int led = 4;
int sensor = 2;
int estado = 0;

void setup() {
  // put your setup code here, to run once:
  pinMode(led, OUTPUT);
  pinMode(sensor, INPUT);


}

void loop() {
  // put your main code here, to run repeatedly:
  estado  = digitalRead(sensor);

  if(estado == 0){
    digitalWrite(led, HIGH);
  }
  else {
    digitalWrite(led, LOW);
  }

}