simple/cheap circuit for "dog chaser" or "ultrasonic

Paul.Secombe at CASRDH.HEALTH.nt.gov.au Paul.Secombe at CASRDH.HEALTH.nt.gov.au
Fri Jun 5 08:47:46 EST 1998


     In Australia we have a very simple device that fits to the front of a
     car and emmits a high frequency sound (above 20kHz one would assume)
     to deter pets.  It's proved to be very effective especially against
     kangaroos  and wombats which can pose a threat on the open road.  I
     understand it has also proved effective against pets.  It's cheap
     (about $25 Aus)

     There is another device on the market retailing for about $250 Aus
     that produces an electronic noise (again above 20K). Most people seem
     to find that the cheap option works however.


     Paul Secombe
     Senior Audiologist
     Royal Darwin Hospital


______________________________ Reply Separator _________________________________
Subject: Re: simple/cheap circuit for "dog chaser" or "ultrasonic pes
Author:  BIOSCI-REQUEST at net.bio.net at SMTP
Date:    05/6/98 9:36 AM


Hi there...

I don't have a circuit for such a device, but the military have been
experimenting with this type of stuff for years.   Any type of warble
oscillator that can generate a few hundred milliwatts into an ultrasonic
transducer should work.  You would have to go through parts cataloges for
the transducer.  Good quallity ones are expensive!   Check out alarm system
suppliers for such a piece.  Maybe you will get a good price there...

As for AC magnetic waves chasing off insects, I think that one is a lot of
hype!

As for insects,   I have read some articles that warbling sounds between
22,000 up to about 38,000 Hz annoy them to the point where they want to get
out of the area.    I don't know which ones are effected by what frequency.
One research I read about 2 years ago stated that some insects reacted more
to a sawtooth or squarewave more than to a sine wave.  The noise also must
vary in pitch and pulsate as well.

If you search the net for ultrasonics, insects, noise, bats, and other
related key words, maybe you will find something...

I hears from someone a long time ago that there was a device commercialy on
the market to do what you want.  Some people said that it was not so
effective...

Good Luck...

Greetings...
--

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============= Message Seperator ================

bigdiq at hotmail.com wrote in message <6kvsh4$3h3$1 at nnrp1.dejanews.com>...
|Hello!
|I was wondering if anyone knew of a simple, cheap circuit to create very
high
|pitched sounds (20-85khz variable would be nice).  I had a device called
"The
|Phazer" which purported to chase away dogs , it created a very high-pitched
|noise from a large metal transducer (it didn't look piezo- anyone know what
|it is?)
|I have also seen "electronic pest chasers" which suggest "ultrasonic waves"
|chase away everything from insects to rodents (they have different
frequency
|settings for insects, rodents, birds, and cats/dogs.) Does anyone know if
|this actually works on insects and birds (I've seen the effect on cats and
|dogs) and if so, what approximate frequency ranges are appropriate?
|
|Last electronics question:
|Some of these products also advertise some sort of extra effect thru some
|sort of magentic wave induced back into the home's AC wiring ("Makes your
|whole house repellant to pests!"). Can anyone explain (or venture an
educated
|guess as to how this works?)
|
|
|Thanks very much!!!
|Please reply to:
|bigdiq at hotmail.com
|
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