Subject:
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Re: Using sonar to approximate RADAR?
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Tue, 3 Nov 1998 15:55:29 GMT
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Original-From:
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Will <willbain@*StopSpam*cs.umt.edu>
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Reply-To:
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nepenthe@/NoMoreSpam/montana.com
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Viewed:
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1959 times
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Richard A. Cini, Jr. wrote:
<snip>
> I have a model police car, 1:12 scale R/C. I thought that it would be
> neat to have the car "patrol" an area containing other R/C cars, and
> determine which ones were "speeding". Obviously K-55 doesn't make a radar
> gun 1:12 size, so I gave it some thought. Why not use sonar; a Polaroid-type
> module, but smaller?
>
> I figure that the speed of the car can be derived from the distance from
> the police car to the perp as measured by two consecutive samples at a known
> time interval. Some quick math should give me ds/dt, distance over time.
> Exceeding a pre-set limit would trigger the autonomous searching.
That ought to work fine, provided the cop is almost directly in front of
or behind the "perp"; then no correction for angle is necessary. The
Polaroid sonar detects objects within about a 10-degree cone.
It might still work if the sonar is angled across the "roadway", but it
would take some careful calibration: You could estimate the relative
bearing of the perp vehicle based on the amount of time for it to cross
into and then out of the 10-degree cone (you'd need to keep sampling at
a high rate). That, along with a couple of range readings and a bunch
of trigonometry, ought to give you both the speed and the direction of
travel. Good luck!
--Will
, ,
__@_/ \_@__ |/
| /__, o @_/
)\ ) ( \ (\/\\,
~~~~~~~~~ ' ` ~~~~~~~~~~~ ` ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Wendy Parson, America is the only nation in history
Will Bain, which miraculously has gone directly from
& Tatoosh barbarism to degeneration without the usual
interval of civilization. --George Clemenceau
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Message is in Reply To:
 | | Using sonar to approximate RADAR?
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| Hello, all: <DELURK> I've been following this list for some time now, but since I didn't have an HB, I didn't contribute to the discussion. Now, I've just ordered my HB because I plan to start building. But I have a question... I have a model police (...) (26 years ago, 3-Nov-98, to lugnet.robotics.handyboard)
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