At 07:16 PM 11/11/97 -0500, Sean Breheny wrote:
>I have
>two questions, what type of maximum range do you want this to handle and
>what will be the accoustics of the areas where you envision it being used?
>This is tough to implement >10meters range when indoors because stray
>reflections are detected.

Sorry I forgot to actually anser your questions in my first reply... :-)

As I initially envisioned this, it was a tool for model robotics.  As such, I
 imagined ranges of a few inches to about 10 feet maximum, and primarily indoor
 usage.  Some PICLISTers have suggested other uses, such as measuring stock in
 grain silos or water or oil tanks.  In those cases, it would be ranges from
 several feet to several dozen yards.

By placing the transducers inside of pipes or cylinders lined with some
 sound-absorbing substance (like velvet or some other cloth) we should be able
 to get good directivity, and with different resistor values in the op-amp
 circuits, we should be able to tweak the gain to accomodate the longer
 distances.  I have been planning on 8 bits of granularity in the measurements,
 scaled over whatever time period is appropriate.  For robotics work, the scale
 would obviously be smaller than for the grain silo application....

Because PICs are so easy to reprogram, it makes sense to have several "standard"
 Ranging Unit programs available which scale the 256 possible output values over
 various distances.  End users could simply pick whatever range was most
 appropriate for their application.

What do you think?

 - Rick
---
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