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Designing a coil polarity tester as a group project.

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  • Designing a coil polarity tester as a group project.

    Recently sock puppet came up with a little electronic circuit to help him determine humbucker coil polarities...
    http://music-electronics-forum.com/t41670/#post416896
    ... and I thought that this might be a good opportunity to come up with a project that can speed up and simplify this process as much as possible.
    Here's a list of the things I'd like this gismo to do:
    Show the polarities of two or even 4 coils at once.
    Have an integrated magnetic polarity tester to show north or south up.
    Polarities would be displayed via different colored LEDs, say red for north-up, blue for south up, green for clockwise, yellow for ccw.
    Have an integrated signal generator/inducer wand that pings each coil so we don't have to be clanking sharp chisels over valuable guitars.
    Getting to the super fancy functions:
    Perhaps a little 160 char display that could show a pictorial diagram of each coil with mag polarity and wind direction arrows.
    An on-board memory that would show us the wire color codes for all the pickup brands so we don't have to keep looking that shit up.

    I'm interested in other ideas and curious what the interest would be generally.
    Would you rather buy a finished product, build a complete kit or DIY the whole thing from a set of plans, a BOM and a PCB etch pdf?
    What would you consider spending on such a gadget; $20-40-60-80?

  • #2
    A pedal builder & friend of mine offered to get some of his guru's possibly involved layout done on stripboard & possibly done here . but I will wait to see what idea's we come up with first
    Guitar FX Layouts: Greeny's Vero Build Guide
    Guitar FX Layouts
    Where's Mr Hammer
    "UP here in the Canada we shoot things we don't understand"

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    • #3
      Humbucker versus Musicbucker

      One needs to sense both how the coils are connected and the orientation of the magnets.

      Here is an explanation of what's going on:

      http://music-electronics-forum.com/t23464/#post198264

      http://music-electronics-forum.com/t1837/#post12312

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      • #4
        I actually knocked up a little tester that did some of these tasks ...it was basically a hall transistor feeding a PIC....it was a doddle to get it do read gauss & polarity (though I never bothered with winding direction)

        With a hall transistor, if you apply 5V across two pins, with no magnetic field present the output pin sits at a quiescent 2.5V ....place it near a south magnet the output voltage increases linearly with gauss strength * vice versa....I simplay AtoD'ed this voltage then did some basic maths on the signal to give a gauss strength readout (& polarity) on my PC.

        it was really rough & ready (but then again I was in a rush)...it'd be a cool project for someone interested in pickups to run with.

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        • #5
          Originally posted by copperheadroads View Post
          Where's Mr Hammer
          He's in west end Ottawa here somewhere. ;-)
          Take Care,

          Jim. . .
          VA3DEF
          ____________________________________________________
          In the immortal words of Dr. Johnny Fever, “When everyone is out to get you, paranoid is just good thinking.”

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          • #6
            In the last 2 issues of Premier Guitar magazine the writer for the Mods section has a hands-on build of a Coil Polarity Tester. Parts list and step-by-step is given.

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            • #7
              I Don't see the purpose of the coil polarity tester that is in Premier Guitar magazine when an old analog meter will do the same test as is .
              "UP here in the Canada we shoot things we don't understand"

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              • #8
                True. I, personally, use an '80s analog meter to determine wind direction and a polarity tester for the magnets. This item Dirk built is another "toy" for techs to have on their shelves. And some "New" techs think analog is not suitable for anything. Their words, not mine.

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                • #9
                  A digital meter will do . As it either increases or decreases before displaying constant number with the same test . I was going for a 2 probe .Red light ,Green light tester ................The Analog meter has been around for What ? 40 years .... there is a reason I've stop subscribing to PG
                  "UP here in the Canada we shoot things we don't understand"

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