Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!ncar!asuvax!hrc!xroads!wiz
From: wiz@xroads.UUCP (Mike Carter)
Newsgroups: sci.electronics
Subject: Re: Need Electronic Pest Control Circuit
Summary: Hold on one minute here...
Keywords: Scam
Message-ID: <760@xroads.UUCP>
Date: 12 Jul 89 10:54:56 GMT
References: <12630@well.UUCP> <23011@quacky.mips.COM>
Distribution: sci
Organization: Crossroads, Phoenix, Az
Lines: 71

> In article <12630@well.UUCP> fgk@well.UUCP (Frank G Kienast) writes:
> >
> > 
> "Ultrasonic Pest Control" does not work, notwithstanding the fact there are
> manufacturers getting rich selling these fraudulent devices. As I understand
> it, U.S. Army tests showed that such machines have little effect on mammals
> such as mice and dogs, and no effect on mosquitoes and other insects. No I
> can't quote a source.


We should take a moment here to consider what the Ultrasonic "Pest"
controllers were originally designed to do.
From the information that I have they were originally made to repell such
nasties like Cockroaches, Crickets, beetles and their genre'.
The scientific application notes include some rather amusing data which I'll
throw in here a little further.
The frequencies involved here are pretty wide for each of the above listed
pests. Most units (the cheepies) transmit a single frequency (usually around
22KHZ) and have little effect. The better units (my kit built job) oscillate
up and down from 21KHZ up to 28KHZ. At these frequencies the membranes and
scilia on a lot of these creatures will oscillate in kind if the unit is
powerfull enough. To test this, I captured about a dozen crickets an put them
in my converted fish tank - specimen observatory a few years back..gave them
water and lots of dog food ( a treat they adore ) and the ventillation
provided by the overhead screen & fan. ...one nasty treatsie included was
this "Repeller". I went to work and came back about 10 hours later to find
all but two of them stone dead under a rock.
 
I ran this unit for about 2 weeks..until my wife mentioned that both Wolves
and the two cats stayed clear of the kitchen where I had it operating.
The cats refused to enter the kitchen (where their bowls were) and she
resorted to feeding them in the family room. The wolves were'nt immediately
affected but the best shaded spot nearest the window was always vacant.
I imagine it became more of an irratant to them than anything else.
 
I'd like to read the U.S. Army's refutation..if it is indeed that..more than
likely (I'ma reservist) they were testing them to determine usesage in
camp environments in the field or some twisted anti-personnel device.
 
A side issue in this journal was included in the discussion of ultrasonic
laborratory tests. It involved the testing against cockroaches 
[mentioning that different species required different frequencies due to size
and make-up] and that a blunder brought about an interesting result in
some electronic measuring scales used at meat markets....apparently the
clowns who designed this one type of scale were getting complaints
from owners who said the scales would cease to operate after about 3-4 months
of use. The units were sent back into the factory for repair..where..
much to the dismay of the technicians upon removal of the pressure plate,
thousands upon thousands of dead cockroaches could be found.
The dead mass of *** YUCK *** interfered with the crossed taught wires
(Strain guage) -thereby producing erroneous measurements.
 
WHY ? Well, after a little research they discovered someone who affirmed
that the resonance or vibrations on these wires caused by (lots of
verbage) produced a 14KHZ sound wave. This just so happens to be the
mating frequency of la cucharacha..the despised cockroach.
 
 
I tested this out..being the sinister, scheeming, practical joker that I am
at times...by making a piezio transducer that operated near 14KHZ.
Filled the project box full of holes, two series-aiding 9-V batteries 
and a makeshift disguise later and whala-- THE COCKROACH GRENADE is born.
 
Not nice.
 
Enjoy
-- 
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= Mike Carter  N7GYX, Phoenix AZ| Q: Why did the Chicken cross the road  ?  =
= hplabs!hp-sdd!crash!xroads!wiz| A: To ESCape the Main Menu .              =
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