Line Follower Contest – PPE’13

This page will be for a Line-Follower contest at the Official PropellerPowered Expo – 2013.

The expo was wonderful, and the contest went pretty well.  Here are the results:

Line Follower –
– In first place, with a best time of 9.7 seconds, was Toadblue, owned by Roger Goff
– In second place, with a best time of 18.2 seconds, was Thing1, owned by Chris and Abby Wardell
– In third place, with a best time of 46.4 seconds, was S2, also owned by Roger Goff

For the trivia collector: Chris and Abby’s robots were named after Thing1 and Thing2 from the Cat in the Hat (  Thank you Abby for those imaginative names.

This will not be the actual course map, but it should be close.  The important parts are a start/finish crosspoint (the ‘bot can use this cross line to determine when to quit,) a hairpin turn and a slalom course.  This will test all of the functioning of an entry-level line follower robot.

Rules: We will be following a basic line-following program.

Overview – This contest tests a builder’s ability to construct a robot which can follow a simple line course.  The primary objective of the contest is speed, with a secondary objective of accuracy.

Course Construction – The Basic Line Following course is constructed using large sheets of white poster-board, or foam-core board.  These sheets will be taped together with white tape, to form a large course platform.  The course will be laid out with black electrical tape. The contestants will not know exactly what the course will look like before the day of the event, but the course will consist of a start/finish cross line (the ‘bot can use this cross line to determine when it has completed it’s run,) and zero or more of the following:  straight-aways, hairpin turns, 90-degree sharp turns, 90-degree curved turns and slalom sections.  There should not be any branching of the course, or three-dimensional tracks (bridges, etc.) at the beginner level of the line following contests.  You can look at the diagram above for a sample course with some of these items.

Robot Construction – Each robot must fit on the platform (the course will be designed to accommodate robots of the same size as the Parallax Sumo-Bot.)  In addition, robots may not intentionally damage the platform in any way.  Since this is an expo honoring the Parallax Propeller microcontroller (,) each robot must use a Propeller as it’s main control unit.  You can find a lot of information at Parallax’s Propeller site:

Contest Procedure – Each robot is given up to three attempts to run the course, with a minimum of a 5 minute “tweak time” between runs.  Each run will consist of 3 laps around the course.  The starting position is the cross-line, the robot will be placed just before the cross-line.  The lap time will begin when the robot first crosses the starting line and will end when the robot crosses the line again.  The builder may choose to run the robot in either clockwise or counter-clockwise direction, and may choose a different direction for each attempt.

The elapsed time for each run will be recorded.  Added to this time will be penalty seconds assessed during that run.  The lowest total time (with penalties) of the three runs will then be recorded for the robot’s score.  In other words, your worst scores will be thrown out and only your best (lowest) score will be counted.

Should the robot lose the line and require human intervention to reacquire it, the robot must be placed 4” – 6” prior to the point where it lost the line.  At no time is a robot allowed to skip a portion of the course.

Scoring – Each run will be scored based on the base time for the run, to which any earned penalty seconds will be added. Penalties are assessed as follows:

Reason for Penalty Seconds Penalized
Losing the line (when no part of the body of the robot is over the line)
Robot reacquires the line with no help 2
Robot reacquires the line with human assistance 5
Robot reacquires the line with the use of human assistance twice within 6” 10
Breakdown (refusing to run for any reason) End of attempt
Requiring more than 10 human interventions in a single run End of attempt

In the event of an End-Of-Attempt, that score will be recorded as a zero (0) and will not be included.  The robot will receive the lowest time score of the remaining runs.  In the event of all three runs ending with an End-Of-Attempt, the robot will be disqualified.

Robots are ranked by number of seconds (plus penalties) with shorter times ranking higher.  In the event of a tie score, the robot with the fewest penalty seconds added shall be declared the winner.

I have decided to delete the category for the “Robot reacquires the line with the use of a barrier”, since there will be no barriers on this course.  In addition, I also lowered the penalties for some of the loss-of-line incidents.  This will make the scores a bit lower for those who’s robots have troubles keeping the line.

Here is a copy of the score sheet in PDF format: Line-Follower Robot Contest.  Take a look at this sheet and let me know of any change suggestions.

More details as we come up with them.

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