🚀 go-pugleaf

In article <pwgxncm@rpi.edu> weisee@aix.rpi.edu (Elizabeth A. Weise) writes:
>In article <l53rt7INNhbk@news.bbn.com> koolish@BBN.COM (Richard M. Koolish) writes:
>>
>>Has anybody had any experience with any kind of machine readable compass?
>
>I found that Radio Shack was discontinuing their automotive compass, which
>uses fluxgate technology. Not worth $50 as a toy, but for the $30 or so
>closeout price, I found the last two in about 5 stores around me... one for
>a guy at work. Looks like it shouldn't take much more effort to make it
>interfacable, and I think I've heard about an article in Radio Electronics
>describing how to do that, though I haven't seen the article.
>
>-- tom moeller, under the guise of
>-- 
>****************************************************************************
>Beth Weise / PhD Student / Dept. of Language, Literature, & Communication
>Rensselaer Polytechnic Institute / Troy, New York
>Weisee@rpi.edu / Beth_Weise@mts.rpi.edu

Yes it is pretty straight forward.  Inside there is a dual op-amp (I don't
recall the part number) which is used to drive the coils to point the front
dial.  The two outputs are 90 degrees out of phase (find the heading by taking
the atan2(x,y) of the signals) and swing from about 2 to 6 volts, though the
levels change linearly with the calibration knobs on the side.  Your only
concern then, is reading the analog values into the computer.  I
normalized the x,y values so they each had a range of +-1, though I'm not
so sure why I did it now...

Good luck,
	Kevin
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Kevin B. Stanton			Internet: kevins@eecs.ee.pdx.edu
Portland State University		Dept. of Electrical Engineering
(503) 725-5422				Box 751, Portland, Oregon  97207