbird too.

This nice little controller board is another in the ever-growing sea of development boards sporting the RP2040 chip.

Product page: this way.

Relatively cheap ($5.4 atm) – compared not just to other Xiao boards but also to other controllers in general.

The form factor is about 1u (21 x 17.5mm) so it's really easy to fit into pretty much any layout. This parameter makes it a good alternative to other small controllers like the Tiny2040, the RP2040-Zero or the RP2040 Stamp.

The number of GPIO pins (11) may scare you off at first sight, but it's more than enough for splits (in theory up to 30 keys per half) even with a basic matrix.

However, and I just learned this recently, with a "real" duplex matrix (bidirectional scan) you can control up to 60 keys with this tiny board. This makes the Seeeduino Xiao RP2040 suitable for driving a 60%-ish keyboard and huge splits alike.

(To be able to benefit from the duplex matrix, at least at the moment, you have to rewrite your custom matrix scanning algorithm for most firmware I guess, except if you use PRK, where this feature is already implemented.)

Do you like this post? Share, donate, subscribe, tip me off!

Published on Sun 24th Apr 2022. Featured in KBD #75 (source).


Bonsai C3 is back!

Check out the Bonsai C3, a Proton C replacement by CustomMK. Back in stock after the chip shortage, readers can get it for a special price now.

STeMCell devboard

The STeMCell is a STM32 based development board with Pro Micro pinout – designed by u/megamind4089.

Tiny2040 controller

Tiny 2040 is another RP2040-based development board, this time by Pimoroni.

Sea-Micro Review

This video review introduces the Sea-Micro, an open source Pro Micro/Elite-C alternative. Posted by flehrad (source).


The Elite-Pi is a new controller by Maple Computing – sporting an RP2040 chip while being compatible with the Pro Micro footprint.

Mikoto controller

Mikoto is an open-source Bluetooth LE nRF52840 microcontroller in a Pro Micro footprint. Designed by zhiayang.