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From: nagle@netcom.com (John Nagle)
Subject: Re: Optic short distance range finder
Message-ID: <nagleCzHoz7.3uK@netcom.com>
Organization: NETCOM On-line Communication Services (408 261-4700 guest)
References: <39dood$ccp@handler.Eng.Sun.COM> <3aj40o$pvb@nntp.Stanford.EDU>
Date: Sat, 19 Nov 1994 00:49:55 GMT
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Manish Sharma <manish@leland.stanford.edu> writes:
>We are designing a Micromouse here for the Micromouse Competition. We
>were deciding 
>about what kind of distance sensors we should use when we saw your
>article. 

>We need to use 

>   1. sensors for measuring forward distance (in the range of 0-3m), 
>   2. sensorts for keeping the mouse centered in the maze (width 18cm,
>mouse body 
>        should probably occupy 0.5 of it).

      A standard trick for very short distance measure is relative
intensity measurement.  You have two emitters/detector pairs, arranged
so that one is further back than the other.  From the relative intensity
measured, distance can be sensed independent of the target reflectance.
This technique is sometimes used in robot hands; the Stanford "blue hand"
was, I think, the first to use it.

      You use this for very short distances, not meters.  It's a
replacement for whiskers, not vision.

					John Nagle
