diff --git a/tools/cooja/apps/mspsim/src/se/sics/cooja/mspmote/SkyMoteType.java b/tools/cooja/apps/mspsim/src/se/sics/cooja/mspmote/SkyMoteType.java
index 186d069a7..402ad1ec6 100644
--- a/tools/cooja/apps/mspsim/src/se/sics/cooja/mspmote/SkyMoteType.java
+++ b/tools/cooja/apps/mspsim/src/se/sics/cooja/mspmote/SkyMoteType.java
@@ -26,7 +26,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- * $Id: SkyMoteType.java,v 1.13 2009/12/02 17:12:32 fros4943 Exp $
+ * $Id: SkyMoteType.java,v 1.14 2010/01/21 17:43:59 fros4943 Exp $
  */
 
 package se.sics.cooja.mspmote;
@@ -58,6 +58,7 @@ import se.sics.cooja.interfaces.Mote2MoteRelations;
 import se.sics.cooja.interfaces.Position;
 import se.sics.cooja.interfaces.RimeAddress;
 import se.sics.cooja.mspmote.interfaces.MspClock;
+import se.sics.cooja.mspmote.interfaces.MspDebugOutput;
 import se.sics.cooja.mspmote.interfaces.MspMoteID;
 import se.sics.cooja.mspmote.interfaces.SkyButton;
 import se.sics.cooja.mspmote.interfaces.SkyByteRadio;
@@ -214,7 +215,8 @@ public class SkyMoteType extends MspMoteType {
         SkyCoffeeFilesystem.class,
         SkyByteRadio.class,
         MspSerial.class,
-        SkyLED.class
+        SkyLED.class,
+        MspDebugOutput.class /* EXPERIMENTAL */
     };
   }
 
diff --git a/tools/cooja/apps/mspsim/src/se/sics/cooja/mspmote/interfaces/MspDebugOutput.java b/tools/cooja/apps/mspsim/src/se/sics/cooja/mspmote/interfaces/MspDebugOutput.java
new file mode 100644
index 000000000..48958d827
--- /dev/null
+++ b/tools/cooja/apps/mspsim/src/se/sics/cooja/mspmote/interfaces/MspDebugOutput.java
@@ -0,0 +1,138 @@
+/*
+ * Copyright (c) 2007, Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the Institute nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $Id: MspDebugOutput.java,v 1.1 2010/01/21 17:43:59 fros4943 Exp $
+ */
+
+package se.sics.cooja.mspmote.interfaces;
+
+import java.util.Collection;
+
+import javax.swing.JPanel;
+
+import org.apache.log4j.Logger;
+import org.jdom.Element;
+
+import se.sics.cooja.ClassDescription;
+import se.sics.cooja.Mote;
+import se.sics.cooja.interfaces.Log;
+import se.sics.cooja.mspmote.MspMote;
+import se.sics.cooja.mspmote.MspMoteMemory;
+import se.sics.mspsim.core.CPUMonitor;
+
+/**
+ * Observes writes to a special (hardcoded) Contiki variable: cooja_debug_ptr.
+ * When the pointer is changed, the string that the pointer points to 
+ * is outputted as log output from this mote interface.
+ * 
+ * Contiki code example:
+ *  cooja_debug_ptr = "Almost non-intrusive debug output";
+ * or simply:
+ *  COOJA_DEBUG("Almost non-intrusive debug output");
+ *  
+ * @author Fredrik Osterlind
+ */
+@ClassDescription("Debugging output")
+public class MspDebugOutput extends Log {
+  private static Logger logger = Logger.getLogger(MspDebugOutput.class);
+
+  private final static String CONTIKI_POINTER = "cooja_debug_ptr";
+  
+  private MspMote mote;
+  private MspMoteMemory mem;
+  
+  private String lastLog = null;
+  
+  public MspDebugOutput(Mote mote) {
+    this.mote = (MspMote) mote;
+    this.mem = (MspMoteMemory) this.mote.getMemory();
+
+    this.mote.getCPU().setBreakPoint(mem.getVariableAddress(CONTIKI_POINTER),
+        new CPUMonitor() {
+      public void cpuAction(int type, int adr, int data) {
+        if (type != MEMORY_WRITE) {
+          return;
+        }
+
+        String msg = extractString(mem, data);
+        if (msg != null && msg.length() > 0) {
+          lastLog = "DEBUG: " + msg;
+          setChanged();
+          notifyObservers(MspDebugOutput.this.mote);
+        }
+      }
+    });
+    
+  }
+
+  private String extractString(MspMoteMemory mem, int address) {
+    StringBuilder sb = new StringBuilder();
+    while (true) {
+      byte[] data = mem.getMemorySegment(address, 8);
+      address += 8;
+      for (byte b: data) {
+        if (b == 0) {
+          return sb.toString();
+        }
+        sb.append((char)b);
+        if (sb.length() > 128) {
+          /* Maximum size */
+          return sb.toString() + "...";
+        }
+      }
+    }
+  }
+  
+  public Mote getMote() {
+    return mote;
+  }
+
+  public String getLastLogMessage() {
+    return lastLog;
+  }
+
+  public Collection<Element> getConfigXML() {
+    return null;
+  }
+
+  public void setConfigXML(Collection<Element> configXML, boolean visAvailable) {
+    /* Observed Contiki pointer is hardcoded */
+  }
+
+  public JPanel getInterfaceVisualizer() {
+    return null;
+  }
+
+  public void releaseInterfaceVisualizer(JPanel panel) {
+  }
+
+  public void removed() {
+    super.removed();
+    /* TODO Remove watchpoint */
+  }
+}