KeyboardMessage.ino

/*
  Keyboard Message test

  For STM32 based board with USB capabilities

  Sends a text string when a button is pressed.

  The circuit:
  - pushbutton attached from pin 4 to +3.3V
  - 10 kilohm resistor attached from pin 4 to ground

  created 24 Oct 2011
  modified 27 Mar 2012
  by Tom Igoe
  modified 11 Nov 2013
  by Scott Fitzgerald

  This example code is in the public domain.

  https://www.arduino.cc/en/Tutorial/BuiltInExamples/KeyboardMessage
*/

#include "Keyboard.h"

#ifdef USER_BTN
const int buttonPin = USER_BTN;          // input pin for pushbutton
#else
const int buttonPin = 4;          // input pin for pushbutton
#endif

int previousButtonState = HIGH;   // for checking the state of a pushButton
int counter = 0;                  // button push counter

void setup() {
  // make the pushButton pin an input:
  pinMode(buttonPin, INPUT);
  // initialize control over the keyboard:
  Keyboard.begin();
}

void loop() {
  // read the pushbutton:
  int buttonState = digitalRead(buttonPin);
  // if the button state has changed,
  if ((buttonState != previousButtonState)
      // and it's currently pressed:
      && (buttonState == HIGH)) {
    // increment the button counter
    counter++;
    // type out a message
    Keyboard.print("You pressed the button ");
    Keyboard.print(counter);
    Keyboard.println(" times.");
  }
  // save the current button state for comparison next time:
  previousButtonState = buttonState;
}