int Sensor_LDR;
int Pin_LDR = A0;
int led=2;

void setup() {
Serial.begin(9600);
pinMode(led, OUTPUT);
pinMode(Pin_LDR, INPUT);
}

void loop() {
  Sensor_LDR = digitalRead(Pin_LDR);

Serial.print("Valor lido: ");
delay(100);

if (Sensor_LDR == 1) {
digitalWrite(led, HIGH);
Serial.println("Nao tem luz");
}
else {
digitalWrite(led, LOW);
Serial.println("Tem luz");
}
}