Dog stopping: Finding a Piezo buzzer/transducer?

[mvadu]

And what is the OP-Amp IC used in that circuit?

 

[audioguru]

And what is the OP-Amp IC used in that circuit?

My circuit doesn't use opamps. It uses two of the 6 inverters in a CD4069 hex (6) inverters Cmos logic IC.

 

[Nigel Goodwin]

My circuit doesn't use opamps. It uses two of the 6 inverters in a CD4069 hex (6) inverters Cmos logic IC.

It's also clearly labelled on the circuit!.

 

[Hero999]

Also a coil in parallel can increase the power factor and therefore the efficeincy by effectively recycling the wasted capacitve current.

 

[audioguru]

One time I had a 240VAC fan that wouldn't run on my 120VAC mains. So I tuned it to my mains frequency with a capacitor in series and it ran fine. It developed about 190VAC.

I have never tried "tuning" a piezo transducer with a coil in series to increase its power.

A coil in parallel would not allow the piezo transducer to draw much current because then it would be in a high impedance tuned circuit, wouldn't it?

 

[DigiTan]

Sounds like this coil is worth looking into then. Is the voltage-doubling still likely to work the same after the circuit is tuned?

 

[audioguru]

If the AC source impedance is very low and the resistance of the coil is also very low then the coil in series with a capacitor will be a very low impedance at resonance and a very high current will flow in them.

 

[mneary]

I have a water-powered ultrasonic transducer in my yard: the sprinkler system. Very loud high pitched hissss while the air is being flushed out. Advantage is that if they don't respect the sound they'll respect the water.

 

[Hero999]

One time I had a 240VAC fan that wouldn't run on my 120VAC mains. So I tuned it to my mains frequency with a capacitor in series and it ran fine. It developed about 190VAC.

Good idea.

A coil in parallel would not allow the piezo transducer to draw much current because then it would be in a high impedance tuned circuit, wouldn't it?

It wouldn't make any difference to the piezo, but it would to the driver; the driver will see a higher impedance load but still supply the same current to the piezo. Just like the parallel power factor correction capacitor in a fluroscent ube fitting; the tube might draw 1A but the with the capacitor the totaly load on the supply might only be 0.4A.

 

[mneary]

You need to measure the reactance of the piezo at the output frequency and put a series reactance to counteract this, forming a low impedance load.

This could result in a high output, an overloaded driver, or a shattered piezo.

 

[gramo]

This project definitely has a great use! Well for me anyhow, thanks for the idea

 

[DigiTan]

Thanks, gramo. A device like this could easily prevent a dog mauling or at least mitigate one if nothing else. I'm going to fashion it into a pellet shape that can be dropped or thrown after activation if the situation merits. Although, I'll try not to get too far ahead of myself until I have the key component.

You need to measure the reactance of the piezo at the output frequency and put a series reactance to counteract this, forming a low impedance load.

This could result in a high output, an overloaded driver, or a shattered piezo.

So about this reactance measuring... Would that be done using a scope and wave generator?

 

[jemch72]

transducer

**broken link removed**

the right name is piezo tweeter , this ones respond 30 khz and 200 to 400 watts, and note, this are cheap ones, long time ago i got ones that went up to 45 khz...
but 30 khz will do some damage anyway at 200 watts, try to do a variable freq oscillator, so you go from let say 25khz up and down to 30khz...so they dont get used to the same sound tone all the time
I found a device for strong sound and ultra sound that even caused nausea to humans, never got it or built it, but I remember the seller was www.amazing1.com

 

[audioguru]

Those cheap piezo tweeters have a few strong resonances but most of their response is low.
They are fragile and cannot be driven continuously by an oscillator.
They are very directional, their sound beam is very narrow.

 

[jemch72]

Cheap response to the post

they are cheap, I wanted to show him what I was talking about, I know, you guys know everything...but you never help posting what you know...and you have all the time to find the buts , without solving the but....
https://www.usspeaker.com/cts index-1.htm
digitan, take a look at that link ...

 

[audioguru]

A tweeter is supposed to play short duration high frequency sounds like CH, CH, and SS. Continuous power would destroy it. Those cheapo piezo tweeters are just horrible-sounding whistles. They play only a few high frequencies.

Post the datasheet showing their frequency response. You won't find it because their response is so bad. Or you might find a frequency response graph that is heavily smoothed to make it look like the thing makes a wide smooth range.

They are cheap enough to try sweeping frequencies with continuous power and increasing the power until the dogs run away or the tweeter breaks. Then just double the number of tweeters and try again.

 

[Nigel Goodwin]

Audioguru seems to have a thing about piezo tweeters?, they are widely used in high power PA systems, and perform perfectly well - and are almost indestructible - I would suggest they are perfect for high power use as required for this project. Admittedly they are directional, but so are all tweeters - just use three or four angled slightly apart to give a good spread.

Apparently there are some cheap crappy imitations of the original Motorola/CTS versions?, perhaps Audioguru has experience of those?.

 

[audioguru]

I have seen and heard many high power PA systems. Cheap American speakers had the original Motorola piezo whistles blown up and Japanese copies were just as bad.

I think Bose PRO sound systems are the worst sounding. Toronto has a hockey arena with their sound system. Their expensive home systems with the satellite speakers with a speaker from a clock radio inside and a little 4" sub-woofer in a plastic enclosure also sound pretty bad. They cheat and make their demo systems much better than the junk they sell. Look on Google for Bose-bashers.

 

[jemch72]

http://www.williamson-labs.com/sdi.htm

 

[Sceadwian]

I'm surprised that no one has mentioned that this project is inhumanly cruel to the dog and doesn't punish the real culprit, it's owner. If you want to do something about a barking dog, call the police EVERY SINGLE TIME it barks excessively. Your problem WILL be solved in a few weeks one way or another with no electronic gadgetry that punishes an animal that has no idea what is causing it great pain and probably has a reason to be barking.