/* Blink Turns on an LED on for one second, then off for one second, repeatedly. Most Arduinos have an on-board LED you can control. On the Uno and Leonardo, it is attached to digital pin 13. If you're unsure what pin the on-board LED is connected to on your Arduino model, check the documentation at http://www.arduino.cc This example code is in the public domain. modified 8 May 2014 by Scott Fitzgerald */ int relay = 13; // the setup function runs once when you press reset or power the board void setup() { // initialize digital pin 13 as an output. pinMode(relay, OUTPUT); } // the loop function runs over and over again forever void loop() { digitalWrite(relay, HIGH); // turn the LED on (HIGH is the voltage level) delay(1000); // wait for a second digitalWrite(relay, LOW); // turn the LED off by making the voltage LOW delay(1000); // wait for a second }