Making Software Useful

After I completed my dissertation a couple months back, I’ve switched over to working on the Pharos Project nearly full-time. Pharos is a fledging project aimed at creating a modular testbed for (primarily) wireless networking research. Basically, we get a bunch of robots to move around in a big parking lot and see if we can still get them to collaborate, even though they can’t alway communicate.

Monday was a big day for the Pharos project. We took 10 robots out to the Dell Diamond’s back parking lot and collected the first real, useful data. There were two main focuses for the mission: (1) how accuratly can we move along a predetermined path using GPS coordinates, and (2) how does distance effect the connectivity of the standard ad-hoc wireless network.

To answer the first question, take a look at the following picture. Here the red line is the track that we wanted the robot to follow. The purple line is the path that it actually took (according to the on-board GPS). The node started in the bottom left and drove to it’s first waypoint in the upper right. Then it visited each waypoint in turn, ending in the upper left. (It seems that maybe it started wandering around on it’s own for a while after it was supposed to stop)

Given that this is very preliminary data, it seems that this bot did a darn fine job of going where it was supposed to go.

To answer the second question, we had one robot sit still, and another drive past it several times. We measured the acheaviable throughput over the wireless network to find out just how far you have to go to disconnect. Well, it seems that you have to go about 80m. I wish I had the graph to show you, but it’s still under construction… in the mean time, here’s the mobility trace from this experiment:

I’m proud to say that my demo at Middleware 2008 went very well. It seemed that everyone understood both the basic tentants of the architecture and the actual implementation sitting on the table in front of them.

As murphy’s law dictates, the sexiest part of the demo (the Roomba) failed to work on demo day. I’ll be diagnosing this issue when I get home, but I now believe the servos make a better demonstation tool anyway.

For more information about the SEAP system, here is a list of other resources:

• A more detailed explanation of SEAP currently under review for a conference.
• The first SEAP (short) paper with a brief explanation of the technique
• Original Demo Proposal for Middlware 2008

My demo of the SEAP middleware architecture was accepted at Middleware 2008. I’ll be traveling out to Leuven, Belgium in December to give the demo.

I’m excited to give this demo for a couple reasons. First, I think it’s going to be a really interesting demo to interact with. The devices and code are all going to be right out on the table to play with. Second, Middleware has two dedicated slots for demos, so there’s a good chance to meet people.

If you’re going to Middleware also, be sure to check out our lab’s paper on Adaptive Milddleware to Support Delay Tolerant Networking in the ARM ‘08 Workshop.