@Override
 protected void onResume() {
   super.onResume();
   pitchPoster = new MicrophonePitchSource();
   pitchPoster.setHandler(new UIUpdateHandler());
   pitchPoster.startSampling();
 }
 @Override
 protected void onPause() {
   super.onPause();
   pitchPoster.stopSampling();
   pitchPoster = null;
 }