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James Young 292b7b3835
Remove firmware size impact notes from <keyboard>/ (#14652)
9 months ago
keymaps [Keyboard] add info.json for dactyl_promicro (#6993) 2 years ago
config.h Remove `DESCRIPTION`, H-J (#11616) 1 year ago
dactyl_promicro.c Remove empty override functions (#14312) 9 months ago
dactyl_promicro.h [Keyboard] add info.json for dactyl_promicro (#6993) 2 years ago
info.json Remove width, height and key_count from info.json (#14274) 9 months ago [Keyboard] handwired dactyl with 2 pro micros added (#5113) 3 years ago Remove firmware size impact notes from <keyboard>/ (#14652) 9 months ago

Dactyl with Arduino Pro Micro

See for the original Version.

This Dactyl uses the Arduino Pro Mirco (2x). Wiring is a 6x6 Matrix like the Dactyl Manuform

Build the Firmware:

  • Build the firmware with make handwired/dactyl_promicro:<keymapname>, for example make handwired/dactyl:default
  • This will result in a hex file called handwired_dactyl_promicro_<keymapname>.hex, e.g. handwired_dactyl_promicro_default.hex

How to setup your build enviroment can be found here: Installing Build Tools

Required Hardware

Apart from diodes and key switches for the keyboard matrix in each half, you will need:

  • 2 Arduino Pro Micros. You can find these on AliExpress for ≈3.50USD each.
  • 2 TRRS sockets and 1 TRRS cable, or 2 TRS sockets and 1 TRS cable

Alternatively, you can use any sort of cable and socket that has at least 3 wires. If you want to use I2C to communicate between halves, you will need a cable with at least 4 wires and 2x 4.7kΩ pull-up resistors

Optional Hardware

A speaker can be hooked-up to either side to the 5 (C6) pin and GND, and turned on via AUDIO_ENABLE.


The 3 wires of the TRS/TRRS cable need to connect GND, VCC, and digital pin 3 (i.e. PD0 on the ATmega32u4) between the two Pro Micros.

Next, wire your key matrix to any of the remaining 17 IO pins of the pro micro and modify the matrix.c accordingly.

The wiring for serial:

serial wiring

The wiring for i2c:

i2c wiring

The pull-up resistors may be placed on either half. It is also possible to use 4 resistors and have the pull-ups in both halves, but this is unnecessary in simple use cases.

You can change your configuration between serial and i2c by modifying your config.h file.

Notes on Software Configuration

the keymaps in here are for the 4x5 layout of the keyboard only.


To flash your firmware take a look at: Flashing Instructions and Bootloader Information.

Under Windows the most convenient way is installing the QMK Drivers and use the QMK Toolbox.

Choosing which board to plug the USB cable into (choosing Master)

Setting the right or left hand as master

If you always plug the usb cable into the right board, add an extra flag to your config.h



 #define MASTER_LEFT

Notes on Using Pro Micro 3.3V

Do update the F_CPU parameter in to 8000000 which reflects the frequency on the 3.3V board.

Also, if the slave board is producing weird characters in certain columns, update the following line in matrix.c to the following:

// _delay_us(30);  // without this wait read unstable value.
_delay_us(300);  // without this wait read unstable value.