// the setup function runs once when you press reset or power the board void setup() { pinMode(25, OUTPUT); //relay1 pinMode(32, OUTPUT); //relay2 pinMode(26, OUTPUT); //relay3 pinMode(33, OUTPUT); //relay4 } // the loop function runs over and over again forever void loop() { digitalWrite(25, HIGH); digitalWrite(32, HIGH); digitalWrite(26, HIGH); digitalWrite(33, HIGH); delay(1000); // wait for a second digitalWrite(25, LOW); digitalWrite(32, LOW); digitalWrite(26, LOW); digitalWrite(33, LOW); delay(1000); // wait for a second }