Robo Relay Race

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Robo Relay Race builds on the skills learned in Basic Robo Race and introduces communication and coordination between robots. Robo Relay Race is meant as a combined team exercise. Each team will build a robot that is capable of completing the circuit on its own.

Mission Objective

Build the fastest team of two (2) robots to complete a closed circuit. Each robot takes turns running the course.

Race Rules

• The robot must pass an inspection before the race starts to ensure no construction rules have been violated. The robot team will have a chance to make modifications before the race starts.
• Both robots will be placed at the starting location on the track, with the Tail Robot behind the Lead Robot.
• When commanded, the robot drivers will press the green “run” button on both of the robots and the clock will start.
• The first robot must follow the path until it tags the second robot.
• After tagging the second robot, the robot must come to a complete stop and turn off its motors.
• A signal must be transmitted to the second robot to get it started.
• The second robot must follow the path until it tags the first robot.
• After tagging the first robot, the second robot must come to a complete stop and turn off its motors.
• Each team will build two (2) robots capable of completing the circuit on their own.
• The first robot may only signal the second robot using an infrared transmission, and after it first tags the second robot.
• The running time is taken from the time the first robot is commanded to start to the time that the second robot tags the first one and comes to a complete stop.

Robot Construction

• The robot must be less than 11 inches long including any extensions.
• The robot must be less than 10 inches wide.
• The robot must be programmed using RCX code programming.
• Once started, the robot must be completely autonomous.
• Teams may use any number of Lego sensors and bricks.
• The lead robot must have the RCX infrared transmitter facing forward.
• The second robot must have the RCX infrared transmitter facing backward.
• Neither robot may have sensors located in the rear.

Violations

Major Infractions

When a major infraction occurs, the robot must be restarted from the beginning of the track without stopping the clock.

• Once the robot is moving, there can be no human intervention until the robot completes the task.
• The robot cannot leave the track during the race.
• Losing pieces while the robot is running the race.
• If an error occurs and it appears the robot will not finish the race.

Minor infractions

Failing to come to a complete stop when returning home incures a 10 second penalty added to your time.

Premature starting of the second robot will incur a 50% time penalty added to your total time (i.e. Time to complete the race + 50% of the time to complete the race).

Determining the winner

The racer with the shortest time, after violations, is declared the winner.

In case of a tie, the tied contestants are allowed a run-off. The racer with the shortest run-off time is declared the winner regardless of their initial time.

Playfield

See the Track section for help building the track.

Materials

• 8-12 white bookshelves, approximately 10”x36”x1/2”. These can be obtained from any local building center.
• Black electrical tape, approximately 5/8” wide.

Construction

• Layout the bookshelves on a flat surface in any closed pattern.
• Lay a strip of tape in a smooth line in the middle of the boards.

Hints:

Use a semaphore to make the trailing robot wait for the lead robot.

Copyright (c) 2000, 2001 Chung and Engalan. Used by permission.