#include <SoftwareSerial.h>

SoftwareSerial mySerial(0, 1);
void setup() {
  // put your setup code here, to run once:
mySerial.begin(9600);
pinMode (3,INPUT_PULLUP);
}

void loop() {

  if (digitalRead(3)==LOW){ 
    mySerial.println("Hola");
    delay(100);
  }
}