Keyboard Modifiers and Special Keys

Description

When given a printable ASCII character as an argument, the functions Keyboard.write(), Keyboard.press() and Keyboard.release() simulate actuations on the corresponding keys. These functions can also handle ASCII characters that require pressing a key in combination with Shift or, on international keyboards, AltGr. For example:

Keyboard.write('a');  // press and release the 'A' key
Keyboard.write('A');  // press Shift and 'A', then release both

A typical keyboard, however, has many keys that do not match a printable ASCII character. In order to simulate those keys, the library provides a set of macros that can be passed as arguments to Keyboard.write(), Keyboard.press() and Keyboard.release(). For example, the key combination Shift+F2 can be generated by:

Keyboard.press(KEY_LEFT_SHIFT);  // press and hold Shift
Keyboard.press(KEY_F2);          // press and hold F2
Keyboard.releaseAll();           // release both

Note that, in order to press multiple keys simultaneously, one has to use Keyboard.press() rather than Keyboard.write(), as the latter just “hits” the keys (it presses and immediately releases them).

The available macros are listed below:

Keyboard modifiers

These keys are meant to modify the normal action of another key when the two are pressed in combination.

Special keys

These are all the keys that do not match a printable ASCII character and are not modifiers.

Within the alphanumeric cluster

Navigation cluster

Numeric keypad

Escape and function keys

The library can simulate function keys up to F24.

Function control keys

These are three keys that sit above the navigation cluster.

International keyboard layouts

Some national layouts define extra keys. For example, the Swedish and Danish layouts define KEY_A_RING as 0xB7, which is the key to the right of “P”, labeled “Å” on those layouts and “{”/“[” on the US layout. In order to use those definitions, one has to include the proper Keyboard_*.h file. For example:

#include <Keyboard.h>
#include <Keyboard_sv_SE.h> // extra key definitions from Swedish layout

void setup() {
  Keyboard.begin(KeyboardLayout_sv_SE); // use the Swedish layout
  Keyboard.write(KEY_A_RING);
}

void loop() {} // do-nothing loop

For the list of layout-specific key definitions, see the respective Keyboard_*.h file within the library sources.