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From: gurney@kira.msu.edu (Eddy J. Gurney)
Newsgroups: sci.electronics
Subject: Dec 90 Radio-Elec "Christmas Card" article
Summary: Another similar circuit?
Message-ID: <1990Nov2.142454.10784@msuinfo.cl.msu.edu>
Date: 2 Nov 90 14:24:54 GMT
Sender: news@msuinfo.cl.msu.edu
Organization: Department of Computer Engineering, Michigan State University
Lines: 34

I just got done reading the latest issue of Radio-Electronics.  Or at
least part of it. :-)  There's an article in the December issue on building
a "Christmas card" that has 50 LEDs that blink in response to an AGC'd
microphone audio input.  The article explains that they're really just
"bar drivers", driven in either dor or bad mode, depending on the singal
level.

Great.  Sounds like it could be interesting.  BUT...

I'm sure everyone has seen those "Light In Motion" 140-light sets that
appear to "move" by blinking the four different color lights in sequence.
I have such a string, and after reading the article, had this great
idea:  How hard would it be to use a similar audio filter and instead of
lighting a bunch of LEDs, turn on one of the four groups of lights on
the string?  e.g., low frequencies would turn on the blue lights, lower-mid
frequencies the blue ones, upper-mid the red, and high frequencies the
yellow ones.  I think it would be a pretty neat effect to have a set of
lights on the tree (or wherever) that "blinked" to the "ambient" Christmas
music, or Christmas carols, or whatever!

I don't have R-E going back to when Don Lancaster had his "organ lights"
(or whatever he called it back then) which was similar to what I want 
to do - except I think that OLD article is probably a little out of date
for the times anyway... 8-)

Any suggestions on this?  Somebody wanna whip up a circuit for me?  (I'm
still working on my BS... ;-)

aTdHvAaNnKcSe,
E.J.G.
--
      Eddy J. Gurney, N8FPW           THE ECCENTRICITY GROUP
eddy@jafus.mi.org -- gurney@frith.egr.msu.edu -- 17158EJG@MSU.BITNET
(Preferred)          (But this is OK too)     (Only if you have to :-)