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Improving the playing field

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  • Improving the playing field

    My team has asked that I post something to this forum in hopes of improving the playing field.

    For Ringmaster the team started using the line follower. They tried the "edge" follower example in RobotC but didn't like the jerky motion . Instead they used the example code and physical setup from EDR, I.e. used three IQ color sensors. Unfortunately the white dots present in all the black lines caused issues especially when attempting to line follow, gyro turn, then line follow again. The problem occurs if all three sensors saw white after the turn it didn't work . To see if it was their set up they used black electrical tape to cover up the white "holes" and the problem went away.

    Would it be possible to create a package for sale of black tabs so the black lines would be all black avoiding this issue?

    p.s. The team knows this might be a huge logistical nightmare given the number of fields out there. But they still wanted me to ask.

  • #2
    Could the black version of these work?

    https://www.vexrobotics.com/vexiq/pr...thinsheet.html

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    • #3
      If the height of those pins created a flush surface, that would be perfect. Nice find.

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      • #4
        I don't think that changing the playing field like this would happen anytime soon. My kids have found better success by having the h drive do the line following.

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        • #5
          sankeyd, What is the "h drive" you refer to?

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          • #6
            The perpendicular omni wheel that allows strafing. If you see Black, set it to 5, if you see white, set it to -5. You still swim a little bit, but you are at least facing the right direction.

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            • #7
              Originally posted by mmarquis View Post
              sankeyd, What is the "h drive" you refer to?
              "H drive" refers to a chassis design that uses 5 omni wheels. 4 are oriented like the normal wheels on a robot (vertical lines in the "H") and a 5th is the horizontal line, which can drive the robot sideways.

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              • #8
                Either way, to improve line following, you need to make the sensor less "sharp".
                If you place the sensor really low, youl'll see bright whites and deep blacks. And every hole and sharpie mark on the field too (our school has a label on every tile). Your signal from crossing a line would be like ___|---|___
                If you place the sensor high enough, much bigger area of the field will get averaged. A hole would still influence the readout, but not as much and you can set up a better threshold. Even the edge following with a single sensor would become feasible, since you can form a proportional control. Your signal will be more like ___,/^\.___.
                Now, if you place it too high, your signal-to-noise ratio would diminish. I think my students used to place the sensor about 3/4" - 1" high, but at worlds this year, I have also noticed a line follower with the color sensor mounted at 45deg angle instead of flat.
                There is one more issue with sensor too high, uneven lighting conditions at tournaments. So you either need to implement some form of threshold calibration, or make sure to block external light from entering the sensing area.

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