const int pirPin = 2;      
const int relayPin = 7;    

void setup() {
  pinMode(pirPin, INPUT);   
  pinMode(relayPin, OUTPUT); 
  digitalWrite(relayPin, LOW); 
  Serial.begin(9600);
}

void loop() {
  int pirState = digitalRead(pirPin);
  
  if (pirState == HIGH) { 
    digitalWrite(relayPin, HIGH); 
    Serial.println("Motion detected! Relay ON.");
  } else {  
    digitalWrite(relayPin, LOW);   
    Serial.println("No motion detected. Relay OFF.");
  }
  delay(100);
}