Newsgroups: comp.robotics
Path: brunix!sgiblab!swrinde!cs.utexas.edu!uunet!amiserv!gsievers
From: gsievers@cyclone.xnet.com (George C. Sievers)
Subject: Re: Ultrasonic range sensor - formfactor of prox. switch
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Organization: Real Time Integration, Inc., Chesterton, IN
References: <94047.115059AXB30@psuvm.psu.edu> <761426374snz@cryton.demon.co.uk>
Date: Sun, 20 Feb 1994 12:58:00 GMT
Expires: Sun, 20 Mar 1994 06:00:00 GMT

In article <761426374snz@cryton.demon.co.uk>, Patrick Arnold wrote:
> In article <94047.115059AXB30@psuvm.psu.edu> AXB30@psuvm.psu.edu writes:
> 
>> (stuff deleted)
>
> Farnell Electronics in the UK sell an ultrasonic proximity sensor switch, made
> by Honeywell, that has a range of 130-500mm, adjustable by a pot. The output
> frequency is 215kHz, which should make it quite directional. It costs 116.96
> UK pounds.
> 
> Patrick.
> 

Is there some formula which describes the directionality of an ultrasonic
beam as a function of frequency?  There are MHz ultrasonics available and
I'm interested in researching the 'tightness' of the beam over a distance
of 2-3 meters.

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George C. Sievers                         Real Time Integration, Inc.
Programmer/Analyst                        1200 Broadway, Suite 3
Email: gsievers@cyclone.xnet.com          Chesterton, Indiana, 46304
Voice: (219) 929-1936                     FAX: (219) 929-1518 
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