diff --git a/tools/cooja/java/se/sics/cooja/plugins/TimeLine.java b/tools/cooja/java/se/sics/cooja/plugins/TimeLine.java
index 2f3f8b343..e58e754a8 100644
--- a/tools/cooja/java/se/sics/cooja/plugins/TimeLine.java
+++ b/tools/cooja/java/se/sics/cooja/plugins/TimeLine.java
@@ -26,7 +26,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- * $Id: TimeLine.java,v 1.10 2009/06/25 16:44:08 fros4943 Exp $
+ * $Id: TimeLine.java,v 1.11 2009/07/02 12:05:24 fros4943 Exp $
  */
 
 package se.sics.cooja.plugins;
@@ -81,6 +81,7 @@ import se.sics.cooja.Simulation;
 import se.sics.cooja.VisPlugin;
 import se.sics.cooja.Watchpoint;
 import se.sics.cooja.WatchpointMote;
+import se.sics.cooja.SimEventCentral.MoteCountListener;
 import se.sics.cooja.interfaces.LED;
 import se.sics.cooja.interfaces.Radio;
 import se.sics.cooja.interfaces.Radio.RadioEvent;
@@ -114,8 +115,7 @@ public class TimeLine extends VisPlugin {
   private int paintedMoteHeight = EVENT_PIXEL_HEIGHT;
 
   private Simulation simulation;
-  private Observer simulationObserver;
-  private int simulationObserverLast = -1;
+  private MoteCountListener newMotesListener;
 
   private JScrollPane timelineScrollPane;
   private MoteRuler timelineMoteRuler;
@@ -242,39 +242,17 @@ public class TimeLine extends VisPlugin {
     numberMotesWasUpdated();
 
     /* Automatically add/delete motes */
-    simulation.addObserver(simulationObserver = new Observer() {
-      public void update(Observable obs, Object obj) {
-        if (simulation.getMotesCount() == simulationObserverLast) {
-          /* TODO Detect added/removed motes by event types, not mote counts */
-          return;
-        }
-        simulationObserverLast = simulation.getMotesCount();
-
-        /* Unregister removed motes */
-        Mote[] simMotes = simulation.getMotes();
-        MoteEvents[] allMoteEventsArr = allMoteEvents.toArray(new MoteEvents[0]);
-        for (MoteEvents moteEvents: allMoteEventsArr) {
-          /* Check that mote still exists in simulation */
-          boolean exists = false;
-          for (Mote existing: simMotes) {
-            if (existing == moteEvents.mote) {
-              exists = true;
-              break;
-            }
-          }
-
-          if (!exists) {
-            removeMote(moteEvents.mote);
-          }
-        }
-
-        /* Add all simulation motes */
-        for (Mote m: simulation.getMotes()) {
-          addMote(m);
-        }
+    simulation.getEventCentral().addMoteCountListener(newMotesListener = new MoteCountListener() {
+      public void moteWasAdded(Mote mote) {
+        addMote(mote);
+      }
+      public void moteWasRemoved(Mote mote) {
+        removeMote(mote);
       }
     });
-    simulationObserver.update(null, null);
+    for (Mote m: simulation.getMotes()) {
+      addMote(m);
+    }
     
     /* Update timeline for the duration of the plugin */
     repaintTimelineTimer.start();
@@ -665,7 +643,7 @@ public class TimeLine extends VisPlugin {
     /* Remove repaint timer */
     repaintTimelineTimer.stop();
 
-    simulation.deleteObserver(simulationObserver);
+    simulation.getEventCentral().removeMoteCountListener(newMotesListener);
     
     /* Remove active mote interface observers */
     for (MoteObservation o: activeMoteObservers) {
@@ -740,7 +718,6 @@ public class TimeLine extends VisPlugin {
     for (MoteEvents moteEvents: allMoteEventsArr) {
       removeMote(moteEvents.mote);
     }
-    simulationObserverLast = simulation.getMotesCount();
     
     for (Element element : configXML) {
       String name = element.getName();
diff --git a/tools/cooja/java/se/sics/cooja/plugins/Visualizer.java b/tools/cooja/java/se/sics/cooja/plugins/Visualizer.java
index ef2b04c7b..106591108 100644
--- a/tools/cooja/java/se/sics/cooja/plugins/Visualizer.java
+++ b/tools/cooja/java/se/sics/cooja/plugins/Visualizer.java
@@ -26,7 +26,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- * $Id: Visualizer.java,v 1.7 2009/06/10 15:57:08 fros4943 Exp $
+ * $Id: Visualizer.java,v 1.8 2009/07/02 12:05:54 fros4943 Exp $
  */
 
 package se.sics.cooja.plugins;
@@ -55,6 +55,7 @@ import org.jdom.Element;
 
 import se.sics.cooja.*;
 import se.sics.cooja.GUI.MoteRelation;
+import se.sics.cooja.SimEventCentral.MoteCountListener;
 import se.sics.cooja.interfaces.*;
 import se.sics.cooja.plugins.skins.AddressVisualizerSkin;
 import se.sics.cooja.plugins.skins.IDVisualizerSkin;
@@ -117,7 +118,7 @@ public class Visualizer extends VisPlugin {
   private ArrayList<VisualizerSkin> currentSkins = new ArrayList<VisualizerSkin>();
 
   /* Generic visualization */
-  private Observer simObserver = null;
+  private MoteCountListener newMotesListener;
   private Observer posObserver = null;
   private Observer moteHighligtObserver = null;
   private Vector<Mote> highlightedMotes = new Vector<Mote>();
@@ -239,22 +240,32 @@ public class Visualizer extends VisPlugin {
         repaint();
       }
     };
-    simulation.addObserver(simObserver = new Observer() {
-      public void update(Observable obs, Object obj) {
-
-        /* Observe mote positions */
-        for (Mote mote: Visualizer.this.simulation.getMotes()) {
-          Position posIntf = mote.getInterfaces().getPosition();
-          if (posIntf != null) {
-            posIntf.addObserver(posObserver);
-          }
+    simulation.getEventCentral().addMoteCountListener(newMotesListener = new MoteCountListener() {
+      public void moteWasAdded(Mote mote) {
+        Position pos = mote.getInterfaces().getPosition();
+        if (pos != null) {
+          pos.addObserver(posObserver);
+        }
+        calculateTransformations();
+        repaint();
+      }
+      public void moteWasRemoved(Mote mote) {
+        Position pos = mote.getInterfaces().getPosition();
+        if (pos != null) {
+          pos.deleteObserver(posObserver);
         }
-
         calculateTransformations();
         repaint();
       }
     });
-    simObserver.update(null, null);
+    for (Mote mote: simulation.getMotes()) {
+      Position pos = mote.getInterfaces().getPosition();
+      if (pos != null) {
+        pos.addObserver(posObserver);
+      }
+    }
+    calculateTransformations();
+    repaint();
 
     /* Observe mote highlights */
     gui.addMoteHighlightObserver(moteHighligtObserver = new Observer() {
@@ -908,14 +919,11 @@ public class Visualizer extends VisPlugin {
       gui.deleteMoteRelationsObserver(moteRelationsObserver);
     }
 
-    if (simObserver != null) {
-      simulation.deleteObserver(simObserver);
-
-      for (int i = 0; i < simulation.getMotesCount(); i++) {
-        Position posIntf = simulation.getMote(i).getInterfaces().getPosition();
-        if (posIntf != null) {
-          posIntf.deleteObserver(posObserver);
-        }
+    simulation.getEventCentral().removeMoteCountListener(newMotesListener);
+    for (Mote mote: simulation.getMotes()) {
+      Position pos = mote.getInterfaces().getPosition();
+      if (pos != null) {
+        pos.deleteObserver(posObserver);
       }
     }
   }