diff --git a/hoverserial.ino b/hoverserial.ino
index ca809c6..5061d72 100644
--- a/hoverserial.ino
+++ b/hoverserial.ino
@@ -278,8 +278,9 @@ void Nunchuk_control()
 
 // ########################## LOOP ##########################
 
-unsigned long iTimeSend = 0;
-int idx_led = 0;
+unsigned long iTimeSendR = 0, iTimeSendL = 0;
+int idx_ledR = 0, idx_ledL = 0;
+int speedR, speedL;
 
 void loop()
 {
@@ -289,35 +290,77 @@ void loop()
   digitalWrite(LED_BUILTIN, (timeNow % 2000) < 1000);
   Receive();
   Nunchuk_control();
+
+  // ********************* simulation *********************************
+  // in final project need to use Feedback.speedR_meas and Feedback.speedL_meas
+  //
+  speedR = cmd2 + cmd1;
+  speedL = cmd2 - cmd1;
+  //
+  // ********************* simulation *********************************
   strip.clear();
-  strip.setPixelColor(idx_led, strip.Color(128, 0, 0));
-  strip.setPixelColor((NB_STRIP * LED_STRIP) - 1 - idx_led, strip.Color(128, 0, 0)); // second LEDs strip
+  strip.setPixelColor(idx_ledR, strip.Color(128, 0, 0));
+  strip.setPixelColor((NB_STRIP * LED_STRIP) - 1 - idx_ledL, strip.Color(128, 0, 0)); // second LEDs strip
   strip.show();
-  if (iTimeSend > timeNow)
-    return;
-  if (cmd2 == 0)
-    return;
-  iTimeSend = timeNow + ((200 - abs(cmd2)) * 2); // TIME_SEND
-  if (cmd2 > 0)
+
+  //*********** 1st led strip ******************
+  if (timeNow > iTimeSendR)
   {
-    if (idx_led < LED_STRIP - 1)
-    {
-      idx_led++;
-    }
-    else
+    if (speedR != 0)
     {
-      idx_led = 0;
+      iTimeSendR = timeNow + ((200 - abs(speedR)) * 2); // TIME_SEND
+      if (speedR > 0)
+      {
+        if (idx_ledR < LED_STRIP - 1)
+        {
+          idx_ledR++;
+        }
+        else
+        {
+          idx_ledR = 0;
+        }
+      }
+      else
+      {
+        if (idx_ledR > 0)
+        {
+          idx_ledR--;
+        }
+        else
+        {
+          idx_ledR = LED_STRIP - 1;
+        }
+      }
     }
   }
-  else
+  //*********** 2nd led strip ******************
+  if (timeNow > iTimeSendL)
   {
-    if (idx_led > 0)
-    {
-      idx_led--;
-    }
-    else
+    if (speedL != 0)
     {
-      idx_led = LED_STRIP - 1;
+      iTimeSendL = timeNow + ((200 - abs(speedL)) * 2); // TIME_SEND
+      if (speedL > 0)
+      {
+        if (idx_ledL < LED_STRIP - 1)
+        {
+          idx_ledL++;
+        }
+        else
+        {
+          idx_ledL = 0;
+        }
+      }
+      else
+      {
+        if (idx_ledL > 0)
+        {
+          idx_ledL--;
+        }
+        else
+        {
+          idx_ledL = LED_STRIP - 1;
+        }
+      }
     }
   }
 }