int ldrPin = A0;  // A0
int ldrValue = 0; // 
int relay = 7;
void setup() {
  Serial.begin(9600);   
  pinMode(ldrPin, INPUT);
  pinMode(relay, OUTPUT);

}

void loop() {
  ldrValue = analogRead(ldrPin); 
  Serial.print("LDR Value: ");    
  Serial.println(ldrValue);  

   // Light/Dark detection threshold
  if (ldrValue > 500) {
    Serial.println(" --> Light Detected ☀");
    digitalWrite(relay, LOW);
  } else {
    Serial.println(" --> Dark Detected 🌙");
    digitalWrite(relay, HIGH);
  }
  delay(500);                     
}