Newsgroups: comp.robotics
Path: brunix!news.Brown.EDU!agate!howland.reston.ans.net!pipex!uknet!bcc.ac.uk!news
From: donnett@anat.ucl.ac.uk (Jim Donnett)
Subject: Radio Shack Fluxgate Compass
Sender: news@ucl.ac.uk (Usenet News System)
Message-ID: <1994Feb3.093126.64812@ucl.ac.uk>
Date: Thu, 3 Feb 1994 09:31:26 GMT
Reply-To: donnett@anat.ucl.ac.uk
Organization: Anatomy Department, University College London, UK
Keywords: fluxgate compass
Lines: 30


(Reposting because this didn't seem to go out last time -- sorry if
 it actually did.)

I seem to remember a posting some time ago (perhaps even years ago)
describing how to use a Radio Shack fluxgate compass as a direction
indicator for a mobile robot.  If memory serves, it was possible to
take two voltages that drive the compass' built-in heading display,
and digitize them; these voltages represent the sine and cosine of
the heading, so taking the four-quadrant arctan of them would give
you the heading between 0 and 360 degrees.

My question is, at what points should these two voltages be measured?
I've managed to get it to work after a fashion by connecting to two
likely-looking resistors on the display circuit board, but the
performance/stability is a bit lacking (or am I expecting too much?).

Any information very much appreciated.

Jim 

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e-mail:  donnett@anatomy.ucl.ac.uk







