 
 LinFrame frame = LinFrame();
 
-unsigned long lastHeartbeat, lastBackDown, lastEnterDown, lastMouseDown;
+unsigned long currentMillis, lastHeartbeat, lastBackDown, lastEnterDown, lastMouseDown;
 int mouseSpeed = MOUSE_BASE_SPEED;
 
 void setup() {

}

void loop() {
  if (Serial1.available())
    read_lin_bus();


  if (frame.get_byte(0) != SWM_ID)
    return;

  lastHeartbeat = currentMillis;
  
  // skip zero values 20 0 0 0 0 FF
  if (frame.get_byte(5) == 0xFF)
