Author: sblDate: 07:29 04-10-06
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Hi,
I would like to build a home-made cat repeller, based on high pitch
sound (18-19KHz and up)
What's the simplest way to build such a sound generator?
Thanks!
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Author: Bob MastaDate: 08:49 04-10-06
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On 4 Oct 2006 04:29:32 -0700, "sbl" <sblueeye@gmail.com> wrote:
>Hi,
>
>I would like to build a home-made cat repeller, based on high pitch
>sound (18-19KHz and up)
>
>What's the simplest way to build such a sound generator?
>
>Thanks!
>
I have my doubts about how effective it would be.
But if you want to do some experiments before you
commit to buying any parts, you are welcome to
download my DaqGen freeware sound card signal
generator. You can see what works and what doesn't,
both with respect to frequency and speakers.
Note that most sound cards don't go above 20 kHz,
even though DaqGen will cheerfully generate higher
frequencies internally... you just won't get them out
of most cards.
One difficulty might be knowing how well your chosen
speaker is working at these frequencies. Might need
a young child that still has that part of their hearing
range to tell you what is happening.
Best regards,
Bob Masta
dqatechATdaqartaDOTcom
D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Home of DaqGen, the FREEWARE signal generator
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Author: BobGDate: 09:22 04-10-06
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> On 4 Oct 2006 04:29:32 -0700, "sbl" <sblueeye@gmail.com> wrote:
> >I would like to build a home-made cat repeller, based on high pitch
> >sound (18-19KHz and up)
> >What's the simplest way to build such a sound generator?
=======================================
Obviously you need a high frequrncy transducer (tweeter!). Get one of
those Motrola peizo tweeters at radio shack or the local music store.
And a regular old signal generator, maybe one with a burst mode or
sweep mode...
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Author: Leo MeyerDate: 11:35 04-10-06
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"sbl" <sblueeye@gmail.com> schrieb im Newsbeitrag
news:1159961372.485545.30120@h48g2000cwc.googlegroups.com...
> Hi,
>
> I would like to build a home-made cat repeller, based on high pitch
> sound (18-19KHz and up)
>
> What's the simplest way to build such a sound generator?
>
I once bought and built an insect repellent kit based on an astable
multivibrator. It used an earplug as a loudspeaker. The circuit is very
simple and easy to build. And there are plenty of resources available on the
net for astable multivibrators. Might be worth checking out.
Probably you will need more power and a proper loudspeaker, but I think
adding an extra transistor wouldn't be that hard.
Leo
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Author: Clyde CrashcupDate: 23:04 04-10-06
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sbl wrote:
> Hi,
>
> I would like to build a home-made cat repeller, based on high pitch
> sound (18-19KHz and up)
>
> What's the simplest way to build such a sound generator?
>
> Thanks!
>
How about a 120 db speaker?
--
50% of all statistics are wrong. The rest don't matter.
Clyde Crashcup
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BobG wrote:
> > On 4 Oct 2006 04:29:32 -0700, "sbl" <sblueeye@gmail.com>
wrote:
> > >I would like to build a home-made cat repeller, based on high
pitch
> > >sound (18-19KHz and up)
> > >What's the simplest way to build such a sound generator?
> =======================================
> Obviously you need a high frequrncy transducer (tweeter!). Get one
of
> those Motrola peizo tweeters at radio shack or the local music
store.
> And a regular old signal generator, maybe one with a burst mode or
> sweep mode...
I tried those tweeters years ago for the neighbors dog. Heathkit audio
generator, Sansui amp. Didn't do squat but it was fun fiddling around
with it.
GG
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Author: Johnny BoyDate: 00:36 05-10-06
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"sbl" <sblueeye@gmail.com> wrote in message
news:1159961372.485545.30120@h48g2000cwc.googlegroups.com...
> Hi,
>
> I would like to build a home-made cat repeller, based on high pitch
> sound (18-19KHz and up)
>
> What's the simplest way to build such a sound generator?
>
> Thanks!
>
Probably the simplest would be a '555 timer with a driver transistor or
half-bridge into a piezo tweeter
... Johnny
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sbl wrote:
> Hi,
>
> I would like to build a home-made cat repeller, based on high pitch
> sound (18-19KHz and up)
>
> What's the simplest way to build such a sound generator?
>
> Thanks!
My experience with dogs is that they do not respond to any sort of
sound by itself as a repellent or deterrent to undersirable behavior.
My bet is that cats would be the same way.
The sound has to be strongly associated with some sort of punishment,
i.e, the sound should probably immediately preceed the punishment or
occur concurrently.
Just as an example, and not necessarily a recommendation, you could for
instance rig up a cat trap and have the sound start when the trap
closes. If cats are like dogs, you would only need to do this once to
permanently "train" any individual cat.
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Author: Roger DewhurstDate: 15:59 05-10-06
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Author: Johnny BoyDate: 22:23 05-10-06
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"Roger Dewhurst" <dewhurst@wave.co.nz> wrote in message
news:eg3o60$5tc$1@lust.ihug.co.nz...
>
> "Johnny Boy" <NoSpam@Please.com> wrote in message
> news:45248b8d$0$5109$afc38c87@news.optusnet.com.au...
> >
> > "sbl" <sblueeye@gmail.com> wrote in message
> > news:1159961372.485545.30120@h48g2000cwc.googlegroups.com...
> > > Hi,
> > >
> > > I would like to build a home-made cat repeller, based on high pitch
> > > sound (18-19KHz and up)
> > >
> > > What's the simplest way to build such a sound generator?
> > >
> > > Thanks!
> > >
> >
> > Probably the simplest would be a '555 timer with a driver transistor or
> > half-bridge into a piezo tweeter
>
> Can you explain the half-bridge please.
>
> R
>
Hello Roger,
a simple bi-polar half-bridge would look something like
this:-
(View in 'Courier' or 'FixedSys'):-
+Vcc
+Vcc o
o |
| |/
| +---| NPN
+---+---+ | |> /|
| | | | C +-+ |
| '555 +----[R]---+ +---||---| | |SPKR (Piezo-Tweeter)
| | | | +++ |
+---+---+ | |< | \|
| +---| PNP |
| |\ ===
=== | GND
GND ===
GND
... Johnny
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Author: Roger DewhurstDate: 23:35 05-10-06
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"Johnny Boy" <NoSpam@Please.com> wrote in message
news:4525bdc8$0$32603$afc38c87@news.optusnet.com.au...
>
> "Roger Dewhurst" <dewhurst@wave.co.nz> wrote in message
> news:eg3o60$5tc$1@lust.ihug.co.nz...
> >
> > "Johnny Boy" <NoSpam@Please.com> wrote in message
> > news:45248b8d$0$5109$afc38c87@news.optusnet.com.au...
> > >
> > > "sbl" <sblueeye@gmail.com> wrote in message
> > > news:1159961372.485545.30120@h48g2000cwc.googlegroups.com...
> > > > Hi,
> > > >
> > > > I would like to build a home-made cat repeller, based on high pitch
> > > > sound (18-19KHz and up)
> > > >
> > > > What's the simplest way to build such a sound generator?
> > > >
> > > > Thanks!
> > > >
> > >
> > > Probably the simplest would be a '555 timer with a driver transistor
or
> > > half-bridge into a piezo tweeter
> >
> > Can you explain the half-bridge please.
> >
> > R
> >
>
> Hello Roger,
> a simple bi-polar half-bridge would look something like
> this:-
>
> (View in 'Courier' or 'FixedSys'):-
>
> +Vcc
> +Vcc o
> o |
> | |/
> | +---| NPN
> +---+---+ | |> /|
> | | | | C +-+ |
> | '555 +----[R]---+ +---||---| | |SPKR (Piezo-Tweeter)
> | | | | +++ |
> +---+---+ | |< | \|
> | +---| PNP |
> | |\ ===
> === | GND
> GND ===
> GND
>
> ... Johnny
Thanks. I see.
Roger
>
>
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Author: sblDate: 05:38 08-10-06
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Johnny Boy wrote:
> Hello Roger,
> a simple bi-polar half-bridge would look something like
> this:-
>
> (View in 'Courier' or 'FixedSys'):-
>
> +Vcc
> +Vcc o
> o |
> | |/
> | +---| NPN
> +---+---+ | |> /|
> | | | | C +-+ |
> | '555 +----[R]---+ +---||---| | |SPKR (Piezo-Tweeter)
> | | | | +++ |
> +---+---+ | |< | \|
> | +---| PNP |
> | |\ ===
> === | GND
> GND ===
> GND
>
> ... Johnny
What's the effective range of such a speaker? Do you have any prefered
tweeter model?
Thanks,
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Author: Bob MastaDate: 10:04 08-10-06
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On 8 Oct 2006 02:38:02 -0700, "sbl" <sblueeye@gmail.com> wrote:
>
>What's the effective range of such a speaker? Do you have any prefered
>tweeter model?
You might check www.partsexpress.com for tweeters.
They have a big selection and good prices. The problem
with most tweeters is gettting frequency response information.
Speaker manufacturers don't seem to use the normal -3 dB
points to define the frequency range. I'm not sure what
criteria they use, but I suspect that it includes a lot of hype.
So, don't believe specs like "2000 to 25000 Hz" unless
they specify "-3 dB", which they rarely do. Look for an
actual curve.
Having said all that, piezo tweeters are probably your best bet
if you can't get better info. They tend to have extended high
ends, though don't expect them to be flat. (Nothing is very
flat at these high frequencies, except maybe electrostatics,
and they have other issues.) Piezo tweeters are capacitive
loads, with typically pretty high impedance. The efficiency
numbers never look too good (typically low 90s for dB SPL
at 1 watt and 1 meter) compared to dynamic drivers, but
I think that may be because they are not measuring actual
power input to the drive, but using an equivalent 8 ohm
calculation with the drive voltage. However, if the actual
(high) impedance is considered they would be much more
efficient. (By the same token, the maximum "power" handling
in the specs is also based upon the same fiction, so you
aren't going to actually stuff 50 watts or whatever into any
piezo tweeter... they just mean that it's appropriate to use
as the tweeter with a 50 watt amp driving the overall speaker
system with normal program material.)
On the PartsExpress website, look under individual tweeters
for specs. I don't recall if there are any response curves
for piezos, but under one of them there is a PDF from CTS
explaining all the fundamentals and how to calculate the
crossover cap, how to use them in series and parallel, etc.
If the underlying concept has any merit, then for good
dispersion you might want to go with an array of piezos
angled in different directions. You might want to buy an
assortment of cheapo models to test, then when you find
one you like buy a whole mess of them. They have models
priced from under a dollar, in bulk.
Best regards,
Bob Masta
dqatechATdaqartaDOTcom
D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Home of DaqGen, the FREEWARE signal generator
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Author: BobGDate: 11:08 08-10-06
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Good answer Bob, especially if his question was about 'frequency
range', but for some reason, I though he might be asking about
'distance' range, like, from how far away will it annoy the cats? The
answer to this depends on how good the cats hear, and how loud the
noise is. I think you can put a 25V square wave into those motorola
piezos, and at a human audible frequency like 4khz, they are too darn
loud to listen to for more than a few seconds at arms length. Assuming
they are still that loud at 20khz, I guess we assume they get about 6db
quieter every time you double the distance. But to test it, you need to
blare it into a cat about 3 feet away and see if he runs away. Then you
need to repeat, doubling the distance each time until it becomes
ineffective, or until you become shredded from claws.
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Author: Johnny BoyDate: 20:30 09-10-06
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"sbl" <sblueeye@gmail.com> wrote in message
news:1160300281.941592.196640@b28g2000cwb.googlegroups.com...
>
> What's the effective range of such a speaker? Do you have any prefered
> tweeter model?
>
> Thanks,
>
Range is something you'll need to determine by testing. The simple
circuit that I drew would not produce much power, so the range would not be
great. A bit of trial and error would be needed to find the right frequency,
too. Regarding tweeter models, I vaguely remember that a Motorola tweeter
was recommended once for this type of application, but I can't remember what
model.
I should point out that I personally don't think that these things are
very effective. From what I've heard, some people claim that they work and
others say they don't. I've seen similar devices marketed either as
electronic dog whistles or as 'bark stoppers'.
... Johnny
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