Born out of the desire to demo LED effects on the keyboard without having to touch it by hand (which would obstruct the video), the GhostInTheFirmware plugin allows one to inject events at various delays, by telling it which keys to press. Unlike macros, these press keys at given positions, as if they were pressed by someone typing on it - the firmware will not see the difference.

Given a sequence (with press- and delay times), the plugin will walk through it once activated, and hold the key for the specified amount, release it, and move on to the next after the delay time.

Using the plugin

To use the plugin, one needs to include the header, and configure it with a list of key coordinates, a press time, and a delay time quartett. One also needs a way to trigger starting the sequence, and a macro is the most convenient way for that.

#include <Kaleidoscope.h>
#include <Kaleidoscope-GhostInTheFirmware.h>
#include <Kaleidoscope-Macros.h>

const macro_t *macroAction(uint8_t macro_id, KeyEvent& event) {
  if (macro_id == 0 && keyToggledOn(event.state))

  return MACRO_NONE;

static const kaleidoscope::plugin::GhostInTheFirmware::GhostKey ghost_keys[] PROGMEM = {
  {KeyAddr(0, 0), 200, 50},
  {KeyAddr::none(), 0, 0}


void setup() {
  Kaleidoscope.setup ();

  GhostInTheFirmware.ghost_keys = ghost_keys;

The plugin won’t be doing anything until its activate() method is called - hence the macro.

Plugin methods

The plugin provides the GhostInTheFirmware object, which has the following methods and properties:


Start playing back the sequence. Best called from a macro.


Set this property to the sequence of keys to press, by assigning a sequence to this variable. Each element is a GhostKey object, comprised of a KeyAddr (the location of a key on the keyboard), a duration of the key press (in milliseconds), and a delay after the key release until the next one is pressed (also in milliseconds).

This ghost_keys array MUST end with the sentinal value of {KeyAddr::none(), 0, 0} to ensure that GhostInTheFirmware doesn’t read past the end of the array.

The sequence MUST reside in PROGMEM.

Further reading

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