// constants won't change. Used here to set a pin number:
const int ledPin = LED_BUILTIN;  // the number of the LED pin

// Variables will change:
int ledState = LOW;  // ledState used to set the LED

// Generally, you should use "unsigned long" for variables that hold time
// The value will quickly become too large for an int to store
unsigned long previousMillis = 0;  // will store last time LED was updated
unsigned long myTime;

// constants won't change:
const long interval = 1000;  // interval at which to blink (milliseconds)




void setup() {
  // put your setup code here, to run once:
  //  pinMode(LED_BUILTIN, OUTPUT);
  Serial.begin(9600);
  // set the digital pin as output:
  pinMode(ledPin, OUTPUT);
}

void loop() {
  unsigned long currentMillis = millis();

  if (currentMillis - previousMillis >= interval) {
    // save the last time you blinked the LED
    previousMillis = currentMillis;

    // if the LED is off turn it on and vice-versa:
    if (ledState == LOW) {
      ledState = HIGH;
    } else {
      ledState = LOW;
    }

    // set the LED with the ledState of the variable:
    digitalWrite(ledPin, ledState);
  }
  
  // afficher valeurs de la fonction millis()
  Serial.print("Time: ");
  myTime = millis();
  Serial.println(myTime); // prints time since program started
  delay(1000);          // wait a second so as not to send massive amounts of data
}

/* BLINK with use of delay() function :

  // put your main code here, to run repeatedly:
  digitalWrite(LED_BUILTIN, HIGH);
  delay(1000);
  digitalWrite(LED_BUILTIN, LOW);
  delay(1000);

  Serial.print("Time: ");
  myTime = millis();

  Serial.println(myTime); // prints time since program started
  delay(1000);          // wait a second so as not to send massive amounts of data

  // check to see if it's time to blink the LED; that is, if the difference
  // between the current time and last time you blinked the LED is bigger than
  // the interval at which you want to blink the LED.
*/