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Scribbler Line Following Troubles — Parallax Forums

Scribbler Line Following Troubles

DoctorDementoDoctorDemento Posts: 3
edited 2007-06-13 20:03 in Robotics
My instructor purchased two Scribbler 'bots for use in our programmable controls class. We are having problems with them following lines. We have tried using the printouts from the CD from both inkjet and laserjet printers, and black electrical tape, nothing works. You enter either the test or line follow mode and pass the Scibbler over the lines and the LED's do not indicate that it is sensing. I have also tried the program in the BS2 hackers folder and monitored the sensor in the debug window. Anybody else having trouble. Just watched the line follow video and I wish ours would react like that.

Comments

  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2007-06-13 15:27
    Hello,

    The line sensors are calibrated to a specific height so it is important that the line be flat on a smooth surface and there be no modifications to the wheels which might affect their height. The line needs to be made of a material that does not reflect IR light. We have found instances of printers (mainly photo printers with metallic ink) which have a reflectivity almost as high as white paper. If you go to the observation deck within the GUI can you see the sensors working properly when you move the scribbler over a line? When sitting on the line/paper what do the sensors report in the observation deck?

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    Chris Savage
    Parallax Tech Support
  • WhitWhit Posts: 4,191
    edited 2007-06-13 16:03
    Doc,

    I tried mine on some low carpet (even though it says not too!·nono.gif·) one day and it did not work well. A smooth flat surface is important. Also it helps to have paper that is thick enoungh if you are over a dark surface (high contrast between the line and paper). Chris' idea about using the observation deck to check out what you sensors "see" is great.

    If you are on a slick surface, you may want to tape you sheets together to the floor otherwise your scribbler will slide them around.

    Good luck!

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    Whit+


    "We keep moving forward, opening new doors, and doing new things, because we're curious and curiosity keeps leading us down new paths." - Walt Disney
  • DoctorDementoDoctorDemento Posts: 3
    edited 2007-06-13 17:11
    Where is the 'Observation Deck' located on the GUI?
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2007-06-13 17:41
    To access the Observation Deck, you need to download the latest version of the GUI. This feature is not included with the CDROM version. Then, go to the help screen (Getting Started -> Monitoring Sensors) for instructions on how to use the Observation Deck.

    -Phil
  • DoctorDementoDoctorDemento Posts: 3
    edited 2007-06-13 18:42
    Thank you for the replies. I will download the latest version but just to let everyone know I have finally succeeded! The IR line following sensors are EXTREMELY sensitive to the quality of black. The deskjets I tried were to gray. The first three laserjets I tried were either to shiny or low on toner. I finally found one that would print dull lines, cleanly and the Scribbler is now working normally. yeah.gif
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2007-06-13 19:16
    If you ever decide to try the tape route again, McMaster-Carr sells colored masking tape (p/n 76265A41-black) which I've had good luck with. It's much less glossy than electrical tape.

    -Phil
  • WhitWhit Posts: 4,191
    edited 2007-06-13 20:03
    DoctorDemento said...
    ·I will download the latest version but just to let everyone know I have finally succeeded!· yeah.gif
    Great!

    Phil, Thanks for the tip on the black masking tape!


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    Whit+


    "We keep moving forward, opening new doors, and doing new things, because we're curious and curiosity keeps leading us down new paths." - Walt Disney
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