// ldr_smart_lighting.ino 
// Photocell LED control

//set pin numbers
const int ledPin = 13;   //the number of the LED pin
const int ldrPin = A0;  //the number of the LDR pin

int threshold = 300;  // LED trigger value
  
void setup() { 
  Serial.begin(9600);
  pinMode(ledPin, OUTPUT);  //initialize the LED pin as an output
  pinMode(ldrPin, INPUT);   //initialize the LDR pin as an input
}
 
void loop() {
  int ldrStatus = analogRead(ldrPin);   //read the status of the LDR value  
  Serial.print("LDR value is ");
  Serial.print(ldrStatus);
  Serial.print("  Trigger value is ");
  Serial.println(threshold);
  if (ldrStatus <= threshold) { //check if the LDR status is <= threshold, then set LED HIGH
    digitalWrite(ledPin, HIGH);               //turn LED on
    Serial.println("Now is DARK, turn LED ON");     
  }
  else { 
    digitalWrite(ledPin, LOW);          //turn LED off
    Serial.println("---------------");
  }
  delay(1000);
}