 // DS3231:  SDA pin   -> Arduino Digital 20 (SDA) or the dedicated SDA1 (Digital 70) pin
 //          SCL pin   -> Arduino Digital 21 (SCL) or the dedicated SCL1 (Digital 71) pin
 
+/*
+ * Keyboard Password Printing
+ *
+ * When button is pressed, will type "this is your password".
+ *
+ * The circuit:
+ * - button attached from pin 42 to +3.3V
+ * - 10-kilohm resistor attached from pin 42 to ground
+ *
+ *
+ * Based off of the example from:
+ * http://www.arduino.cc/en/Tutorial/KeyboardMessage
+ */
+
 #include <DS3231.h>
 #include <SPI.h>
 #include <SD.h>
 
+#define BUTTON_PIN 42
 #define SD_PIN 4
 #define KEY_FILE "key.txt"
 
 DS3231 rtc(SDA, SCL);
 String key = "";
+int previousButtonState = HIGH;
 
 // Gets a UNIX timestamp from the RTC
 long getTimestamp() {

  int month = readInt("Month");
  int day = readInt("Day");
  rtc.setDate(day, month, year);
  
  int hour = readInt("Hour");
  int minute = readInt("Minute");
  int second = readInt("Second");

void setup() {
  // Set up the serial terminal
  Serial.begin(115200);

  // Set up the button
  pinMode(BUTTON_PIN, INPUT);

  // Set up the real time clock
  rtc.begin();

  // Set up the SD card
  pinMode(10, OUTPUT);
  if (!SD.begin(SD_PIN)) {
