Plugin to add "tappable" sticky modifiers and layers for Kaleidoscope.
Switch branches/tags
Nothing to show
Clone or download
algernon & Travis cleanup
Remove the IRC notifications from Travis (we're not using IRC anymore), and the
stable/experimental badge from (because they aren't being kept up to date).

Signed-off-by: Gergely Nagy <>
Latest commit 9a08f88 Oct 9, 2018


Build Status

One-shots are a new kind of behaviour for your standard modifier and momentary layer keys: instead of having to hold them while pressing other keys, they can be tapped and released, and will remain active until any other key is pressed. In short, they turn Shift, A into Shift+A, and Fn, 1 to Fn+1. The main advantage is that this allows us to place the modifiers and layer keys to positions that would otherwise be awkward when chording. Nevertheless, they still act as normal when held, that behaviour is not lost.

Furthermore, if a one-shot key is tapped two times in quick succession, it becomes sticky, and remains active until disabled with a third tap. This can be useful when one needs to input a number of keys with the modifier or layer active, and still does not wish to hold the key down. If this feature is undesirable, unset the OneShot.double_tap_sticky property (see later).

To make multi-modifier, or multi-layer shortcuts possible, one-shot keys remain active if another one-shot of the same type is tapped, so Ctrl, Alt, b becomes Ctrl+Alt+b, and L1, L2, c is turned into L1+L2+c. Furthermore, modifiers and other layer keys do not cancel the one-shot effect, either.

Using One-Shot Keys

To enter one-shot mode, tap quickly on a one-shot key. The next normal (non-one-shot) key you press will have the modifier applied, and then the modifier will automatically turn off. If the Shift key is a one-shot modifier, then hitting Shift, a, b will give you Ab, if you hit shift quickly.

Longish keypresses do not activate one-shot mode. If you press Shift, a, b, as above, but hold the Shift key a bit longer, you'll get ab.

To enter sticky mode, tap twice quickly on a one-shot key. The modifier will now stay on until you press it again. Continuing the Shift example, tapping Shift, Shift quickly and then a, b, c, Shift, d, e, f will give you ABCdef.

This can be a bit tricky; combining this plugin with LED-ActiveModColor will help you understand what state your one-shot is in; when a one-shot key is active, it will have a white LED highlight; when sticky, a red highlight.

Using the plugin

After adding one-shot keys to the keymap, all one needs to do, is enable the plugin:

#include <Kaleidoscope.h>
#include <Kaleidoscope-OneShot.h>
#include <kaleidoscope/hid.h>

// somewhere in the keymap...
OSM(LeftControl), OSL(_FN)


void setup() {

Keymap markup

There are two macros the plugin provides:


A macro that takes a single argument, the name of the modifier: LeftControl, LeftShift, LeftAlt, LeftGui or their right-side variant. When marked up with this macro, the modifier will act as a one-shot modifier.


Takes a layer number as argument, and sets up the key to act as a one-shot layer key.

Please note that while Kaleidoscope supports more, one-shot layers are limited to 8 layers only.

Plugin methods

The plugin provides one object, OneShot, which implements both one-shot modifiers and one-shot layer keys. It has the following methods:


Returns if any one-shot key is in flight. This makes it possible to differentiate between having a modifier or layer active, versus having them active only until after the next key getting pressed. And this, in turn, is useful for macros that need to fiddle with either modifier or layer state: if one-shots are not active, they need not restore the original state.


Returns true if any one-shot key is still held.


Returns if the key is currently sticky.


Returns if the modifier key has a one-shot state active. Use this together with hid::isModifierKeyActive to catch cases where a one-shot modifier is active, but not registered yet.


The cancel() method can be used to cancel any pending one-shot effects, useful when one changed their minds, and does not wish to wait for the timeout.

The optional with_stickies argument, if set to true, will also cancel sticky one-shot effects. If omitted, it defaults to false, and not canceling stickies.

.inject(key, keyState)

Simulates a key event, specifically designed to inject one-shot keys into the event loop. The primary purpose of this method is to make it easier to trigger multiple one-shots at the same time.

See the example sketch for more information about its use.

Plugin properties

Along with the methods listed above, the OneShot object has the following properties too:


Set this property to the number of milliseconds to wait before timing out and cancelling the one-shot effect (unless interrupted or cancelled before by any other means).

Defaults to 2500.


Set this property to the number of milliseconds to wait before considering a held one-shot key as intentionally held. In this case, the one-shot effect will not trigger when the key is released. In other words, holding a one-shot key at least this long, and then releasing it, will not trigger the one-shot effect.

Defaults to 200.


Set this boolean property to make the plugin treat a double-tap of a one-shot key as making it sticky until a third tap. Setting it to false disables this behaviour, in which case double-tapping a one-shot modifier will just restart the timer.

Defaults to true.


The same as .double_tap_sticky, but only applies to layers. The two can be set separately.

Defaults to true.


Set this property to the number of milliseconds within which a second uninterrupted tap of the same one-shot key will be treated as a sticky-tap. Only takes effect when .double_tap_sticky is set.

Setting the property to -1 will make the double-tap timeout use .time_out for its calculations.

Defaults to -1.


Further reading

Starting from the example is the recommended way of getting started with the plugin.