Bus active for about 36 hours with full nav, video, ultrasonics, etc publishing and subscribing. The unit is positioned such that when someone passes by within range of 300mm it will announce "Excuse me, you are nn millimeters too close to my feet" and/or "Excuse me, you are nn millimeters too close to my head" so its easy to confirm the bus is still operational just by walking by, or if the cat is becoming petrified by walking by the lower ultrasonic and causing it to speak only of its 'feet'. The subscriber is listening to 'range' topics from nodes ardrone and robocore (Parrot and floor level ultrasonics) and doing a simple check which results in the VoxHumana speech module activating or not. Occasionally, an error from the RS232 comms between lower ultrasonic->arduino->core process->ROS allows a zero to creep through so you get "Excuse me, but you are zero millimeters too close to my feet". Passive debugging tools are neato! I did lose the Edamax wireless USB dongle that talks to the ARDrone boards from RPi 1, perhaps from heat. It gradually degraded such that errors from the nav thread were popping up in the form of broken DatagramSockets so I added code to reconnect and tickle the port under those conditions but after replacing the dongle, few broken sockets. Also had to work out all the static persistent routes for bootup.  Serendipitous security was achieved when I moved the master registration server to the second RPi. RPi 1 is not set up to source route packets to RPi 2 so its not possible to connect to the master from outside of RPi 1. Nobody can hijack your 'bot by connecting wirelessly and spinning up a ROS node. About the most that could be done is to issue disconnects from the wireless network or cut off video or sensor data. So we are finally good to go with a stable, open platform and can move on to the really interesting part of this project.