logdebug not working on arduino/rosserial

edit

I've spent the last day os so investigating this sporadically but I'm no closer to finding an answer, any insights gratefully received :)

My robot has a Raspberry Pi 3 as central control unit with two arduinos running as rosserial nodes for inertia measurement/compass/etc. and radio control/motor control/measurement respectively. Everything is working fine (and I love the ROS architecture, it's made this project a pleasure to work with !).

I use roslaunch to bring up the nodes:

<launch>

<node name="ROS_IMU" pkg="rosserial_python" type="serial_node.py" output="screen">
        <param name="port" value="/dev/ttyUSB_IMU"/>
        <param name="baud" value="57600"/>
</node>

<node name="ROS_ECM" pkg="rosserial_python" type="serial_node.py" output="screen">
        <param name="port" value="/dev/ttyUSB_ECM"/>
        <param name="baud" value="57600"/>
</node>

<node name="ROS_GPS" pkg="gpsd_client" type="gpsd_client" output="screen">
        <param name="_port" value="2947"/>
</node>

<node name="ROS_CCU" pkg="storm" type="ROS_CCU.py" output="screen" />

</launch>

All logging works on the CCU in python, where I set the log level using

rospy.init_node('ROS_CCU', log_level=rospy.DEBUG)

My problem is that I can't find an equivalent for the arduinos, and in fact http://wiki.ros.org/rosserial/Overvie... suggests that I can just use loginfo()/logwarn()/logdebug() etc. without setting the log level. However while loginfo() and logwarn() work, and the messages appear in the launch window, logdebug() doesn't - well nothing appears anywhere.

Any ideas ?

Thanks,

David