diff --git a/Makefile b/Makefile
index 2b2f013..0011a68 100644
--- a/Makefile
+++ b/Makefile
@@ -53,6 +53,8 @@ CCARGS=-deprecation -classpath .
 ###############################################################
 
 FIRMWAREFILE = blinker2.ihex
+ESBFIRMWARE = firmware/esb/sensor-demo.firmware
+SKYFIRMWARE = firmware/sky/sensor-demo.firmware
 
 CPUTEST := tests/cputest.firmware
 
@@ -81,10 +83,10 @@ run:	compile
 	java se.sics.mspsim.util.IHexReader $(FIRMWAREFILE) $(MAPFILE)
 
 runesb:	compile
-	java se.sics.mspsim.platform.esb.ESBNode $(FIRMWAREFILE) $(MAPFILE)
+	java se.sics.mspsim.platform.esb.ESBNode $(ESBFIRMWARE) $(MAPFILE)
 
 runsky:	compile
-	java se.sics.mspsim.platform.sky.SkyNode $(FIRMWAREFILE) $(MAPFILE)
+	java se.sics.mspsim.platform.sky.SkyNode $(SKYFIRMWARE) $(MAPFILE)
 
 .PHONY: cputest test
 test:	cputest
diff --git a/firmware/esb/sensor-demo.firmware b/firmware/esb/sensor-demo.firmware
new file mode 100755
index 0000000..fb11444
Binary files /dev/null and b/firmware/esb/sensor-demo.firmware differ
diff --git a/se/sics/mspsim/core/IOPort.java b/se/sics/mspsim/core/IOPort.java
index df94ead..c852d7d 100644
--- a/se/sics/mspsim/core/IOPort.java
+++ b/se/sics/mspsim/core/IOPort.java
@@ -136,7 +136,9 @@ public class IOPort extends IOUnit {
       //   case IFG:
       if (interrupt > 0) {
 	// IFG - writing a zero => clear the flag!
-	System.out.println(getName() + " Clearing IFlag: " + data);
+	if (DEBUG) {
+	  System.out.println(getName() + " Clearing IFlag: " + data);
+	}
 	interruptFlag &= data;
 	memory[offset + IFG] = interruptFlag;
 	cpu.flagInterrupt(interrupt, this, interruptFlag > 0);
@@ -169,14 +171,19 @@ public class IOPort extends IOUnit {
 	  // LO/HI transition
 	  if (state == PIN_HI) {
 	    interruptFlag |= bit;
-	    System.out.println(getName() + " Flagging interrupt (HI): " + bit);
+	    if (DEBUG) {
+	      System.out.println(getName() +
+				 " Flagging interrupt (HI): " + bit);
+	    }
 	  }
 	} else {
 	  // HI/LO transition
 	  if (state == PIN_LOW) {
 	    interruptFlag |= bit;
-	    System.out.println(getName() + " Flagging interrupt (LOW): " +
-			       bit);
+	    if (DEBUG) {
+	      System.out.println(getName() +
+				 " Flagging interrupt (LOW): " + bit);
+	    }
 	  }
 	}
       }
diff --git a/se/sics/mspsim/platform/esb/ESBGui.java b/se/sics/mspsim/platform/esb/ESBGui.java
index 8d30ad7..0ae82a1 100644
--- a/se/sics/mspsim/platform/esb/ESBGui.java
+++ b/se/sics/mspsim/platform/esb/ESBGui.java
@@ -47,6 +47,7 @@ import java.awt.event.KeyEvent;
 import java.awt.event.KeyListener;
 import java.awt.event.MouseEvent;
 import java.awt.event.MouseMotionListener;
+import java.awt.event.MouseListener;
 import javax.swing.ImageIcon;
 import javax.swing.JComponent;
 import javax.swing.JFrame;
@@ -57,7 +58,8 @@ import se.sics.mspsim.util.SerialMon;
 import se.sics.mspsim.util.WindowUtils;
 
 public class ESBGui extends JComponent implements KeyListener,
-						  MouseMotionListener {
+						  MouseMotionListener,
+						  MouseListener {
 
   public static final int GREEN_X = 3;
   public static final int YELLOW_X = 10;
@@ -79,6 +81,7 @@ public class ESBGui extends JComponent implements KeyListener,
   private ImageIcon esbImage;
   private JFrame window;
   private ESBNode node;
+  private boolean buttonDown = false;
 
   public ESBGui(ESBNode node) {
     this.node = node;
@@ -103,6 +106,7 @@ public class ESBGui extends JComponent implements KeyListener,
 
     window.addKeyListener(this);
     window.addMouseMotionListener(this);
+    window.addMouseListener(this);
 
     // Add some windows for listening to serial output
     MSP430 cpu = node.getCPU();
@@ -130,8 +134,25 @@ public class ESBGui extends JComponent implements KeyListener,
     node.setVIB(x > 60 && x < 100 && y > 180 && y < 200);
   }
 
-  public void mouseDragged(MouseEvent e) {
+  public void mouseDragged(MouseEvent e) {}
+  public void mouseClicked(MouseEvent e) {}
+  public void mouseEntered(MouseEvent e) {}
+  public void mouseExited(MouseEvent e) {}
+
+  // For the button sensor on the ESB nodes.
+  public void mousePressed(MouseEvent e) {
+    int x = e.getX();
+    int y = e.getY();
+    if (x > 0 && x < 24 && y > 180 && y < 200) {
+      node.setButton(buttonDown = true);
+    }
   }
+  public void mouseReleased(MouseEvent e) {
+    if (buttonDown) {
+      node.setButton(buttonDown = false);
+    }
+  }
+
 
 
   public void paintComponent(Graphics g) {