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ask for help

stevenyuenstevenyuen Posts: 3
edited 2010-02-05 03:01 in Robotics
since my school ask me to build a robot which can use the robot to detect a ball and then pick up·the ball( which may have three different calour( red , blue and green) and then sort the···ball.........so i would like to use ping sensor to detect for the distance ball and then go to along with the ball.......can anyone help me to solve this problem...i dont know how to program and use the ping ........can anyone help me................!!!
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Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2010-02-02 04:51
    Start with "What's a Microcontroller?" and the "BASIC Stamp Syntax and Reference Manual" to learn programming and "Robotics with the BoeBot" for programming examples and concepts for robotics. There are plenty of examples of Stamp programming for the PING))). Like most Parallax products, there are links to documentation and sample code on the webstore page for the product.

    www.parallax.com/tabid/440/Default.aspx
    www.parallax.com/tabid/535/Default.aspx
    www.parallax.com/Store/Sensors/ObjectDetection/tabid/176/CategoryID/51/List/0/Level/a/ProductID/92/Default.aspx?SortField=ProductName%2cProductName

    Look at the CMUcam which can locate colored balls and control a servo to track the ball

    www.parallax.com/StoreSearchResults/tabid/768/txtSearch/cmucam/List/0/SortField/4/ProductID/29/Default.aspx
  • stevenyuenstevenyuen Posts: 3
    edited 2010-02-03 04:18
    i want to ask, does it possible to make my robot to track the ball with a range of around 50cm?? urgently..............since my experiment table is about 1.1meters
  • Mike GreenMike Green Posts: 23,101
    edited 2010-02-03 04:41
    It's impossible to answer your question without a lot more information. For example:

    1) What are you using to track the ball?

    2) How big is the ball?

    3) What material is the ball made from?

    4) How fast can the ball move?

    The PING))) has a maximum range of 3 meters, but that doesn't mean it can detect a small object at that range. It doesn't mean it can detect a large object at that range if the object is rounded and made of a material that poorly reflects sound waves at frequencies around 40KHz.
  • stevenyuenstevenyuen Posts: 3
    edited 2010-02-04 05:37
    1.) Ping,)))
    2.) about 5cm in diameter
    3.) plastic
    4.) the ball dont need to move.....it is at some fixed position inside a square which is 1.5m X1.5m
  • Mike GreenMike Green Posts: 23,101
    edited 2010-02-04 06:12
    This might be able to work if the balls are on wire stands so they're up off the floor a couple of diameters, otherwise the PING won't be able to distinguish between reflections from the ball vs. from the floor a little closer to the PING. No guarantees though. You'll have to do some experimenting to make sure it would work.
  • P!-RoP!-Ro Posts: 1,189
    edited 2010-02-05 03:01
    It probably just depends on the angle. If the ping is at an angle barely pointing to the floor it should be fine, but if it's pointing down at 45 degrees or more it may start picking up the floor. You could probably still tell the difference though with angle vs. length of signal produced, but that will take a little more programming to do.

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    PG
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