Dog stopping: Finding a Piezo buzzer/transducer? - Page 3 - Electronic Circuits Projects Diagrams Free

gramo · 11th March 2007, 10:27 AM

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

DigiTan · 12th March 2007, 08:45 PM

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.

Quote:

Originally Posted by 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.

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

jemch72 · 12th March 2007, 09:41 PM

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 · 12th March 2007, 10:25 PM

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 · 13th March 2007, 12:12 AM

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....
http://www.usspeaker.com/cts%20index-1.htm
digitan, take a look at that link ...

audioguru · 13th March 2007, 12:39 AM

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** · 13th March 2007, 12:52 AM

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 · 13th March 2007, 01:11 AM

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 · 13th March 2007, 01:33 AM

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

Sceadwian · 13th March 2007, 01:46 AM

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.

mneary · 13th March 2007, 04:20 AM

That's one reason I really prefer the sprinkler solution. The owner hates the water more than the dog does.

Even if the dog is off-leash, he brings the wetness home.

DigiTan · 13th March 2007, 10:42 PM

Quote:

Originally Posted by 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.

Excellent. Next time I witness a mauling, I'll tell myself "Okay, some poor fellow's getting chewed apart. But at least the owner will get community service." Sorry that doesn't fly for me. Before this topic gets hijacked, I should point out this isn't up for debate. And I'm not asking for approval. If anyone with beef wants to a mano a mano in PM, have at it. But leave my topic for electrical aspects only.

Thanks for the piezo tweeter data. I will have to stick with the smallest tweeters available if I want it to fit the casing though. The max horn radius I can install is only 1¼ inch--if they make tweeters that small. The power source is my typical a 12V Vinnic Alkaline (subject to change).

I bought new 2N4124 & 2N4121 transistors for the back-to-back emitter followers. I think thier hfe is like 160 or 200. Is that a good range for these piezo components?

@ mneary. LOL, I thought you joking about that water thing. Didn't know they really made that.

audioguru · 13th March 2007, 11:49 PM

You are making a micro ultrasonic device to scare ants at a distance of 10cm.
A piezo tweeter only 1.25'' is way too small.
A tiny 12V battery that weights only 4 grams and has a normal current of only 0.05mA is also way too small.

We were talking about enough power that might burn out a 100W tweeter and using 12V at nearly 10 Amps. To scare dogs at a safe distance.

DigiTan · 14th March 2007, 01:21 AM

I think the 0.05mA figure was used in their capacity estimate. The unrelated, optical portion of this device already drew a much higher current. I could switch to lithium or LiPoly cells as needed. I borrowed this wicked LiPo cell once that put out 7A continuous. 10A peak.

So basically, I'm stuck using piezo buzzers? I did notice the repellers on the market use a transducer comparable to the mini 40kHz ones I have generating 119db.

Slightly off-topic:
1. Can a typical PC record audio near 20kHz?
2. How rapidly will 20kHz attenuate in open air? I need 10-20ft
3. Any schematics to get a "push-on push-off" action out of a momentary pushbutton?

Sceadwian · 14th March 2007, 01:32 AM

Digi, we're talking about a dog barking, not biting. I can understand a device being constructed to protect against violent dogs, but it would have to be key chain sized to be practically usable. jemch72 has transducers and device links aren't practically portable for defense purposes.
If there's a dog with a known behavior issue owner derived or not the same common sense rule applys, repeatedly call the police and file complaints with the local SPCA or animal control facility. The problem will rectify itself with diligence.
If you're trying to create a device that can protect a person from a totally random dog attack it's pointless, the human would be bitten before they could even reach for the device.
The practicality of the perceived problem has to be applied to the construction of the device.
A dog actually in the act of attacking a human being to defend itself (weather or not the attack is perceived as defense) is not going to be detered by a simple acoustical device.

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11th March 2007, 10:27 AM	#31
gramo	This project definitely has a great use! Well for me anyhow, thanks for the idea __________________ digital-diy.com - Hobby microcontroller projects and tutorials. Assembly, PICBasic and C examples.

12th March 2007, 09:41 PM	#33
jemch72	transducer 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

12th March 2007, 10:25 PM	#34
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. __________________ Uncle $crooge

13th March 2007, 12:12 AM	#35
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.... http://www.usspeaker.com/cts%20index-1.htm digitan, take a look at that link ...

13th March 2007, 12:39 AM	#36
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. __________________ Uncle $crooge

13th March 2007, 12:52 AM	#37
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?. __________________ PIC programmer software, and PIC Tutorials at: http://www.winpicprog.co.uk

13th March 2007, 01:11 AM	#38
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. __________________ Uncle $crooge

13th March 2007, 01:33 AM	#39
jemch72	http://www.williamson-labs.com/sdi.htm

13th March 2007, 01:46 AM	#40
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. __________________ "Because I be what I be. I would tell you what you want to know if I could, mum, but I be a cat, and no cat anywhere ever gave anyone a straight answer, har har."

13th March 2007, 04:20 AM	#41
mneary	That's one reason I really prefer the sprinkler solution. The owner hates the water more than the dog does. Even if the dog is off-leash, he brings the wetness home.

13th March 2007, 11:49 PM	#43
audioguru	You are making a micro ultrasonic device to scare ants at a distance of 10cm. A piezo tweeter only 1.25'' is way too small. A tiny 12V battery that weights only 4 grams and has a normal current of only 0.05mA is also way too small. We were talking about enough power that might burn out a 100W tweeter and using 12V at nearly 10 Amps. To scare dogs at a safe distance. __________________ Uncle $crooge

14th March 2007, 01:21 AM	#44
DigiTan	I think the 0.05mA figure was used in their capacity estimate. The unrelated, optical portion of this device already drew a much higher current. I could switch to lithium or LiPoly cells as needed. I borrowed this wicked LiPo cell once that put out 7A continuous. 10A peak. So basically, I'm stuck using piezo buzzers? I did notice the repellers on the market use a transducer comparable to the mini 40kHz ones I have generating 119db. Slightly off-topic: 1. Can a typical PC record audio near 20kHz? 2. How rapidly will 20kHz attenuate in open air? I need 10-20ft 3. Any schematics to get a "push-on push-off" action out of a momentary pushbutton? __________________ The most-hated young engineer in America. * AVR Projects * Robot War: TI * About Last edited by DigiTan; 14th March 2007 at 01:23 AM.

14th March 2007, 01:32 AM	#45
Sceadwian	Digi, we're talking about a dog barking, not biting. I can understand a device being constructed to protect against violent dogs, but it would have to be key chain sized to be practically usable. jemch72 has transducers and device links aren't practically portable for defense purposes. If there's a dog with a known behavior issue owner derived or not the same common sense rule applys, repeatedly call the police and file complaints with the local SPCA or animal control facility. The problem will rectify itself with diligence. If you're trying to create a device that can protect a person from a totally random dog attack it's pointless, the human would be bitten before they could even reach for the device. The practicality of the perceived problem has to be applied to the construction of the device. A dog actually in the act of attacking a human being to defend itself (weather or not the attack is perceived as defense) is not going to be detered by a simple acoustical device. __________________ "Because I be what I be. I would tell you what you want to know if I could, mum, but I be a cat, and no cat anywhere ever gave anyone a straight answer, har har." Last edited by Sceadwian; 14th March 2007 at 01:36 AM.