From: clarke@next1.cs.ucf.edu (Thomas Clarke)
Subject: Re: Cheap Head Orientation Sensors
Date: Tue, 3 Dec 1991 14:27:15 GMT
Organization: University of Central Florida



In article <1991Nov27.023314.25648@watserv1.waterloo.edu>  
dstamp@watserv1.waterloo.edu (Dave Stampe-Psy+Eng) writes:

> clarke@next1.cs.ucf.edu (Thomas Clarke) writes:
> 
> >Horizontal is easy using the electronic automotive compass available 
> >from Radio Shack (don't have part number to hand, but cost is about $50).
>
> - Magnetic field varies greatly with position near any metallic object.
> You probably couldn't use it indoors or near monitors (LOTS of noise!)

The problem isn't all that bad.  A group here, working with magnetic Polhemus
sensors, also has to be careful of working near file cabinets and the like.

> Oscillation after changes in head angle.  This could be greater in
>amplitude than the head movement, and last for 1-2 seconds.

The electronic levels read out in degrees.  We hope the oscillation is not
a problem or we well have some sick subjects.