const int relayPin = 8; // Define the pin to which the relay module is connected
const unsigned long onDuration = 5000; // Duration in milliseconds (5 seconds in this example)

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

void loop() {
  // Your condition here
  bool conditionIsTrue = true; // Replace this with your actual condition

  if (conditionIsTrue) {
    digitalWrite(relayPin, HIGH); // Turn the relay ON
    delay(onDuration); // Wait for the specified duration
    digitalWrite(relayPin, LOW); // Turn the relay OFF
  }

  // Your other loop code here
}