Checkers Project

Discussion in 'The Projects Forum' started by GingerDan92, Nov 26, 2013.

  1. GingerDan92

    Thread Starter New Member

    Nov 26, 2013
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    Im currently undertaking a project at university in which we are making a robot to play checkers and we have come across an issue, we have no idea how to read in where the pieces are in the board, my current thought is to have an LDR under each square and then using a parallel to serial converter to read it in. The issue is i have no idea where or how to make one of these.

    If anyone know a cheap alternative that would be great, please note we are on a restricted budget.

    Thanks again
     
  2. tracecom

    AAC Fanatic!

    Apr 16, 2010
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    LDRs should work, but alternatively you could use phototransistors. You could also use hall effect sensors with magnets in the checkers.

    How do you plan to differentiate between red and black checkers? Just rely on a memory scheme which always knows where the checker came from and therefore what color it is? With hall effect sensors, you might be able to use the polarity in the magnets to differentiate between red and black. Just a thought.

    RFID tags would be interesting as well.
     
  3. John P

    AAC Fanatic!

    Oct 14, 2008
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    I think the elegant way to do this would be to set up a TV camera pointed at the board, and detect the locations and colors of the pieces that way. With a known grid of 8x8 squares, establishing the 64 places to look for the pieces shouldn't be too hard, and it wouldn't take a full vision system to do it, just "some number of microseconds into the scan time of line X, check the light level".

    Actually if you use optical sensors peeping up through holes in the middle of each square, you could scan them with an 8x8 matrix, so it wouldn't need a huge amount of wiring. But I still think the TV camera is more fun.

    I can't see how RFID would do the job without setting up 64 RFID readers, for which most likely you would need custom-made pickup coils. That would be some serious money.
     
  4. tracecom

    AAC Fanatic!

    Apr 16, 2010
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    Although a checker board consists of 64 squares, only 32 of them are used in play (usually the black), so that simplifies any means of detection quite a bit. You may be right about RFID being prohibitively expensive; I have never priced the readers. Might it not be possible to have only one reader and use it to scan the 32 squares in question?

    The TV idea sounds like fun, but you might need to choose your board and checker colors to avoid having to see a black checker on a black square.
     
  5. wayneh

    Expert

    Sep 9, 2010
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    That's the first thing that popped into my mind. Polarity won't work for color unless the pieces are locked into "this side up".

    Detecting a jump might be challenging if the motion is sloppy.
     
  6. tracecom

    AAC Fanatic!

    Apr 16, 2010
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    If you used some of those 8mm neodymium button magnets, you could drill a hole in the bottom center of the checker and glue the magnets in. All the black checkers could have N pole out and all the red have S pole out. Then, just make sure that the magnets are down against the board for both colors.
     
  7. BobTPH

    Active Member

    Jun 5, 2013
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    This might also facillitate picking up the pieces with a robot arm, if that is what you intend to do. All you need an an electromagnet on the end of the arm.

    Bob
     
  8. tracecom

    AAC Fanatic!

    Apr 16, 2010
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    I am now thinking that you might need two hall effect sensors under each of the 32 active squares. One hall effect sensor would be face up and the other face down. That would be the surest way of knowing if there was a checker on the square and what color it was.
     
  9. THE_RB

    AAC Fanatic!

    Feb 11, 2008
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    A $20 webcam and freeware image recognition software on a PC is looking better and better... ;)
     
  10. tracecom

    AAC Fanatic!

    Apr 16, 2010
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    I did a little research; it seems that there is now a computer program (Chinook) that is absolutely unbeatable.
     
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