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Hitting the wall took on an identity apart from the NASCAR circuit Dec. 6 when
13 freshman computer science students went Lego-to-Lego in a two-heat soccer
match before a small but vocal crowd of spectators at Sitterson Hall.
Injuries were life threatening. Arms and legs were lost but reattached. One
player lost consciousness from exertion but recovered enough to continue play
when its load was lightened after an emergency double amputation.
The playing field consisted of a white, four-by-eight sheet of plywood bounded
by eight-inch walls. At each end was a goal, and a dark gray line ran the
length of the field, goal-to-goal. Fifteen black Ping-Pong balls were randomly
scattered on the table. Actual play resembled a demolition derby as much as
anything else.
Players competed singly against a three-minute clock, beginning play at one end
of the field. The idea was to get the most balls into the goals, and high
scorer after two heats was the winner.
Every time a player got stuck, usually by running into a wall and failing to
navigate away, time was called. The player was assessed a 30-second penalty in
which its coach (or coaches) had time to regroup (or reattach as frequently was
the case), and play continued.
Of course, the players were really robots, all constructed from Lego Mindstorms
kits, and their boxy brains were RCX computers clad in black and gold plastic
Lego uniforms.
The Comp-006 students, in pairs or as individuals, designed, programmed and
constructed the robots -- often by trial and error, the students admitted. For
example, Diana Suryakusuma called her player "Fifty-Fifty," because that's
exactly the odds she gave it for performing.
Sports metaphors abounded from the start of the competition. Initially set for
Dec. 4, the match was rescheduled for Dec. 6 when the self-professed Umpire
Lastra, actually Anselmo Lastra, associate professor of computer science,
punted on his original game plan once he saw the students' problems with
fielding their players.
Once Lastra announced a time out and revised guidelines, the teams had about a
day and a half to regroup, redesign and rebuild.
In spite of the fits, starts, stalls and crashes, the freshmen used great
ingenuity, composure and problem-solving savvy. "It's great to see the
creativity and enthusiasm that the students showed," Lastra said, who during
the competition was the players' biggest supporter.
The goals of the class as stated on the syllabus were to learn the basics of
computers, input/output and sensors; exercise, learn and enhance the craft of
design; and improve communication skills through presentations, writing, web
pages, images and video. "They certainly had a good time making the robots,"
Lastra said, "and I think they learned something about building real-world
machines along the way."
Most of the Lego players used sensors in one form or another. That dark gray
line running the length of the white playing field was actually a target for
some of the sensors, as were the black balls.
Louis Padgett's "Scorpion" had a grand game plan. With its two jointed arms
spanning the width of the field plus a long tail, Padgett's goal was to grab as
many balls as possible in one aggressive, initial shimmy down the board.
Scorpio was programmed with a light sensor that oriented itself to the dark
line, but in actual competition it looked out of balance and veered to the
right.
Scorpion scored five goals in its first sweep. At the beginning of its second
heat it seemed to have run out of speed, and that's when Padgett
unceremoniously started pulling off Lego leg parts to give it a little less
weight and more oomph. But the thing immediately threw a wheel on its next
attempt and ended out of the top three finishers.
Fifty-Fifty, which was coached by Suryakusuma and Zack Underwood, sported a
nifty flexible front bumper that could scoop balls up and run all the way into
the goal with them as the bumper ingeniously collapsed. Unfortunately, it lost
a light sensor early on and took a penalty time out, and, when it came back
out, its right tractor tread immediately stalled so it started moving in a slow
circle. No points.
"Midnight Wonder," designed by Josey Bridges and Ebony Spivey, was better at
using its sensor to catch balls than to find the line. But at the end of the
first round, it had shot in two goals, using a dribbling motion. On its second
try the spectators watched in helpless frustration as it zoomed toward a ball
but immediately switched directions inches before catching it. "Nooooo," the
crowd yelled.
Yin Song and Tristan Willoughby built "Ball Grabber," and it grabbed the
first-place prize which turned out to be an impressive engraved Plexiglas
trophy.
Ball Grabber was another player with a broad grasp. Its light sensors were in
its "hands" and came into play once the arms had corralled most of the balls in
its first run. After that it hit the wall, backed up, and continued swiveling,
looking for balls. At the end of its first heat, Legos were beginning to fall
off, but it still scored a 12.
On its last try, Ball Grabber started losing Lego parts again, but once one of
the students took a penalty to cast the pieces aside, the Grabber went on
undeterred to score the game high of 13 goals.
Other students taking part in the demonstration were Gabe Gales and Carlos
Alves, whose "SOTM 2" (Spur of the Moment) took second place; Junji Shibata and
Jason Lucas, whose "D.U.I." took third place; Terry Aringe and "Stupid
Machine"; and Ralph Hunter and "Ralph."
For an instant replay of the competition in pictures, refer to the class's web
page at http://www.cs.unc.edu/~lastra/comp006/
The class is one of Carolina's first-year seminars, designed to enhance
freshman students' academic experience as part of the University's Intellectual
Climate initiatives.
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