int Sensor_LDR;
int pin_LDR = A0;
int pin_LED = 5;

void setup() {
 Serial.begin(9600);
 pinMode(pin_LED, OUTPUT);
 pinMode(pin_LDR, INPUT);

}

void loop() {
 Sensor_LDR = analogRead(pin_LDR);
 Serial.print("valor lido");
 Serial.println(Sensor_LDR);

 delay(500);
 if (Sensor_LDR > 800){
  digitalWrite(pin_LED, HIGH);
 } else {
  digitalWrite(pin_LED, LOW);
 }
}