Existing support for encoders in ZMK is focused around the five pin EC11 rotary encoder with push button design used in the majority of current keyboard and macropad designs.
Enabling EC11 Encoders
To enable encoders for boards that have existing encoder support, uncomment the
CONFIG_EC11_TRIGGER_GLOBAL_THREAD=y lines in your board's .conf file in your
zmk-config/config folder. Save and push your changes, then download and flash the new firmware.
Customizing EC11 Encoder Behavior
Encoder behavior in ZMK is configured in two different locations as the push button and rotation behaviors are handled in two separate ways.
Keyboards and macropads with encoder support will typically take the two EC11 pins responsible for the push button and include them as part of the matrix for the keys. To configure what is sent by the push button, find the encoder's position in the keyboard matrix and assign it a behavior the same as you would any other key.
Rotation is handled separately as a type of sensor. The behavior for this is set in
sensor-bindings, which is defined in each keymap layer in the following format:
BINDINGis one of two rotation bindings that are currently defined,
&inc_dec_cpfor consumer key presses or
&inc_dec_kpfor normal key presses (see Key Press for the difference between the two).
CW_KEYis the keycode activated by a clockwise turn.
CCW_KEYis the keycode activated by a counter-clockwise turn.
Additional encoders can be configured by adding more
BINDING CW_KEY CCW_KEY sets immediately after the first.
As an example, a complete
sensor-bindings for a Kyria with two encoders could look like:
Here, the left encoder is configured to control volume up and down while the right encoder sends either Page Up or Page Down.
Adding Encoder Support
See the New Keyboard Shield documentation for how to add or modify additional encoders to your shield.