I have some buzzers taken from personal alarms, as you can imagine they are very loud and piercing,
I wish to make them quiet and growling.
I have had some success by lowering the supply voltage, but seem to remember a formula
about I/E=R (or something similar) which would raise the current with detriment to battery life,
Is there a better way ?
Buzzer was on 9v and checks out at 1.4 mΩ

Bazza

 

Not sure about the "growling" but I prefer to use mechanical means to quieten self-contained buzzers, i.e. cover or partially cover the sound hole(s). Lowering the supply voltage probably won't work very well.

 

if they are piezo buzzers, alter their frequency or muffle them with bluetack or other gum, if they are mechanical types, muffle tape or partially covered holes on the casing.

 

if they are piezo buzzers, alter their frequency or muffle them with bluetack or other gum, if they are mechanical types, muffle tape or partially covered holes on the casing.

Thanks for your advice,
what I would like to achieve is an imitation of a dogs growl or cats yarl ( for a cat deterrent i'm working on)
this cant be so loud as to disturb the neighbours,
is there another way to create a sound ?

 

Buy an inexpensive voice record/playback module from ebay and record the sounds of angry pets.

 

best deterrent for cats and dogs,is an ultrasound whistle using a piezo oscillator , around 40 - 80 Khz ,its outside of human hearing range but annoying for pets, plenty of circuits using a 555 chip,or cd4060.

 

both excellent ideas,
given me lots to think about.
I'm a bit green, where do I find a circuit for an oscillator,
One thing Dave, if you can't hear the oscillator how do you know it's working, LOL

 

use a scope or frequency counter to check its working,or test it on your own pet,

http://www.google.co.uk/search?q=ca...4.mobile-heirloom-serp..0.13.1810.r3ZnL0onp8I

 

You might get a better response if the title of the thread were related to the actual requirement. e.g. "Sonic pet repeller circuit wanted"

 

You might get a better response if the title of the thread were related to the actual requirement. e.g. "Sonic pet repeller circuit wanted" Sorry ! your advice noted,
money, knowledge and equipment short supply, just that I had the bits, and looking for the easy option,
and I am new to this,

Baz

 

My dad had a pest repellent system devised of his redneck engineering skills, i remember from when I was a child. My dad didn't have the tech skills to design a circuit but his device was the most effective I've ever seen. It was to keep deer out of the garden. He salvaged a broken table saw and powered it from the light socket of a motion detector lamp. Any time a deer would come near the garden, that old table saw with its broken motor mounts and worn bearings, would spin to life with the most hideous sound as it the motor and attached blade went to work trying to free itself from the rusty cage. That table saw just sat out in the weather in the garden decomposing back to dust in between scare sessions, for years. It outlasted my dad's willingness to maintain a garden, and the deer never did become acclimated to its sound, as they would with every other kind of repellent.


EDIT:
Sorry I got cot up in the anecdote and forgot the useful suggestion portion of my response. Try putting a 10K trim pot in series with the buzzer. That should give you some volume adjustment.

 

<Some text removed for clarity.>
One thing Dave, if you can't hear the oscillator how do you know it's working, LOL

(Yeah, my name is not Dave.)

Get somebody with better hearing to listen to it, use a transducer sensitive the the appropriate frequency or use a "bat detector". http://www.next.gr/circuits/NE612-heterodyne-detector-l21642.html

When I was working on an ultrasonic barking deterrent my wife who has much better hearing came into the room and asked me to turn it off.

 

An ultrasonic wife deterrent?