int rel = 13;
int s1;

void setup() {
pinMode(rel, OUTPUT);
pinMode(2, INPUT);
}
void loop() {
s1 = digitalRead(2); 
/*
                .-"""-.    .-"""-.
               /       `..'       \
        _     |                    |
     .-' /    |        L A         |    /////
    <   <======\   Mama de rodri  /====<<<<<
     '-._\      \                /      \\\\\
                 `\            /'
                   `\        /'
                     `\    /'
                       `\/'
*/
if(s1 == 1){
digitalWrite(rel, HIGH);
delay(50);
}
else{
  digitalWrite(rel, LOW);
}
}