5v Power Source - Center Tap Transformer, Diode Bridge Rectifier, 7805, Relay and Lamp Sample

By rhaseven7h 
void setup()
{
  Serial.println("Starting ...");
  pinMode(13, OUTPUT);
}

void loop()
{
  Serial.println("Cycling on ...");
  digitalWrite(13, HIGH);
  delay(2000);
  Serial.println("Cycling off ...");
  digitalWrite(13, LOW);
  delay(2000);
}