   pulser.pulse();
   display.display_time( time_remaining / 1000 );
 
+
   running_state_loop_buttons(button);
 }
 
 void beeping_state_loop (int button) {
+
+  if (millis() % PULSER_FLASH_PERIOD > PULSER_FLASH_PERIOD / 2 ) {
+    tone(PIN_SPEAKER, 400);
+  } else {
+    noTone(PIN_SPEAKER);
+  }
 
   pulser.flash();
   display.display_time( 0 );

  Serial.println("Starting up!");

  buttons.setup();

  countdown_ends = 0;
  countdown_duration = 900000; // 15 mins in ms



void change_to_state(int new_state) {

  noTone(PIN_SPEAKER);

  if (new_state == STATE_WAITING) {
    current_state = STATE_WAITING;
  } else if (new_state == STATE_RUNNING) {
