#define AnalogLDR A0
#define Limiar 1.5 
#define ledPin 13
int Leitura = 0;
float VoltageLDR;
float ResLDR; 

void setup()
{
pinMode(ledPin, OUTPUT);
Serial.begin(9600); 
delay(100); 
} 

void loop()
{
Leitura = analogRead(AnalogLDR);
VoltageLDR = Leitura * (5.0/1024);
Serial.print("Leitura sensor LDR =") ;
Serial.println(VoltageLDR);
if (VoltageLDR > Limiar) 
digitalWrite(ledPin, HIGH); 
else 
digitalWrite(ledPin, LOW); 
delay(500); 
}