mini36 and mini42 Documentation

Introduction

The mini36 and mini42 are low profile, split, ergonomic, mechanical keyboards with 36 or 42 keys, respectively. The RP2040 processor runs QMK Vial firmware from 16 MB of flash memory. The industrial design features an anodized aluminum case with shine-through backplate, per-key LED lighting, and an OLED display on each half. The processor and display are integrated with the main board (no Pro Micro socket) and low profile connectors are used for an overall case thickness of only 8mm.

Firmware

The mini36 and mini42 currently ship pre-installed with QMK firmware with Vial GUI support. The RP2040 processor includes a UF2 bootloader. New firmware can be loaded by double pressing the RST button on each half of the keyboard or holding the upper left key on the left unit while plugging in the left half to USB, or holding the upper right key while plugging the right half into USB.

Keymap Customization

Keymaps and LED lighting can be customized interactively using https://vial.rocks/ Keyboard behavior can also be changed by customizing the firmware itself. Details on QMK firmware can be found at https://qmk.fm/. The pre-loaded firmware is from the Vial fork of QMK.

Key Switches and Key Caps

The mini36 and mini42 keyboards are designed only for Kailh PG1350 "chocolate" low profile keyboard switches. They do not support MX switches.

Key caps must be compatible both with chocolate switches and chocolate key spacing (18mm horizontal and 17mm vertical). Kailh "pudding" style chocolate key caps and MBK chocolate key caps are known to be compatible. Kailh "crystal" acrylic chocolate key caps and other chocolate key caps for MX spacing (19mm x 19 mm)  are not compatible.

Hardware Specification

Processor: RP2040 by Raspberry Pi Foundation

Flash Memory: 16 MB (128 Mb)

Pin Assignments

 Name Pin
LED GPIO0
DATA GPIO1
DATA2* GPIO28
KEY0 GPIO2
KEY1 GPIO3
KEY2 GPIO4
KEY3 GPIO5
KEY4 GPIO6
KEY5 GPIO7
KEY6 GPIO8
KEY7 GPIO9
KEY8 GPIO10
KEY9 GPIO11
KEY10 GPIO12
KEY11 GPIO13
KEY12 GPIO14
KEY13 GPIO15
KEY14 GPIO16
KEY15 GPIO17
KEY16 GPIO18
KEY17 GPIO19
KEY18** GPIO20
KEY19** GPIO21
KEY20** GPIO22
SDA GPIO24
SCL GPIO25

* Not connected on mini42 prototype units

** Not connected on mini36

Warnings

  • The OLED screen on the keyboard is delicate. Do not apply pressure to the screens during handling.
  • The Kailh Chocolate hot swap sockets are only rated for 100 switch installations. Some switch installation cycles were done during initial testing of the keyboard. Only swap switches when you are sure you want to change switches in order to avoid unnecessary wear on the hot swap socket contacts.
  • There is circuit protection on the TRRS and USB connectors. However, improperly inserting the audio cable in the TRRS socket is still not recommended. Please make sure the cable connector is seated all the way in the socket before plugging in the USB for power.