Subject: logitech

From: Dave Stampe-Psy+Eng <dstamp@watserv1>
Date: Thu, 13 Aug 92 20:36:53 -0400

Well, I just tried out the Logitech 6D mouse/ head tracker prototype.
Seems to work OK and best of all, YOU CAN USE IT WITH THE POWERGLOVE.
Almost no interaction.  You can also buy 2 Logitech systems and cascade
them (one as a mouse, the other as head tracker.  The unit has 25 
samples/sec with 2 meters range, 0.5 mm and 0.5 degree accuray as a head tracker and 67 cm range, 0.25 mm and 0.1 degree accuracy as amouse at 50 samples/
sec.  Not much glitching either.  

It seems to use comparative phase between receivers to get the angle
(since if you rotate more than +/- 70 degrees it gives false angles 
until you center it again).  The transmitter is a 25x20 cm triangle,
and the head tracker is a 6x8 cm triangle.  The cable on the head tracker
is a bit short, though (hopefully extensins will be available.

I would suggest one of 2 ways to use the head tracker: put it on front of 
the HMD and accept limited head rotation, or put the transmitter on the
ceiling, and the triange on top of the HMD.  This will give a position range 
limited by the ceiling height, but lets you turn around completely.

Impressions: Hard to tell from the prototype, but it looks good.  Low
glitching, light weight etc.  Only problem, this thing is NOISY!  The
transmitter elements were custom designed for high risetime pulses, and
the amount of 10-20 KHz this thing gives out will definitely keep insects
away (it gives me a headache at close range).  Anyway, this thing looks 
like a pretty useful head tracker, but the mouse will still tie you down.

So: should REND386 support this?  I understand PCVR is going to do something
on it next issue, but it might be worth building it in as the default 
head tracker and secondary manipulator.  Comments?  Should we be looking
at drivers installable later?

- Dave Stampe