The public is cordially invited to:
2007 Rice LEGO Robot Contest
December 2, 2007
Auditorium, Duncan Hall
Games and Winners
Year 2007 Game: Robo Basketball
Two robots compete to earn
the most points within a 90 second game. The robots first have to get
balls from dispensers at the end of the board, and then earn points
by depositing them in one or more goals located on the game board. The
various goals have different levels of difficulty and point values.
They can earn bonus points by shooting balls through a hoop goal from
the other side of the table. Good strategy, skillful ball handling,
and especially reliability will be important.
- Fame, Glory, and Bragging
- The winning robot will
be kept for display next year, so you do not have to disassemble it.
- A modest gift for winning
team members; some assembly may be required.
- The contest is for motivation,
for demonstration of your accomplishment, and, most of all, for fun.
Your grade in the course does not depend on your robot's placement
in the contest. Top
Board, Objects, & Rules
Game Board & Rules
The game board is a 6 foot
by 8 foot flat surface. The red stars represent starting lights embedded
in the board; a robot starts at each location, just in front of its
hoop goal. The ball dispensers (BD) are at the far end of the table.
There are two additional goals for each robot, one at the edge of the
board, one in the center. At each end of the board, on the center line,
are four 3" high posts or bollards extending 12" out into
the playing area. One half of the board is painted flat black and has
white lines to aid navigation; the other half is painted flat white
and has black lines. The lines, indicated in the drawing by dark dashed
lines, are 3/4 inch wide. The board has 5 inch high walls at all four
sides; the inner side of all the walls are painted flat white. The
drawing of the board is reasonably to scale, but the official dimensions
are those of the physical game board. Since the board is constructed
in parts, there may be small surface and wall misalignments; these should
be less than 1/8 inch.
- The balls are Hasbro Ballzooka
Nerf Ballistic Balls, approximately 1.73 inches in diameter, with
a slightly fuzzy, flat yellow surface. The balls are light weight,
slightly resilient, and bounce reasonably well. All balls are inert
and have identical mechanical properties.
- The two ball dispensers
each contain 7 balls at the start of the game. Balls are released
by illuminating a light sensor located 4 inches above the table surface,
in the wall at the edge of the table. When the sensor is activated
the dispenser will release 4 balls. After a delay of 3 seconds, the
dispenser may be triggered again to release 3 more balls.
- Balls will be dispensed
from a height of approximately 6 inches above the table surface, at
the edge of the table, directly above the activating light sensor.
- Although each ball dispenser
is located on a particular side of the table, no dispenser "belongs"
to a particular robot, and either robot may get balls from either
dispenser; all balls have equivalent status in the game for each robot.
- The balls may not be punctured,
altered, or modified in any way.
goals are located on the sides of the board and consist of a 12
inches wide by 7.5 inches deep bin. The floor of the bin is at the
table surface. The walls of the bin are 4 inches high.
goals are centered on the table, straddling the black/white division
of the table. Each goal has a holding area of 5.5 inches by 23 inches.
The floor of the bin is about 1/8 inch above the table surface. The
common wall of the two goals is 3 inches high, the opposite wall is
1.5 inches high, and the other two sides are 2.5 inches high
Two 12 inch
diameter circular hoop goals are located at the end of the
table, 18 inches from the side walls. The plane of the hoop is perpendicular
to the table surface and at the edge of the table. The center of the
hoop is about 12 inches above the surface. An IR beacon, shining out
toward the center of the table, is located below the center of the
hoop, about 5.5 inches above the table surface. The beacon is modulated
at either 100 Hertz (white side) or 125 Hertz (black side) with a
40,000 Hertz carrier. The robots can use these beacons to locate a
particular goal from a distance.
The back of the hoop is made out of net so that balls projected into
the goal will tend not to bounce out. A ball remaining in the hoop
goal/net at the end of the game is worth 5 points. A bonus of 5 points
is awarded if the ball is shot through the hoop as described under
- The two robots for each
game, and the side they will start on, will be chosen by random from
those robots that have not played in the current round. (See Format,
below.) This information will be announced during the previous game
so teams may prepare their robot. The starting position of a robot
defines its side of the table for scoring purposes. The contestants
will have 60 seconds to place their machines on the game board from
the time the judges call them to set up.
- During the Set Up time,
the start lights will be ON to aid in robot alignment. When both teams
are ready, and/or the preparation time is over, the start lights will
be turned off and the teams will have a few seconds to prepare their
robot (typically by pushing the Choose button) to start the game when
the start lights come on again.
- The game will be started
by the judges turning on the starting lights, located in the surface
of the table, for the first two seconds of the game.
- False Start Rule: A robot
that fails to start as expected will be awarded a False Start, and
the round will be repeated immediately. Two False Starts constitute
a loss, and the robot will be removed from the table. The remaining
robot will be allowed to play without opposition.
- The powered portion of
a game will last 90 seconds. Software will be provided to cut off
power at the end of 90 seconds, and any machine that continues to
supply battery power after 90 seconds will lose the game.
- The game ends when both
robots and all balls come to rest.
- The judges will propose
to terminate a game early if neither robot appears to be making any
The appropriate number
of points, 1, 3, or 5, will be awarded for each ball that remains
in one of your goals at the end of the game. It does not matter which
robot caused the ball to enter your goal. A robot's goals are those
on the side of the board from where it starts, e.g. the goals for
a robot starting on the white side of the board are on the white side
of the board. The coloring of the goals on the diagram
indicates this relationship.
A bonus of 5 points will
be awarded for shooting a ball into your hoop goal at the end of the
table. To receive the bonus points, your robot must cause a ball to
go through the hoop while all its contact points with the board, wheel,
skid or tread, are behind the centerline of the game board (away from
The machine with the most
points wins the game. If there is a tie, the judges will decide the
winner based on which robot that has more balls nearer to its goals,
or declare a double win. If no points are scored a double loss will
be awarded. Top
Contestants should ask the
instructor about possible designs or strategies that may be questionable
under any of the rules.
Contest rules and procedures,
or even the game, may have to be altered during the semester. As much
notice as possible will be given.
The judges are the instructor
and any others he may designate.
The judges may alter or eliminate
any rule, or add rules, at any time.
The judges will decide any
discrepancies in the contest play.
All decisions of the judges
are final. Top
The contest is a double elimination
competition held over two days. On the first day a machine must "beat
the brick" win a game played against an inert opponent (or
no opponent) in order to qualify for the competition. Qualified
machines will then play one competition round, arranged by lottery. The
result of these exhibition games will be recorded but not counted for
the main contest. At the end of the first day, the qualified machines
will be impounded.
The main competition will take
place the second day. For each round of the contest, two robots will be
matched by random drawing for each game, so that at the end of the round
each robot will have a recorded Win or Loss. Robots with a total of two
Losses will be removed from next round and the contest. Rounds are played
until only one robot remains: the Winner. For any game the judges may
declare a double loss, a double win, or no result, as appropriate.
See Period of
Play, above, for detailed game rules. Top
Teams are encouraged to seek
advice and help from any source, but the design, robot construction, and
control code must be exclusively their own work.
All entries must be solely
controlled by their onboard computer. There can be no human intervention
once the game begins. A robot that is touched by a team member during
a game will be disqualified for that round. Also, team members touching
the game board during play risk disqualification of their robot.
Teams may qualify only one
robot, and only that robot may play in the final round. Significant changes
in robot structure or code following qualification must be approved by
Contestants may not alter the
essential structure of their entry, or add/subtract significant parts,
once the competition has begun, but may repair broken components between
rounds if time permits.
Teams may possess only one
RoboBoard controller at any one time.
A robot cannot be designed
primarily to destroy the physical structure of its opponent. In particular,
machines are not allowed to destroy their opponent's microprocessor board,
or sensors. However, blocking, pushing, turning, overturning, or confusing
an opponent is allowed.
No parts or substances may
be deliberately dumped, deposited, or otherwise left to remain on the
game board surface. A machine that appears to have been designed to perform
such a function will be disqualified. Pieces which accidentally fall off
robots may be removed from the board during a game by a judge at his discretion.
No adhesives or sticky substances
(such as on tape) may be applied to any part of the game board or to a
game piece (ball, block, goal, other robot, etc.)
Any machine that appears to
be a safety hazard will be disqualified from the competition.
Your robot must be constructed
using the parts in your kit, with a few exceptions as detailed below (in
particular see The $15 Rule). All kits contain exactly the same components,
except that some LEGO parts may be colored differently in different kits.
You may request additional sensors, wire, wheels, gears, and other small
parts as required. After mid-term recess, the instructor will entertain
requests for extra LEGO parts necessary to implement unique design features.
Some parts in the ELEC 201
kit are considered tools and may not be used on the robot. Examples are
the large plastic parts container, the small rectangular parts container,
the soldering iron, the sponge, etc. If there is any question about whether
an object is a ``kit part'' or a ``tool part,'' ask the instructor.
The dimension of the machine
may not exceed 12 x 12 x 12 inches high at the start of each round. Entries
may, however, expand once the round has begun. The start light sensor
must be within 3 inches of the geometrical center of your robot.
Only LEGO parts and connectors
may be used as robot structure. All structurally separate parts of the
robot must be connected by LEGO beams, plates, axles, etc., specifically
not by rubber bands, LEGO chain links or track. Rubber bands may
be used to provide stored energy, but not as primary structural elements
or as linking elements between LEGO parts. Top
LEGO pieces may not be glued
together, nor altered in any way, with the following exceptions:
The LEGO baseplate may be altered
LEGO pieces may be modified
to perform a function directly related to the operation or mounting of
a sensor or motor. For example, holes may be drilled into a LEGO wheel
to make an optical shaft encoder; sensors may be glued to LEGOs.
Rubber bands may be glued to
LEGO wheels or gears to increase the coefficient of friction.
A maximum of five (5) LEGO
parts may be cut or modified at will, or glued to non-LEGO parts other
than sensors and motors. Top
Cardboard, other paper products,
and tape may be used to create optical shields for light sensors, to line
bins, or to form ramps or other elements that are not primarily structural.
Purely decorative items may
be added at will, within the size limits and good taste.
Cable ties may not be used
for structural purposes.
String may not be used for
Tape may not be used for structural
Wire may only be used for electrical
purposes, not structural.
No lubricants may be used.
To encourage creativity, contestants
may spend up to $15 of their own funds for the purchase of additional
components used in their design. The following conditions apply to all
No single part may cost more
Resistors rated less than 1
watt and capacitors valued less than 100 microF may be used freely, without
counting toward the $15 total.
LEGO parts not issued in the
standard kit but obtained outside of class, must be documented under the
The following components, categories
of components, or varieties of circuitry are disallowed: any additional
batteries; motor driver circuitry, including relays, power transistors,
or any other replacements or modifications to the standard motor driver
All non-kit parts used must
be documented in a short report that includes a description of the part,
or schematic of any added circuitry, and receipts for parts purchases.
A part that has been obtained through means other than retail purchase
will be assigned a value by the instructor. This Extra Parts Report must
be signed by the instructor prior to the first round of competition, and
should be kept by the team in case of a challenge. Any machines found
with added parts that have not been documented in this fashion will be