void setup() {
pinMode(led1, OUTPUT); // initialize digital pin led1 as an
output.
int counter=0;
}
void loop()
{
  digitalWrite(led1, HIGH);  // turn the
led1 on (HIGH is the voltage level)
  delay(4000);              //
led1 stay on for 4seconds=4000 milliseconds
  digitalWrite(led1, LOW);    //
turn the led1 off by making the voltage LOW
  delay(2000);              //
led1 stay off for 2 seconds=2000 milliseconds
counter++; // this statement makes the program indefinetely
repeat itself
}
Now program for 20 seconds ON and 10 seconds OFF is shown
below
void setup()
{ Â Â
pinMode(led1, OUTPUT);
int counter=0;
}
void loop()
{
digitalWrite(led1, HIGH);
delay(20000); // 20 seconds = 20000 milliseconds
digitalWrite(led1, LOW);
delay(10000); // 10seconds =10000 milliseconds
counter++;
}
IF YOU HAVE QUERY PLEASE POST A COMMENT , LIKE MY ANSEWER THANKS
IN ADVANCE
