diff --git a/labyrinthe/4-arduino_pyserial/4-labyrinthe-imu/4-labyrinthe-imu.ino b/labyrinthe/4-arduino_pyserial/4-labyrinthe-imu/4-labyrinthe-imu.ino
index 1e7b788..80170c6 100644
--- a/labyrinthe/4-arduino_pyserial/4-labyrinthe-imu/4-labyrinthe-imu.ino
+++ b/labyrinthe/4-arduino_pyserial/4-labyrinthe-imu/4-labyrinthe-imu.ino
@@ -42,8 +42,6 @@ Matrix_8x8 matrix;
  ******************************************************************************/
 
 String serial_msg = ""; // Message
-uint64_t serial_msg_int;
-String serial_msg_old = ""; // Message 
 bool serial_msg_complet = false;  // Flag de message complet
 
 /******************************************************************************
@@ -67,6 +65,8 @@ void setup() {
   matrix.setBlinkRate(BLINK_OFF);
   matrix.clear();
   matrix.display();
+  /* matrix.writeOnePicture(0xff90b2a2a6a4ae82); // Labyrinthe */
+  /* matrix.display(); */
 
   // Ok
   // Serial.println("Initialisation des composants I2C.");
@@ -113,19 +113,30 @@ void loop() {
     if (serial_msg_complet) {
 	/* matrix.writeString(serial_msg, 1000, ACTION_SCROLLING); */
 	/* matrix.display(); */
-	if (serial_msg.length() ==2) {
-	    if (serial_msg[0] == 'X') matrix.clear();
-	    if (serial_msg[0] == 'N') matrix.writeOnePicture(0x00000000000000ff);
-	    if (serial_msg[0] == 'E') matrix.writeOnePicture(0x8080808080808080);
-	    if (serial_msg[0] == 'S') matrix.writeOnePicture(0xff00000000000000);
-	    if (serial_msg[0] == 'O') matrix.writeOnePicture(0x0101010101010101);
-	}
-	if (serial_msg.length() ==3) {
-	    if ((serial_msg[0] == 'N') and (serial_msg[1] == 'E')) matrix.writeOnePicture(0x00000000808080f0);
-	    if ((serial_msg[0] == 'S') and (serial_msg[1] == 'E')) matrix.writeOnePicture(0xf080808000000000);
-	    if ((serial_msg[0] == 'S') and (serial_msg[1] == 'O')) matrix.writeOnePicture(0x0f01010100000000);
-	    if ((serial_msg[0] == 'N') and (serial_msg[1] == 'O')) matrix.writeOnePicture(0x000000000101010f);
-	}
+	/* matrix.clear(); */
+	/* matrix.display(); */
+	/* matrix.writeOnePicture(0xff90b2a2a6a4ae82); // Labyrinthe */
+	int xy= serial_msg.toInt();
+	int x= xy/10;
+	int y= xy-(x*10);
+	matrix.clear();
+	matrix.writePixel(x, y, true);
+
+	/* Orientation du plateau (N, NE, SE, S, SO, O, NO) */
+	/* if (serial_msg.length() ==2) { */
+	/*     if (serial_msg[0] == 'X') matrix.clear(); */
+	/*     if (serial_msg[0] == 'N') matrix.writeOnePicture(0x00000000000000ff); */
+	/*     if (serial_msg[0] == 'E') matrix.writeOnePicture(0x8080808080808080); */
+	/*     if (serial_msg[0] == 'S') matrix.writeOnePicture(0xff00000000000000); */
+	/*     if (serial_msg[0] == 'O') matrix.writeOnePicture(0x0101010101010101); */
+	/* } */
+	/* if (serial_msg.length() ==3) { */
+	/*     if ((serial_msg[0] == 'N') and (serial_msg[1] == 'E')) matrix.writeOnePicture(0x00000000808080f0); */
+	/*     if ((serial_msg[0] == 'S') and (serial_msg[1] == 'E')) matrix.writeOnePicture(0xf080808000000000); */
+	/*     if ((serial_msg[0] == 'S') and (serial_msg[1] == 'O')) matrix.writeOnePicture(0x0f01010100000000); */
+	/*     if ((serial_msg[0] == 'N') and (serial_msg[1] == 'O')) matrix.writeOnePicture(0x000000000101010f); */
+	/* } */
+	
 	matrix.display();
 	serial_msg = "";
 	serial_msg_complet = false;
@@ -134,7 +145,7 @@ void loop() {
 
     
 /******************************************************************************
- * Évenement provoqué UPBGE
+ * Évenement provoqué UPBGE (via la liaison série)
  ******************************************************************************/
 
 void serialEvent() {
diff --git a/labyrinthe/4-arduino_pyserial/4-labyrinthe.blend b/labyrinthe/4-arduino_pyserial/4-labyrinthe.blend
index f763cb9..0908b14 100644
Binary files a/labyrinthe/4-arduino_pyserial/4-labyrinthe.blend and b/labyrinthe/4-arduino_pyserial/4-labyrinthe.blend differ
diff --git a/labyrinthe/4-arduino_pyserial/4-labyrinthe.py b/labyrinthe/4-arduino_pyserial/4-labyrinthe.py
index 9adea41..97df49e 100644
--- a/labyrinthe/4-arduino_pyserial/4-labyrinthe.py
+++ b/labyrinthe/4-arduino_pyserial/4-labyrinthe.py
@@ -32,6 +32,9 @@ ACTIVATE = bge.logic.KX_INPUT_ACTIVE
 serial_baud=115200
 # serial_comm = serial.Serial('COM4',serial_baud, timeout=0.016) # Windows
 serial_comm = serial.Serial('/dev/ttyACM1',serial_baud, timeout=0.016) # GNU/Linux
+serial_msg_init = "99\n" # Vider la matrice de led
+serial_comm.write(serial_msg_init.encode())
+
 print (serial_comm)
 
 ###############################################################################
@@ -107,32 +110,40 @@ def  capteur(cont):
         y=-(float(y_txt)/57.3)  * resolution # 1/ 360 / (2 * pi)
         applyRotationTo(scene.objects['Plateau'], x,y, 0)
 
-        # Ecriture sur la liaison série : programme Arduino : 3-labyrinthe-imu.ino
+        # Ecriture de l'orientation du plateau sur la liaison série : programme Arduino : 3-labyrinthe-imu.ino
         obj['Rx']=obj.worldOrientation.to_euler().x*57.3
         obj['Ry']=obj.worldOrientation.to_euler().y*57.3
         obj['Rz']=obj.worldOrientation.to_euler().z*57.3
+        # if obj['Rx']<-2 and obj['Ry'] >-2 and obj['Ry'] <2:
+        #     serial_msg_out = "N\n"
+        # if obj['Rx']>2 and obj['Ry'] >-2 and obj['Ry'] <2:
+        #     serial_msg_out = "S\n"
+        # if obj['Rx']>-2 and obj['Rx']<2 and obj['Ry'] <-2 :
+        #     serial_msg_out = "O\n"
+        # if obj['Rx']>-2 and obj['Rx']<2 and obj['Ry'] > 2 :
+        #     serial_msg_out = "E\n"
+        # if obj['Rx']<-2 and obj['Ry'] <-2 :
+        #     serial_msg_out = "NO\n"
+        # if obj['Rx']<-2 and obj['Ry'] > 2 :
+        #     serial_msg_out = "NE\n"
+        # if obj['Rx']>2 and obj['Ry'] <-2 :
+        #     serial_msg_out = "SO\n"
+        # if obj['Rx']>2 and obj['Ry'] > 2 :
+        #     serial_msg_out = "SE\n"
+        # if obj['Rx']>-2 and obj['Rx']<2 and obj['Ry'] >-2 and obj['Ry'] <2:
+        #     serial_msg_out = "X\n"
 
-        if obj['Rx']<-2 and obj['Ry'] >-2 and obj['Ry'] <2:
-            serial_msg_out = "N\n"
-        if obj['Rx']>2 and obj['Ry'] >-2 and obj['Ry'] <2:
-            serial_msg_out = "S\n"
-        if obj['Rx']>-2 and obj['Rx']<2 and obj['Ry'] <-2 :
-            serial_msg_out = "O\n"
-        if obj['Rx']>-2 and obj['Rx']<2 and obj['Ry'] > 2 :
-            serial_msg_out = "E\n"
-
-        if obj['Rx']<-2 and obj['Ry'] <-2 :
-            serial_msg_out = "NO\n"
-        if obj['Rx']<-2 and obj['Ry'] > 2 :
-            serial_msg_out = "NE\n"
-        if obj['Rx']>2 and obj['Ry'] <-2 :
-            serial_msg_out = "SO\n"
-        if obj['Rx']>2 and obj['Ry'] > 2 :
-            serial_msg_out = "SE\n"
-            
-        if obj['Rx']>-2 and obj['Rx']<2 and obj['Ry'] >-2 and obj['Ry'] <2:
-            serial_msg_out = "X\n"
-
+        # Ecriture de la position de la bille sur la liaison série : programme Arduino : 3-labyrinthe-imu.ino
+        obj_bille = scene.objects['Bille']
+        obj_bille['x'] = obj_bille.worldPosition.x # de -3.5 à 3.5
+        obj_bille['y'] = obj_bille.worldPosition.y # de 3.5 à -3.5
+        obj_bille['Lx']=-1*round(obj_bille.worldPosition.x-3.5)  # de 7 à 0
+        if obj_bille['Lx']<0: obj_bille['Lx']=0 
+        if obj_bille['Lx']>7: obj_bille['Lx']=7
+        obj_bille['Ly']=-1*round(obj_bille.worldPosition.y-3.5) # de 0 à 7
+        if obj_bille['Ly']<0: obj_bille['Ly']=0
+        if obj_bille['Ly']>7:  obj_bille['Ly']=7
+        serial_msg_out = str(obj_bille['Lx'])+str(obj_bille['Ly'])+"\n"
         serial_comm.write(serial_msg_out.encode())
     
 ###############################################################################