Racer

January, 2011 – April, 2011

I convinced my daughters Girl Scout Troop to participate in the 2011 National Robotics Challenge in Marion, Ohio.  They were eager to participate, so we met twice per month over a period of 4 months to build and test the robot.  The event I selected was the non-tactile maze.  I was surprised to see that in past years, they often didn’t give out all three (1st, 2nd and 3rd place) awards for the Elementary School age group.  Hmm.  Did that mean that other entries weren’t completing the course, or that there was low interest in this age group?  How hard could it be?  I felt confident that I could help them build a winning robot.

I started by buying a Parallax BoeBot kit and assembling it myself.  I also wrote the code and tested the robot to make sure the design was good.  I build a full-scale replica of the maze for testing – this ended up being key to our success.  I then tore it all down and wrote up some instructions.  I designed the bot to use the following:

  • 3 Sharp IR range finder sensors
  • 3 LEDs for feedback on the status of the range finders (illuminate if you sense a wall)
  • 2 continuous rotation servos
  • A buzzer for feedback

It was a simple design, and a good platform for learning.  When meeting with the girls, I insisted that they perform every step on their own.  I gave them guidance and instruction, but they assembled every last piece of the robot.  I then guided them in plugging in all the electrical components into the integrated breadboard.  Finally, I guided them through an exercise where they documented the required logic of the robot.  I helped them convert it to pseudo code, and then helped them convert it into actual pBasic code.  After some hard work, we were ready to test.  I worked with the girls to show them what to watch for, and how to tune the robot to meet their needs.

Finally the robot was build and tested.  The girls insisted on decorating the robot.  They voted on a theme and a name – they called it “Racer” since the idea was for it to get through the maze FAST!  They voted on the theme of a cheetah since it embodied the attributes they were seeking.  We hot-glued a Styrofoam half-sphere onto the front and gave it a paint job.  I had to negotiate heavily with them to avoid any decoration that would interfere with the sensors or electronics.

The day of the event came and our troop got to miss school to drive out to the competition.  It turned out to be a hurry-up-and-wait situation, so we spent time visiting the vendor booths and checking out the other events.  This was my first robot competition, so I was really excited.  We were given 3 attempts to go through the maze.  Each time the robot touches a wall, there is a time penalty.  The idea was to get the fastest time by completing the maze with minimal touches.

I was surprised to see that there was a LOT of competition.  I think the judges felt rushed to get through the queue of people to complete the event in time.  I found them to be a bit rude, and not at all embodying the spirit of learning that I was expecting.  Before our first run, I had a chat with the judges and offered to let them discuss the robot design with the girls.  They reluctantly agreed and the girls were well-prepared to explain all the details of how they built and tested the robot – they did a GREAT job.  On our second attempt through the maze, we completed with a good time and zero touches.  The girls were going crazy!  They were chanting “Racer!  Racer!  Racer!”  – we drew quite a crowd.  We were not planning to spend the night in the area, so I begged the judges to let me know how we placed.  I learned that we were to be awarded the Bronze Award – the girls were so excited (and so was I)!  We drove home and back the next day to participate in the award ceremony.  The girls were called up on stage to receive their award to the wild applause (and chuckles) from the mostly-older audience who thought they all looked cute in their uniforms.

Since it was my first robot competition, I took time to reflect on how I could do things better next time:

  1. Building a replica of the maze was a major help in testing the robot.  Most of the other contestants did not, so they were doing fine-tuning before and during the event.  We walked in with a well-tuned robot, so we could just relax and enjoy the event.
  2. The Parallax BoeBot platform was not well-suited for this project because it did not have the required analog-to-digital converter.  I had to do an unnatural thing with a capacitor which was adversely impacted by temperature and resulted in erratic test results.  Also, the stock servos were not fast enough.  Finally, the processor was too slow – we needed something with more horsepower.  Most other entries were using Lego robots – they didn’t do well either.
  3. Most of the kids were not part of a team, and did not appear to have a coach.  Unfortunately, their designs often failed to make the first turn.  For the Elementary School age group, good coaching is critical.
  4. Our robot was designed to be aggressive – there was no logic to backup and retry if it was confused, it was always moving forward.  Exception processing logic was not something these girls were ready for, so the more complex maze design now used by the competition would be a challenge for this age group.

Video

Pictures

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