From: jn@tommy.demon.co.uk (John Nissen)
Subject: Re: TECH: Cheapest or more efficient Head Tracking Tecnology
Date: Thu, 16 Jan 97 09:17:39 GMT
Message-ID: <853406259snz@tommy.demon.co.uk>
Organization: Myorganisation


In article <32D622EF.167E@robot.uvsq.fr>
           chamot@robot.uvsq.fr "resp J.Guy Fontaine" writes:

> .. my job is to find (for the lowest price) how to built an
> efficient head tracker. I know some of the technologies used (as
> magnetic by Ascension and Polhemus for example), but I'm asking why
> the Ultasonic way isn't very used?

Various devices have been developed for disabled people who need a
pointing device and can't use a mouse.   Some use a magnetic effect
(the Hall effect I think) and it is possible to detect tiny
movement in the Earth's magnetic field through induced current.
Others use light, typically infrared. (One uses a camera to 
track the position of a reflective spot you put on your forehead.)
Another possibility is to use solid-state gyros - see Electronics 
October 1996.  I've not seen ultrasonics used.  I would be very
interested in a cheap solution for head tracking, or even better,
for eye movement tracking.  Please contact me on jn@tommy.demon.co.uk

Cheers from Chiswick,

John
-- 
Access the word, access the world    Tel/fax +44 181 742 3170/8715
John Nissen, Chiswick, London, UK    Email to jn@tommy.demon.co.uk