When LEGO meets Sumo
Running a SuGO tournament
by PHIL MALONE
When I moved to Garrett
County (a rural community
in western Maryland),
I really wanted to start
a robotics club. I’d been
working in underwater
robotics for about 20
years, and I figured it was
time for me to give
something back to the
community in the way of
fun technical challenges
for the area kids.
Underwater robots are tough to build (water and electricity just don’t mix), so I decided that
Sumo robots were the perfect place to start.
The Inspiration
After experimenting with several Sumo kits and even
designing some of my own bots, I realized that traditional
Sumo competitions require some technical expertise that I
couldn’t expect from the kids I wanted to attract (yet). I put
the idea on the back burner for a year while I mentored a
couple of area FIRST LEGO League (FLL) teams, and helped
out in some LEGO tech camps.
LEGOs Rule!
When my desire to start a local competition resurfaced,
I realized that I wasn’t utilizing an abundant resource in my
area, namely LEGOs. It turned out that two area teachers
“Chuck” and “Arlene” had been accumulating all kinds of
the coolest LEGO parts and RCX Bricks for years and they
loved seeing kids explore LEGO machines. So, the idea for a
LEGO/Sumo ’bot was hatched.
Anyone who’s tried to build a LEGO/Sumo bot
probably knows that it’s tough getting one to fit into the
existing Sumo size classes. The RCX Brick (the original LEGO
brain) is just shy of the mini-Sumo class size limits, so by the
time you add motors, wheels, and a line sensor, you end up
with a very top-heavy robot.
Plus, until recently there was no easy way to add vision
to the RCX, so the robots just run around hoping to get
lucky and run into their opponent. For a Sumo bot to really
be competitive, it needs to be able to detect its opponent,
but LEGO doesn’t have a simple sensor that can be used to
decide which way to turn.
Since I’d used Sharp’s GP2D12 IR range sensor on my
other Sumo bots, I wondered if it could be adapted to the
LEGO RCX. The best way to find out was to see if anyone
had already tried, so I started Googling. First, I found
Andreas Peter, who had developed a fancy Sharp interface
56 SERVO 11.2008
