// Photoresistors | Light Dependent Resistors
int LED = 13;
int LDRpin = A0;

void setup(){
  // put your setup code here, to run once:
  pinMode(LED, OUTPUT);
  pinMode(LDRpin, INPUT);
  Serial.begin(9600); 
}

void loop(){  
  // put your main code here, to run repeatedly:
  int sensorValue = analogRead(LDRpin);
  
  //lux, unit of illumination (see luminous intensity) in the International System of Units (SI).
  if(sensorValue <= 40){ // compare sensorThreshhold value  	
    Serial.print("light source and the area luminous power(lux) is very low : ");
    Serial.println(sensorValue);
    digitalWrite(LED, HIGH);
       
  }
  else{  	
    Serial.print("The area luminous power(lux) is :  ");
    Serial.println(sensorValue);
    digitalWrite(LED, LOW);  
  }
  delay(1000); // Wait for 1000 millisecond(s)
}