   nh.subscribe(sub); // Start subscribe the "steer_ctrl" topic.
 }
 
-void loop() {
+void loop()
+{
   nh.spinOnce(); // Check topic and if change it, run the call back function.
 }
 

ros::NodeHandle nh; // The nodeHandle.
ros::Subscriber<geometry_msgs::Twist> sub("steer_ctrl", &steerCb); // Set subscribe the motor_driver topic.

void setup() {
  /* Set pins Mode. */
  for (int i = cw_plus; i < ccw_minus + 1; i++) { // 3: CW+, 4: CW-, 5: CCW+, 6:CCW-
    pinMode(i, OUTPUT);
    digitalWrite(i, LOW); // Default pin status is LOW.
  }

 * @author "Yusuke Doi"
 * @param msg This param is msg object of the motor_driver topic.
 */
void steerCb(const geometry_msgs::Twist& msg)
{
  int time = msg.angular.x * 10;
  if (msg.angular.z < 0 && time > 50) gen_pluse(LEFT, time); // Minus mean CCW or right.
  else if (msg.angular.z > 0 && time > 50) gen_pluse(RIGHT, time); // Plus mean CW or left.
