Motor control.launch

<!--
  Launcher for Phidgets differential drive wheel motor controller.
  -->
<launch>
    <node pkg="phidgets" type="motor_control_hc" name="motor_control_hc" respawn="true" output="screen">
        <!-- for now disable odometry feedback for PID by providing a bogus topic -->
        <param name="odometry" value="disable" />
    </node>
</launch>