#define relay1 7

void setup() {
  // put your setup code here, to run once:
Serial.begin(9600);
pinMode(relay1, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly: 
  digitalWrite(relay1, HIGH);
  Serial.println("ON");
  delay(300);
  digitalWrite(relay1, LOW);
  Serial.println("OFF");
  delay(300);
}