Greenhouse_timer.ino

// pumpOnInterval turn pump on for x
const unsigned long pumpOnInterval = (30 * 1000);
// pumpOffInterval turn pump off for x
const unsigned long pumpOffInterval = (60*60*1000);
// Which pins are connected to which LED/Pump
const byte pumpPin = 0;
const byte ledPin = 1;

// Variable holding the timer value so far. One for each "Timer"
unsigned long pumpTimer;

void setup() {
  // set pumpPin to output
  pinMode(pumpPin, OUTPUT);
  pinMode(ledPin, OUTPUT);
  // set off
  digitalWrite (pumpPin, LOW);
  digitalWrite (ledPin, LOW);
  // Set timer
  pumpTimer = millis (); 
}

void pumpOn ()
  {
    // remember when we toggled it
    pumpTimer = millis (); 
    while (millis() - pumpTimer < pumpOnInterval) {
      digitalWrite (pumpPin, HIGH);
      digitalWrite(ledPin, HIGH);
    }
  }  // end of pumpOn

void pumpOff ()
  {
    digitalWrite (pumpPin, LOW);
    toggleLED ();    
  }  // end of pumpOff
  
// This function switches over the Led when is called
void toggleLED (void){
  if(digitalRead(ledPin)==HIGH){ digitalWrite(ledPin, LOW);   }
  else{                       digitalWrite(ledPin, HIGH);  }
  delay(100);
}

void loop() {
  // Turn pump on if millis - pumpTimer is greater than or equal to 1 hour
  if ( (millis () - pumpTimer) >= pumpOffInterval) {
    pumpOn ();
  }
  // Turn pump off
else {
    pumpOff ();
  }
}