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

[John Lundgren]

bigdiq at hotmail.com wrote:

> 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?)

This is all marketing hype.  Most people that I've talked to said that
they don't work.  I found one in the trash, and tore out the PC board to
use the circuit, which was a pair of 555's.  The circuit board was
labeled "PANASONY".  Now does that give you any idea of the credibility
of the company?  Incredibly lame.

You want a circuit, do a search in critter ridder, which is the one I
posted a few years ago.  I've been told that it doesn't do anything.  Go
figure.

> Thanks very much!!!
> Please reply to:
> bigdiq at hotmail.com


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