Is this possible?

Discussion in 'The Projects Forum' started by johncena, Feb 12, 2012.

  1. johncena

    Thread Starter Member

    Aug 15, 2010
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    A microcontroller based sensor that can measure a given board (ex wood, cardboard, pcb) 2d only

    ex. when you placed a PCB inside it, it will measure the PCB's current size (or area) and then show it to the user via Graphics LCD
     
    Last edited: Feb 13, 2012
  2. MrChips

    Moderator

    Oct 2, 2009
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    Not very likely.
     
  3. praondevou

    AAC Fanatic!

    Jul 9, 2011
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    Is this something you saw, or something you want to build?
    What would be the maximum dimensions to be measured? What the precision?

    Do you want to buy a sensor off-the-shelf?

    I'm sure you didn't think about something as sophisticated as this laser scanner,right?:D
    http://www.creaform3d.com/en/handyscan3d/handyscan3d-video.aspx
     
  4. johncena

    Thread Starter Member

    Aug 15, 2010
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    something i want to build, the max will be 12 by 12 inches only, precision is a must actually.. although it is good to detect only the copper side of the PCB, not the plastic/non conducting side of the PCB.
     
  5. johncena

    Thread Starter Member

    Aug 15, 2010
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    that's too sophisticated :D,

    the scanner that i want to build only measures 2d, just like the common scanner for computers, but it will only detects/measure the copper of the board then displays it using Graphical LCD
     
  6. luvv

    Member

    May 26, 2011
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    I's not as cool as lasers but you could use a box w/ raised contacts.

    One positive contact in the center of the grid, then its just a matter of calculating the resistance for a given board size.

    Or the number of contacts conducting..w/e

    OR a grid of phototransistors/resistors on the bottom and bright light over head..

    Think it just comes down to the ability to map a grid w/ a pic, of which i know jack squat...but im sure it's doable.

    Interesting project tho i would like to see what you come up w/.
     
  7. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    How will this be any faster than just measuring it with a micrometer/caliper?
    What "precision" do you require?
     
  8. johncena

    Thread Starter Member

    Aug 15, 2010
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    we would like to measure also the surface area of irregularly shaped PCBs, then the microcontroller will output the image/coordinates/measured size to Graphics LCD
     
  9. johncena

    Thread Starter Member

    Aug 15, 2010
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    since PCB is made up of Copper (plain PCB, not etched), i would like to run a current on it then use a current sensor or something like that, that will scan the board on a gantry.
     
  10. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    Not sure where you are going with the current sensor..

    Again..What precision do you require?
    Whats the real end use? Who just gets small random un-etched copper clad in irregular shapes that they need to accurately determine surface area..
    Maybe you could do it by weight instead
     
    Last edited: Feb 14, 2012
  11. williamj

    Active Member

    Sep 3, 2009
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    I just read an "Instructable" were someone hacked a digital caliper and added a larger external readout. Is that what you're talking about?

    williamj
     
  12. williamj

    Active Member

    Sep 3, 2009
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    Ooops, should have added... You could use two and then use a pic or something to compute and display the output.

    williamj
     
  13. luvv

    Member

    May 26, 2011
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    Think what he is talking about is the point to point resistance of the copper.

    That i think would be very hard to do considering the very small resistance differences you would be dealing w/.

    That along w/ variables like thickness of the clad,purity of it etc etc.

    What i was talking about was the resistance of a many matched resistors in a grid.
    The more resistors in contact the higher/lower the resistance.

    These methods would only give a estimation of area not dimensions.

    Another idea i came up w/ is along the same lines in it will only give area but would be much more reliable and cheap and easy.

    Solar panel, light above the box sets the base voltage any object placed on the panel would decrease the output of the panel and you could work out a formula to establish area.

    If you want dimensions, you are going to need lines.

    Lines of conductors of some sort be it simple copper contacts or photo transistors, photo diodes in a grid array.

    Then the pic would only need to read a high or low state on it's I/O ports

    I really like this project, tempted to build something just for giggles:D

    Please don't abandon this thread till you decide on something i wanna see where it goes :(
     
  14. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    The answer is highly dependent on the precision/accuracy required.
    Chances are a 2d laser/profile scanner/ccd imaging camera would work..
    Or 3d digitizer arm (or gantry mounted probe)
    Or even something like whiskers/microswitches that you move the object over and calculate size based on movement speed/switch displacement.

    But
    Precision ain't cheap and cheap ain't precision.
    or my favorite
    Better/Faster/Cheaper..pick 2
     
  15. johncena

    Thread Starter Member

    Aug 15, 2010
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    Another idea we came up with is to use a roller with multiple thin metal rings in it ...
    the idea is to tap a current in the pcb board, then the roller that is attached to a gantry will roll to the pcb (in y axis). Then basically, the current will move from the pcb to the metal rings . We will attach a small connection wires to all the metal rings then the microcontroller will interpret this my determining what wires have voltage, and draws it to the Graphic LCD. With this, the system can determine the copper part of the board and not the plastic/non-conductive part.

    Is this possible?
     
    Last edited: Feb 19, 2012
  16. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    AGAIN... What precision/accuracy do you require?
    And what exactly are you using this information for?
     
    Last edited: Feb 20, 2012
  17. johncena

    Thread Starter Member

    Aug 15, 2010
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    the precision would be 1~2mm. As i think you can't make two copper/trace lines out of it when applying it on simple circuits... (though i might be wrong)..

    Well i think it is a good idea to make a scanner that only detects the copper side of the PCB and then draws it to Graphics LCD, i have never seen one before though, and i think it would be great when used it for CNC pcb drilling machine without the use of PC.
     
  18. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    I have NO idea what they heck you are trying to do nor its purpose.
    I give up trying to guess..
     
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