diff --git a/sksurgerybard/interaction/interaction.py b/sksurgerybard/interaction/interaction.py
index 52576e7..53319c3 100644
--- a/sksurgerybard/interaction/interaction.py
+++ b/sksurgerybard/interaction/interaction.py
@@ -33,8 +33,10 @@ def __call__(self, event, _event_type_not_used):
             self._translate_model(key)
         if key in '8i9o0p':
             self._rotate_model(key)
-        if key == 'f':
-            self._bard_widget.tracking = not self._bard_widget.tracking
+        if key == 'Up':
+            self._bard_widget.tracker.stop_tracking()
+        if key == 'Down':
+            self._bard_widget.tracker.start_tracking()
 
 
     def _translate_model(self, key):
diff --git a/sksurgerybard/widgets/bard_overlay_app.py b/sksurgerybard/widgets/bard_overlay_app.py
index 65be060..bdcccf8 100644
--- a/sksurgerybard/widgets/bard_overlay_app.py
+++ b/sksurgerybard/widgets/bard_overlay_app.py
@@ -43,8 +43,6 @@ def __init__(self, configuration = None, calib_dir = None):
 
         self.tracker, self.transform_manager = setup_tracker(configuration)
         self.tracker.start_tracking()
-        self.tracking = True # A boolean that we can manipulate to start/
-                             # stop tracking
 
         self.transform_manager.add("tracker2camera",
                         np.eye(4, dtype = np.float64))
@@ -168,8 +166,7 @@ def update(self):
 
         undistorted = cv2.undistort(image, self.mtx33d, self.dist15d)
 
-        if self.tracking:
-            self._update_tracking(image)
+        self._update_tracking(image)
 
         self._update_overlay_window()
 
@@ -191,11 +188,17 @@ def _update_tracking(self, image):
         tracking = []
         if (isinstance(self.tracker, ArUcoTracker) and not
                         self.tracker.has_capture()):
-            port_handles, _timestamps, _framenumbers, tracking, quality = \
-                        self.tracker.get_frame(image)
+            try:
+                port_handles, _timestamps, _framenumbers, tracking, \
+                    quality = self.tracker.get_frame(image)
+            except ValueError:
+                return
         else:
-            port_handles, _timestamps, _framenumbers, tracking, quality = \
-                        self.tracker.get_frame()
+            try:
+                port_handles, _timestamps, _framenumbers, tracking, \
+                        quality = self.tracker.get_frame()
+            except ValueError:
+                return
 
         for index, port_handle in enumerate(port_handles):
             if (not np.isnan(quality[index])) and quality[index] > 0.2: