How do you know that the CCD is seeing a laser dot and not some other bright
dot of light?
Isn't a CCD kinda expensive?
Can you modulate the Lasers and use a photo diode with a filter with Q at
modulation frequency directed by a mirror on a pager motor? the filter
output pluses only when it sees the correct frequency and the time between
the two pluses is proportional to the distance.

James Newton, webmaster http://get.to/techref
(hint: you can add your own private info to the techref)
mailto:jamesnewton@geocities.com
1-619-652-0593 phoneÊ



-----Original Message-----
From: pic microcontroller discussion list
[mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Andy Kunz
Sent: Wednesday, August 25, 1999 2:21 PM
To: PICLIST@MITVMA.MIT.EDU
Subject: Re: Signal filtering through code


>Sounds almost perfect to what I need, except for one thing. They state,
>"As the microwave radiation penetrates many materials, such as plastics
>and ceramics which are opaque to light, the sensor modules can for many

Have you considered optical (laser) ranging?

Two laser transmitters set to converge at a spot at the far end of your
expected range.

Use a CCD to accurately measure the distance between the dots.  This is
linearly proportional to the distance.

Simple geometry --> simple code.

Andy

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Andy Kunz               Life is what we do to prepare for Eternity
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andy@rc-hydros.com      http://www.rc-hydros.com     - Race Boats
andy@montanadesign.com  http://www.montanadesign.com - Electronics
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