It looks like MEDC is going to see the return of the conference SumoBot competition
that made an appearance at EDC 2004. This should be no surprise to anyone that
went to last year's Embedded Developer Conference since the competition was one of the social
highlights of the event.
Perhaps you are asking some of the same questions that many of us were
wondering at the
time... "What is a Sumobot Competition?", "Why would I
care?", "How do I enter?" and then "What the heck do I do
next?". I thought I might try to briefly describe some of what went on
at last year's event to help answer a few of these questions and perhaps help get you started on your own
Sumobot experience and maybe even a new hobby obsession.
Entering a Team
There was mention of the Sumobot competition in the marketing marketing
materials that led up to last year's EDC and there were emails encouraging us to
"prove our worth" in the Ultimate Architect Contest. 
The
materials mentioned that the idea was to build the best Sumobot and that the
competition would be limited to twenty teams. So, not being familiar
with what exactly a "Sumobot" was and not realizing that it was a very
particular type of robot (that came in kit form), I pictured something like the
robot wars that you see on cable television. It sounded like it was going
to be fun to watch, but I personally didn't have the time to architect a menacing
mechanical robot munching machine and I didn't have a team of engineers at my
disposal that would join my team. I arrived at the conference unregistered for the
competition, expecting teams from colleges or engineering firms to make up the
competition roster. During the keynote presentation, we were shown the
SumoBot "Kit" that each team would be given and it was mentioned that
there were a few openings left and still time to enter. Well, when I realized
that the kit came with all of the necessary parts, plus instructions on how to
put it together, and that these little beasts were programmable... that changed
everything. At the next break, I high-tailed it over to the registration desk and
put my name down, if for no other reason than the chance of going home with a programmable
robot kit.
The Gear
The
entire kit came in a moulded plastic package that contained over sixty
individual parts and pieces and we were provided with a package of "AA" batteries to
give it life. Along with the wheels, servos, screws and wires was a detailed
manual (see sidebar for link to PDF version) that covered everything from step-by-step assembly of the
robot to the basic programming required to compete, as
well as detailed specifications on the Sumo Ring and the rules of engagement.
The company that distributes these kits estimates that it will take about an
hour to put one together, however, I recommend that you allow a little more time
as it took some of us almost an hour to open the rugged, plastic, vault-like
packaging. Also, others literally spent an afternoon shopping for bot accessories
while looking for that competitive edge.
The Ring
Sumobots use light sensors to detect the boundaries of the ring and to know
when to turn 
around if they are getting too close to the edge, so the regulation
Sumo ring consists of a circular black surface with an outer white ring, all
crafted to very specific dimensions. Beyond the edge of the ring is an inch high
drop that represents the end of the match for the first bot to succumb to it. If
you look closely enough, you will also see two starting lines that competitors must be
behind when the match begins.
The Objective
The main idea of a Sumobot competition is to stay inside the ring and, like
a more traditional sumo match, your goal is to force the other competitor out of
the ring. 
So, from a
programmer's point of view, it is important to be able
to detect both the edge of the ring and the opponent. As shown in the
manual, competitors are provided with basic competition code that will read the
light sensors to detect the lines at the edge of the ring and code that will
read the IR sensors while seeking out and hunting down the opposing bot.
Since both teams start out with the same hardware and software, the main
strategy involves enhancing the basic competition program so that your bot can
out sumo the other bot. The brains of this little bot are housed in a
BASIC Stamp which is a small module from Parallax with their PBASIC interpreter
on it. If you have done any BASIC programming, you won't find programming this
BASIC Stamp too different. There was lots of buzz last year about how cool
it would be if there were a .NET version of the bot. I haven't heard if we
will see SumoSPOTs at this years conference yet, but check out the .netcpu
mentioned in the sidebar, if the idea intrigues you. After custom programming, the fun doesn't stop there. Many of
the competitors last year also looked for ways to enhance the hardware side of
the equation as well. For example, one theory was that rubbing the bots
wheels with alcohol swabs purchased at a local electronics store might improve traction
in head-to-head combat. Another competitor assembled their bot with the
PCB SumoBoard upside down to create a more streamlined warrior. Other teams tried
various creative ways, sometimes compliant with the rules, sometimes not, to
enhance their chances of winning. The most controversial entry in last year's
competition was from the team with the guy who presented the Bluetooth session at the
conference; their bot had a mysterious blinking "sail" on top of
it.
Construction and Customization
So, here are some things to think about if you plan to build a bot in this
year's competition. Last year, when competitors started to build their bots, tools
and accessories were in big demand. The solder points on the wires that
connected to the battery pack proved to be very fragile and this particular part
(#753-00001) got
swapped out at the parts desk until there were no longer any good ones
left. The search was then on for a soldering iron which, if I recall
correctly, came from the maintenance staff of the conference center. LEDs
and sensors occasionally got lost and broken, so they were also popular items
sought out at the parts
counter. 
The parts counter was basically the leftover parts from one or two DOA
kits. As a matter of fact, I started with one of those DOA bots myself. I had the
whole thing pretty much assembled, only to find out that it was missing a couple
of essential jumper pins on the main board that seem to have just never been
soldered on in the first place. By the time I had finished building my
second bot, I was really starting to get the hang of assembling these things, but you may want to schedule a
detailed materials check, including a close inspection of the main circuit
board, as one of your first steps to avoid a similar experience. Some of
the teams hit the local Radio Shack looking for additional sensors and gadgets
to soup up their little Frankensteins. Detection of the opposing bot is
done with stereo IR emitters that are plugged into the bots breadboard and
constantly send out an IR signal. Along side of the emitters are two IR
sensors that detect when the outgoing signal hits something and comes bouncing
back. When a reflecting IR signal is detected in either the left or right
sensor, it is time to chase (or run from) the other bot. Perhaps you can
think of ways to make your IR detection code, or even the hardware, more
accurate or responsive. However, at last years event, the deciding factor
in most matches usually came down to the bots' relative positions when the
pushing began. So, the one thing I would recommend for you think about, if
you really seek victory, is how you can code your bot to be in the right
position when all the shoving starts.
I certainly don't recommend that you attempt
to pack anything in your suitcase that will cause you delays or alarm the
security at the airport on your way to Las
Vegas, but you may want to plan ahead and bring a few strategic things to help
in your quest to dominate the Sumo ring or dress up your bot. It is good to keep in mind
that showmanship really adds to excitement and team spirit as well. Some of the best
dressed bots may not have won last year but they attracted lots of
attention.
Last year, few people knew what to expect when it came to signing up for
this
competition, so it was still possible to sign up at the last moment.
However, those that did sign up had a blast and many of those who didn't enter wished
they had. Don't be intimidated by thinking that building a Sumobot will take a
degree in robotics and a team of rocket scientists, because it doesn't.
This is a fun, hands-on activity to participate in that will make your trip to
MEDC even more enjoyable and memorable and you might just learn a thing or two
about the cool area of robotics while you are at it, even if you don't make it
into the finals. Connect up with a few friends and book a team early before the
spots are all taken. Even if you don't compete, this is a must-attend conference
event where you can go out and cheer on your favourite bot and release a little
energy after sitting quietly in conference rooms all day long.