RGB Underglow Configuration

See the RGB Underglow feature page for more details, including instructions for adding underglow support to a board.

See Configuration Overview for instructions on how to change these settings.

Kconfig

RGB underglow depends on Zephyr's LED strip driver, which provides additional Kconfig options.

Definition file: zmk/app/Kconfig

Config	Type	Description	Default
CONFIG_ZMK_RGB_UNDERGLOW	bool	Enable RGB underglow	n
CONFIG_ZMK_RGB_UNDERGLOW_EXT_POWER	bool	Underglow toggling also controls external power	y
CONFIG_ZMK_RGB_UNDERGLOW_AUTO_OFF_IDLE	bool	Turn off RGB underglow when keyboard goes into idle state	n
CONFIG_ZMK_RGB_UNDERGLOW_AUTO_OFF_USB	bool	Turn off RGB underglow when USB is disconnected	n
CONFIG_ZMK_RGB_UNDERGLOW_HUE_STEP	int	Hue step in degrees (0-359) used by RGB actions	10
CONFIG_ZMK_RGB_UNDERGLOW_SAT_STEP	int	Saturation step in percent used by RGB actions	10
CONFIG_ZMK_RGB_UNDERGLOW_BRT_STEP	int	Brightness step in percent used by RGB actions	10
CONFIG_ZMK_RGB_UNDERGLOW_HUE_START	int	Default hue in degrees (0-359)	0
CONFIG_ZMK_RGB_UNDERGLOW_SAT_START	int	Default saturation percent (0-100)	100
CONFIG_ZMK_RGB_UNDERGLOW_BRT_START	int	Default brightness in percent (0-100)	100
CONFIG_ZMK_RGB_UNDERGLOW_SPD_START	int	Default effect speed (1-5)	3
CONFIG_ZMK_RGB_UNDERGLOW_EFF_START	int	Default effect index from the effect list (see below)	0
CONFIG_ZMK_RGB_UNDERGLOW_ON_START	bool	Default on state	y

Values for CONFIG_ZMK_RGB_UNDERGLOW_EFF_START:

Value	Effect
0	Solid color
1	Breathe
2	Spectrum
3	Swirl

note

The *_START settings only determine the initial underglow state. Any changes you make with the underglow behavior are saved to flash after a one minute delay and will be used after that.

Devicetree

ZMK does not have any Devicetree properties of its own. See the Devicetree bindings for Zephyr's LED strip drivers.

See the RGB underglow feature page for examples of the properties that must be set to enable underglow.