Temperature control using relay.

Projects General Guidance
29

I want to start the my relays in off state ,Thats why i set all out puts to HIGH.And i also set exhaust pin to LOW when temperature starts rising above 30,Then only the counting to start.

 if (exhaustState == LOW) {
    if ((roomtemp >= 30) && (digitalRead(coolerpin) == HIGH )) {
      digitalWrite(exhaustpin, LOW ); // if temperature increses above 30 the exhaust starts to work
      startingCount = millis();
    }
  }
  if (digitalRead(exhaustpin) == LOW) {
    exhaustState = HIGH ;
    if ((millis() - startingCount) >= 600000) {
      digitalWrite(coolerpin, LOW );
      digitalWrite(exhaustpin, HIGH );  // after the starting of exhaust fan it wait for 10 minutes ,then it turn
      // on the cooler and turns off the exhaust fan
    }
  }