/* led comme capteur de lumière
 * led blanche/infrarouge -> A0(+) -> GND
 * led verte -> 13(+) -> GND
 */

int LED_DISPLAY = 13;
int LED_ACQUIRE = 0;
int THRESHOLD = 110; 

int value = 0;

void setup()
{
  Serial.begin(9600);
  pinMode(LED_DISPLAY, OUTPUT);
}

void loop()
{
   value = analogRead(LED_ACQUIRE);
   Serial.println(value);
    
    if (value < THRESHOLD) // pas de lumière
      digitalWrite(LED_DISPLAY, HIGH); // allumer la led
    else
      digitalWrite(LED_DISPLAY, LOW); // éteindre la led
}