From: Dave Stampe-Psy+Eng <[email-masked]>
Date: Wed, 16 Oct 91 20:48:34 -0400

K. C. Lee  ([email-masked]) replies:

>I suspect the sampling rates of the glove can go much faster if the
>glove CPU don't have to process the 6 sets of distances into (X,Y,Z,Rotation).
>In that case the only limitation would be how fast can the receivers settle
> so that the transmitter can send another ping.

I don't believe the CPU is doing any special processing.  I did some work on 
an implementation using an 80C196, and the math required a lot of 32-bit
multiplications, divisions and roots, about 4 mS worth on that processor and
out of the question for an 8-bit processor in any reasonable time.
 
Also, if you compute the distortion that would be caused by just using 
the difference in delay between horizontal and vertical receiver pair
response times, you get a response very like the one I've measured: about
50% better resolution at 100 cm distance as compared to 200 cm.

I've also scoped the unit in operation and there isn't any extra time for
calculations.  The CPU waits for incoming pulses for 20 mS times 2 trans-
mitters, for a total of 40 mS.  This corresponds to the 25 Hz read rate
seen if the finger timing circuit is defeated.  BTW, 20 mS corresponds to
a maximum echo path of 6.8 m (22'), which seems reasonable to me.  Any 
less, and you could only use it in a padded cell! (B-{)

Of course, the processor COULD attempt to do the math while it's waiting
for the receivers to respond, but I don't think it is.

-Dave Stampe