// Relay pin
const int relayPin = 7;

void setup() {
  pinMode(relayPin, OUTPUT); // Set pin 7 as output
}

void loop() {
  digitalWrite(relayPin, HIGH); // Turn relay ON
  delay(5000);                   // Wait 5 seconds
  digitalWrite(relayPin, LOW);  // Turn relay OFF
  delay(5000);                   // Wait 5 seconds
}