Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!samsung!uunet!mcsun!ukc!inmos!cheetah!kevin
From: kevin@cheetah.inmos.co.uk (Kevin Cameron)
Newsgroups: sci.electronics
Subject: Re: Hall Effect Sensor (Magnetic Compass)
Message-ID: <16829@ganymede.inmos.co.uk>
Date: 24 Jun 91 11:57:16 GMT
Sender: news@inmos.co.uk
Followup-To: Hall Effect Sensor
Organization: INMOS Limited, Bristol, UK
Lines: 18

I always wanted to build a Hall-effect compass - but never got round to it.

The major problem seemed to be that the devices are quite temperature sensitive
and are therefore difficult to get absolute values from, however it does always
exhibit minimum resistance at minimum field strength. I would therefore suggest
that an accurate measurement of the Earth's magnetic field can be found by
placing the device inside a coil which can be magnetised to neutralise the
Earth's field, and the coil current will then be proportional to the Earth's
magnetic field. Two devices at right-angles can then give you a bearing.

Hope somebody finds this useful.

Apologies if this re-iterates anything in "Radio Electronics", which I havn't
read.

-------------------------------------------------------------------------------
Kevin Cameron         INMOS, 1000 Aztec West, Almondsbury, Bristol BS12 4SQ, UK
kevin@inmos.co.uk     Tel: (UK) 0454 616 616 x364, Fax: 617 910