https://github.com/dhruvinsh/zmk-tri-state
Proof of concept where swapper implemented as external module
https://github.com/dhruvinsh/zmk-tri-state
zephyr zmk zmk-config zmk-firmware
Last synced: about 2 months ago
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Proof of concept where swapper implemented as external module
- Host: GitHub
- URL: https://github.com/dhruvinsh/zmk-tri-state
- Owner: dhruvinsh
- Created: 2024-02-03T22:22:38.000Z (over 2 years ago)
- Default Branch: main
- Last Pushed: 2025-03-16T19:01:18.000Z (about 1 year ago)
- Last Synced: 2026-01-24T07:08:51.935Z (4 months ago)
- Topics: zephyr, zmk, zmk-config, zmk-firmware
- Language: C
- Homepage:
- Size: 24.4 KB
- Stars: 18
- Watchers: 1
- Forks: 14
- Open Issues: 2
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
- awesome-zmk - dhruvinsh/zmk-tri-state - Tri-state (swapper) implementation. (Community firmware Modules and Behaviors / Custom Behaviors)
- awesome-zmk - dhruvinsh/zmk-tri-state - Tri-state (swapper) implementation. (Behaviors)
README
# ZMK-TRI-STATE
A ZMK implementation of [Nick Conway's](https://github.com/nickconway) tri-state behavior for the
[ZMK Firmware](https://github.com/zmkfirmware/zmk).
This project demonstrates how to implement custom behaviors without maintaining
a separate ZMK fork. It's fully compatible with the latest Zephyr 3.5 release.
## Installation
Add this module to your ZMK config by modifying your `config/west.yml` file. Add
the necessary `remotes` and `projects` sections as shown below:
```yaml
manifest:
remotes:
- name: zmkfirmware
url-base: https://github.com/zmkfirmware
- name: dhruvinsh
url-base: https://github.com/dhruvinsh
projects:
- name: zmk
remote: zmkfirmware
revision: main
import: app/west.yml
- name: zmk-tri-state
remote: dhruvinsh
revision: main
self:
path: config
```
For a complete example configuration, see [my ZMK config](https://github.com/dhruvinsh/zmk-config/blob/0e4919ba45f08714bf1cc053c103ae1977bacd76/config/west.yml).
**NOTE: Common use-cases have not yet been defined for this behavior in the DTSI format. See [ZMK documentation](https://zmk.dev/docs/development/new-behavior#defining-common-use-cases-for-the-behavior-dtsi-optional) for more information.**
## Basic Usage
Add the tri-state behavior to your keymap:
```devicetree
#include
/ {
behaviors {
swapper: swapper {
compatible = "zmk,behavior-tri-state";
#binding-cells = <0>;
bindings = <&kp A>, <&kp B>, <&kt C>;
};
};
};
```
After defining it, you can use `&swapper` anywhere in your keymap. See the detailed documentation below for more information and check out a [working example here](https://github.com/dhruvinsh/zmk-config/blob/0ed6b525a5834dc423eb600b4552b9afb9c621ee/config/include/behaviors.dtsi#L52-L61).
## Summary: Tri-State
Tri-States are a way to have something persist while other behaviors occur.
The tri-state key will fire the 'start' behavior when the key is pressed for
the first time. Subsequent presses of the same key will output the second,
'continue' behavior, and any key position or layer state change that is not
specified (see below) will trigger the 'interrupt behavior'.
### Basic Usage
The following is a basic definition of a tri-state:
```devicetree
/ {
behaviors {
tri-state: tri-state {
compatible = "zmk,behavior-tri-state";
label = "TRI-STATE";
#binding-cells = <0>;
bindings = <&kp A>, <&kp B>, <&kt C>;
};
};
keymap {
compatible = "zmk,keymap";
label ="Default keymap";
default_layer {
bindings = <
&tri-state &kp D
&kp E &kp F>;
};
};
};
```
Pressing `tri-state` will fire the first behavior, and output `A`, as well as
the second behavior, outputting `B`. Subsequent presses of `tri-state` will
output `B`. When another key is pressed or a layer change occurs, the third,
'interrupt' behavior will fire.
### Advanced Configuration
#### `timeout-ms`
Setting `timeout-ms` will cause the deactivation behavior to fire when the time
has elapsed after releasing the Tri-State or a ignored key.
#### `ignored-key-positions`
- Including `ignored-key-positions` in your tri-state definition will let the
key positions specified NOT trigger the interrupt behavior when a tri-state
is active.
- Pressing any key **NOT** listed in `ignored-key-positions` will cause the
interrupt behavior to fire.
- Note that `ignored-key-positions` is an array of key position indexes. Key
positions are numbered according to your keymap, starting with 0. So if the
first key in your keymap is Q, this key is in position 0. The next key
(probably W) will be in position 1, et cetera.
- See the following example, which is an implementation of the popular [Swapper](https://github.com/callum-oakley/qmk_firmware/tree/master/users/callum)
from Callum Oakley:
```devicetree
/ {
behaviors {
swap: swapper {
compatible = "zmk,behavior-tri-state";
label = "SWAPPER";
#binding-cells = <0>;
bindings = <&kt LALT>, <&kp TAB>, <&kt LALT>;
ignored-key-positions = <1>;
};
};
keymap {
compatible = "zmk,keymap";
label ="Default keymap";
default_layer {
bindings = <
&swap &kp LS(TAB)
&kp B &kp C>;
};
};
};
```
- The sequence `(swap, swap, LS(TAB))` produces `(LA(TAB), LA(TAB), LA(LS(TAB)))`.
The LS(TAB) behavior does not fire the interrupt behavior, because it is
included in `ignored-key-positions`.
- The sequence `(swap, swap, B)` produces `(LA(TAB), LA(TAB), B)`. The B
behavior **does** fire the interrupt behavior, because it is **not** included
in `ignored-key-positions`.
#### `ignored-layers`
- By default, any layer change will trigger the end behavior.
- Including `ignored-layers` in your tri-state definition will let the specified
layers NOT trigger the end behavior when they become active (include the
layer the behavior is on to accommodate for layer toggling).
- Activating any layer **NOT** listed in `ignored-layers` will cause the
interrupt behavior to fire.
- Note that `ignored-layers` is an array of layer indexes. Layers are numbered
according to your keymap, starting with 0. The first layer in your keymap is
layer 0. The next layer will be layer 1, et cetera.
- Looking back at the swapper implementation, we can see how `ignored-layers`
can affect things
```devicetree
/ {
behaviors {
swap: swapper {
compatible = "zmk,behavior-tri-state";
label = "SWAPPER";
#binding-cells = <0>;
bindings = <&kt LALT>, <&kp TAB>, <&kt LALT>;
ignored-key-positions = <1 2 3>;
ignored-layers = <1>;
};
};
keymap {
compatible = "zmk,keymap";
label ="Default keymap";
default_layer {
bindings = <
&swap &kp LS(TAB)
&kp B &tog 1>;
};
layer2 {
bindings = <
&kp DOWN &kp B
&tog 2 &trans>;
};
layer3 {
bindings = <
&kp LEFT &kp N2
&trans &kp N3>;
};
};
};
```
- The sequence `(swap, tog 1, DOWN)` produces `(LA(TAB), LA(DOWN))`. The change
to layer 1 does not fire the interrupt behavior, because it is included in
`ignored-layers`, and DOWN is in the same position as the tri-state, also not
firing the interrupt behavior.
- The sequence `(swap, tog 1, tog 2, LEFT)` produces `(LA(TAB), LEFT`. The
change to layer 2 **does** fire the interrupt behavior, because it is not
included in `ignored-layers`.
## Credits
- [Pete Johanson](https://github.com/petejohanson)
- [Nick Conway](https://github.com/nickconway)
- [Cem Aksoylar](https://github.com/caksoylar)
- ZMK and Zephyr Teams
## Related Projects
- [ZMK-NUM-WORD](https://github.com/dhruvinsh/zmk-num-word)