int sensor= A2;
int sensorLecture= 0;
int LED= D7; 
int a=0;
int b=0;

void setup() {
  Serial.begin (9600);
  pinMode(sensor, INPUT);
  pinMode(LED, OUTPUT);
}

void loop() {
  sensorLecture=digitalRead(sensor);
  if (sensorLecture == HIGH)
  {
    a=a+1;
    b=0;
    delay (200);
  }

  if (a == 1 && b == 0)
  {
    digitalWrite(LED, HIGH);
    Serial.println("ON");
    b=1;
  }
  if (a == 2)
  {
    digitalWrite(LED, LOW);
   Serial.println("OFF");
    a=0;
  }
}