 */
 LiquidCrystal lcd(12, 11, 5, 4, 3, 2);
 const char armingPin = 6;
-char armingButtonState = 0;
+char armingButtonState = LOW;
+
+// armed indicator led pin
+const char armedPin = 8;
+
+// user trigger button pin and state
+const char triggerPin = 7;
+char triggerState = LOW;
 
 // the controller must be armed by an I2C message before the user button will be
 // activated. Once armed the system cannot be armed again until after a
 // countdown and I2C send
 boolean systemArmed = false;
+
+// countdown timer = 5 seconds
+const unsigned long interval = 5000;
 
 void setup() {
   // start I2C slave

  if (armingButtonState == HIGH) {
    receiveData(1);
  }
}

void receiveData(int numBytes) {
  if (!systemArmed) {
    systemArmed = true;
    
    /*
    * temporary
    */

void sendData() {
  
}

// nonblocking countdown timer
void countdown() {
  long curr = millis();
  long delta = millis() - curr;
  while (interval - delta >= 0) {
    /*
    * temporary
    */
    lcd.setCursor(0,0);
    lcd.print((interval - delta) / 1000);
  }
}

