// Pin assignments
const int pirPin = 2;      // PIR sensor output pin
const int ldrPin = A0;     // LDR analog input pin
const int relayPin = 5;    // Relay Pin

// Threshold values
int ldrThreshold = 300;    // Threshold for the LDR

int pirState = LOW;        // Initial state of PIR sensor
int pirValue = 0;          // PIR sensor value

void setup() {
  pinMode(pirPin, INPUT);      // PIR sensor as input
  pinMode(relayPin, OUTPUT);   // Relay as output
  Serial.begin(9600);          // Initialize serial communication
}

void loop() {
  // Read PIR sensor value
  pirValue = digitalRead(pirPin);
  
  // Read LDR value (light level)
  int ldrValue = analogRead(ldrPin);
  
  // Print LDR and PIR values (for debugging)
  Serial.print("LDR Value: "+String(ldrValue));
  Serial.print(" | PIR Value: "+String(pirValue));

  // If PIR detects motion and ambient light level is low, turn on the Relay
  if (pirValue == HIGH && ldrValue < ldrThreshold) {
    digitalWrite(relayPin, HIGH);  // Turn on the Relay
    Serial.println(" | RELAY ON");
  } 
  // If no motion or ambient light is high, turn off the Relay
  else {
    digitalWrite(relayPin, LOW);   // Turn off the Relay
    Serial.println(" | RELAY OFF");
  }
  delay(500);  // Short delay to avoid bouncing
}