#define  RELAY_PIN 25

void setup() {
  pinMode(RELAY_PIN, OUTPUT);
  Serial.begin(9600);
  digitalWrite(RELAY_PIN, HIGH);
  // put your setup code here, to run once:
}

void loop() {
  digitalWrite(RELAY_PIN, LOW);
  Serial.println("Relay OFF");
  delay(2000);
  digitalWrite(RELAY_PIN, HIGH);
  Serial.println("Relay ON");
  delay(2000);

}