From: Watson 'Atto Parsec' Name
Subject: Re: Another Proximity Detector and I need Help!
X-Newsreader: MicroPlanet Gravity v2.60
Date: Sun, 15 Dec 2002 09:48:32 -0800
NNTP-Posting-Date: Sun, 15 Dec 2002 11:00:10 PST
Organization: InReach Internet
In article ,
> Hi All, In playing around this morning, I designed another Proximity
> detector and it works great. Quite sensitive and stable!
> Unfortunately after doing some oscilloscope measurements and other
> tests on it, it doesn't work in the Principal I expected it to.
> Actually, I can't figure out how it does work, but it does!
> I am not looking for Guesses here, but can someone build it and give
> me a real answer. I'm Stumped!
> Its "Proximity-2" in my Projects area!
> If you can figure it out, Please E-mail me.
First off, the 4011 is a quad NAND gate, not AND gate as you have it
shown. So with two consecutive gates, you have 360 degree of signal
inversion, so it's in phase, and should oscillate. And the caps and
detector plate stuff damp out the oscillation when someone comes near.
The sensitivity pot is only 500 ohms, which looks too low. And _again_
you have the LED drawn the wrong way. Oh, well. Remember the cathode
goes to negative.
> Thanks in Advance and Take care.....Gary
My email address is whitelisted. *All* email sent to it
goes directly to the trash unless you put NOSPAM in the
Subject: line. alondra101 hotmail.com
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Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html