I test my code using BoardMicro, an AVR simulator app

https://play.google.com/store/apps/details?id=org.starlo.boardmicro

#define RelayPin 12
#define MilliSecondsPerDay 86400000
#define MilliSecondsPerMinute 60000

void setup() {                
  pinMode(RelayPin, OUTPUT);     
}

void loop() {
  digitalWrite(RelayPin, LOW);
  delay(5*MilliSecondsPerMinute);
  digitalWrite(RelayPin, HIGH);
  delay(MilliSecondsPerDay*3);
}

For internal details

https://twitter.com/xlivewire/status/504109476350144512