OT:Distance to CV

[Paul Perry]

At 09:26 PM 10/03/00 US/Eastern, you wrote:
>Hi all,
>
>I am working on making a controller that senses 
>proximity.  Like a theremin, but with two major 
>diferences: 1. that it has far reach (maybe up 
>to 8 meters),

Only ultrasonics will do this.
A theremin appraoch certainly won't.

For maximum reliability, you need a transponder,
at the point you want to know the distance from.
So a toneburst (ultrasonic) goes from the base station to the 
transponder, which then sends a signal back.
A clock counting the time involed from send to receive then 
outputs to a D to A convertor.

The model robot kids do this stuff all the time.
Maybe one of those 'car parking radar' kits could be hacked.
Also, Polaroid used to sell an ultrasonic distance measurer based
on their rangefinder.

paul perry Melbourne Australia