#include <Arduino.h>
#include <stdio.h>
#include <serial_interface.h>

/* There are two buttons on the device */
/* left button - below and to the left of RESET */
/* right button - below and to the right of RESET */
/* When you press the left button the LED will turn on */

#define LED_PIN 13                   /* LED connected to digital pin 13 */
#define LEFT_BUTTON_PIN 4            /* Left button connected to pin 4  */
#define RIGHT_BUTTON_PIN 19          /* Right button connect to pin 19  */

int push_button = LEFT_BUTTON_PIN;  /* Try push_button = RIGHT_BUTTON_PIN */

void setup() {
  pinMode(LED_PIN, OUTPUT);          /* Sets the digital pin 13 as output */
  pinMode(push_button, INPUT);        /* Using left button; try right button */
}

void loop() {
  int value_read = digitalRead(push_button);   /* Read whether button is pressed */
  digitalWrite(LED_PIN, value_read);      /* Sets the LED to the button's value */
}