const int relayPin = 4;
void setup() {
  Serial.begin(115200);
  pinMode( relayPin, OUTPUT);  
}
void loop() {
  digitalWrite(relayPin, HIGH); 
  Serial.println("Relay NO is ON!");  
  Serial.println("LED is ON!");
  delay(3000); 
  digitalWrite(relayPin, LOW); 
  Serial.println("Relay NO is OFF!");  
  Serial.println("LED is OFF!");
  delay(3000); 
}