Disclaimer

• Fork of: https://github.com/Keychron/qmk_firmware.
• Use at Your Own Risk: Proceed with caution. Consult the documentation and recommendations of the manufacturers.
• VIA Compatibility: Using this custom QMK firmware will disable direct adjustments with VIA.
• Keymap Adjustment: The keymap has been specifically adjusted for the Keychron Q5 Max, but many changes may be adaptable to other keyboards.

Functionalities

• Umlauts on Q5 Max ANSI Layout: Outputs German umlauts (äöü) using the standard US layout on Windows, without needing the US international layout.
• LED Color Customization: Changes the LED color of all customized keys when switching layers.
• Shift Key Behavior: Double-tapping the Shift key activates Caps Lock.
• TAP Hold for Umlauts: Holding down the Umlaut key (250ms) outputs the original key (i.E ä -> ') without having to switching back to the base layer while being in "writing" mode.

For detailed changes, refer to the comments in Keymap.c.

Firmware modifications

• Keymap.c
• Rules.mk

Prerequisites

• QMK MSYS: Ensure QMK MSYS is installed on your system.

Clone the Repository:

git clone https://github.com/astro-phage/qmk_firmware.git
git checkout wireless_playground

The branch wireless_playground contains keymaps for Keychron's wireless keyboards and therefore the modifications.

Build and Flash Firmware:

Open QMK MSYS and navigate to the qmk_firmware directory. Run the following command:

make keychron/q5_max/ansi_encoder:default:flash

Enter Flash Mode: Unplug the keyboard and then plug it back in while holding the key.

Why Not US-International Layout?

Alternatively, you could use the US-International layout with an ANSI keyboard and type umlauts using key combinations like RALT + P for ö. For more information, see this Reddit post. However, this approach has some drawbacks. It includes dead keys, and for example, pressing the quote key may produce two quote, which can be particularly annoying, especially for coding. Instead, you can use alt codes (see Alt-Codes) to type umlauts while using the standard US layout.

Notes

The current code is a quick solution and may require significant refactoring. It is provided in its current state to assist with creating your own custom keymap. Partial code adaptations are from: https://gist.github.com/itspngu/9159f06153b440a754b33c6d65c5f302