   // Update ROS
   ros_nh.spinOnce();
   
-  // If have not received cmd_vel messages in threshold time,
-  // something is wrong, stop the robot.
+  // If no cmd_vel messages withing threshold time, something is wrong, stop the robot.
   cmd_vel_timeout_stop = (current_time.toSec() - last_cmd_vel_time.toSec()) > CMD_VEL_TIMEOUT_THRESHOLD;
   if (cmd_vel_timeout_stop) {
     motor_left_speed = 0;

  timer.every((1.0/publish_magnetometer_freq_hz) * 1000, doPublishMagnetometer);
  timer.every(BLINK_DURATION, doBlink);
  
  current_time = ros_nh.now();
  previous_time = current_time;
  last_cmd_vel_time = current_time;
  last_odom_publish_time = current_time;
  last_encoder_read_time = current_time;

double y;
double th;

char ros_odom_header_frame_id[] = "/odom";
char ros_odom_child_frame_id[] = "/base_link";

