#include "OneButton.h"

OneButton button1( 5 );
const uint8_t ledPin = LED_BUILTIN;

void toggleLED()
{
  static bool state = false;
  state = !state;
  digitalWrite( ledPin, state == true ? HIGH : LOW );
  Serial.print( "LED is " );
  Serial.println( state == true ? "ON" : "OFF" );
}

void button1LongPress()
{
  toggleLED(); // invert the state of the LED
}

void setup()
{
  Serial.begin( 115200 );
  pinMode( ledPin, OUTPUT );
  toggleLED(); // turn on the LED

  button1.setPressTicks( 2500 ); // a long press will be detected after 2500 ms
  button1.attachLongPressStart( button1LongPress ); // function to be called once, while the button is pressed
  //button1.attachLongPressStop( button1LongPress ); // function to be called when the button was released
}

void loop()
{
  button1.tick();
}