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From: jorice@maths.tcd.ie (Jonathan Rice)
Newsgroups: sci.virtual-worlds
Subject: Re: Polhemous tracking devices
Message-ID: <1990Sep21.143120.21614@maths.tcd.ie>
Date: 21 Sep 90 14:31:20 GMT
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In <7467@milton.u.washington.edu> zik@bruce.cs.monash.OZ.AU (Michael Saleeba) wr
ites:

>Does anyone know how polhemous (sp?) tracking devices work?
                      ^^^^^^^^^
                      Polhemus
Sorry, not really. I was told it was some sort of system using an AC
magnetic field.

>It seems to me that these devices are even
>more impressive than datagloves; apparently being able to sense location, 
>direction, and rotation in three dimensions.

Sure they can, but they can't measure finger positions (unless you put one on
each joint, which is overkill). A position and orientation sensor such as the
Polhemus is part of most gloves - VPL's Dataglove actually has a Polhemus
sensor mounted to the back of it, while Mattel's PowerGlove uses an ultrasound
ranging system.

>Also, does anyone know who produces these devices commercially and how much
>they cost?

I don't have any price for the Polhemus, but I don't think you're talking
cheap here. I do have some info on a full plug-in-and-go RS-232 position and
orientation device from Ascension Technology Corp. of Vermont that uses a
*DC* field. This apparently gives better immunity to eddy currents in metallic
objects in the sensor's vicinity. Anyway, that device costs $5000. Not cheap.

The beef:
        The Bird (TM) 6D graphics input device
        Ascension Technology Corp.
        P.O. Box 527, Burlington VT 05402
        Tel: 802-655-7879

There's also this similar device called the Flying Mouse (TM):
        Flying Mouse (TM)
        SimGraphics Engineering Corp.
        1137 Huntington Dr., Suite A-1,
        South Pasadena, CA 91030
        Tel: 213-255-0900
        Fax: 213-255-0987
I don't have a price for that. It uses a Polhemus sensor.

-- Jonathan

Jonathan Rice, jorice@cs.tcd.ie

Disclaimer: I've no connection with Ascension or SimGraphics. I've a slender
enough connection with anything in the real world, come to think of it.