How to Control an AC Bulb with a Relay and Digispark USB Board

/*
 Digispark Relay
 Turn a bulb, AC or DC load ON/OFF 

 Written by Ahmad Shamshiri at 18:21 on Saturday, May 11, 2019 for Robojax
 in Ajax, Ontario, Canada
 www.Robojax.com
  Watch video instructions for this code: https://youtu.be/THgyVQE5yrA
 
*/


int relay = 0;// define a pin for relay output

// The setup function runs once when you press reset or power the board
void setup() {

  pinMode(relay, OUTPUT);// define "relay" as output
}

// The loop function runs over and over again forever
void loop() {

     digitalWrite(relay, LOW);// turn relay pin LOW (ON)
     delay(300);// give it a little time (100ms)

     digitalWrite(relay, HIGH);// turn relay pin HIGH (OFF)
     delay(300);// give it a little time (100ms)  
                 
}