Dog stopping: Finding a Piezo buzzer/transducer? - Page 4 - Electronic Circuits Projects Diagrams Free

HarveyH42 · 13th March 2007, 11:47 PM

How can you be sure of what the frightened dog will do? There are few people on this planet I'd take on a vicious dog for myself. If you walk up on an alligator, you don't poke it with a stick. If you do see someone actually getting mauled, this device will need to be extremely powerful to have any effect. Load like a gun shot. Your hearing, the victim of the mauling, and the dog's will be put at risk.

Now, most dogs bark, growl, and put on an impressive display of aggression, but seldom actually bite. Most people who get attacted, seriously mauled, not just a little nip, usually provoked it in the first place. They over reacted to the warning the dog was giving, or thought they were so vastly superior to some stupid animal...

For a hand held device as you have described, you can only hope for a dog teaser. Might as well poke it with a stick. Pepper spray would be a thousand times more effective.

mneary · 13th March 2007, 11:51 PM

I thought the discussion was about a device to stop a dog from peeing on a lawn. So few of the thread messages are in their original form (due to editing), I can't confirm it.

"They" don't make a sprinkler that comes on when a dog enters my lawn, it's mine. It's not operational; it was triggered by an electric eye at 1 ft. Another electric eye at 3 ft disabled it, on the assumption that the mailman and gardener would be more than 3 ft high. (Delays are required).

Neighbor with the dog has moved, so it's no longer needed. I may hook it up again, this time to a camera, for home security.

DigiTan · 14th March 2007, 01:23 AM

This thread was never about dog barking or peeing except for the many who didn't read it. Or didn't bother asking.

Quote:

Originally Posted by HarveyH42

For a hand held device as you have described, you can only hope for a dog teaser. Might as well poke it with a stick. Pepper spray would be a thousand times more effective.

Incidentally, my sister project is an identical 1.5" x 3.3" pellet lined with Nordihydrocapsaicin and an ultraviolet dye. I'm still engineering the dispersal method.

To have any practical use, I need between 120db - 130db (sustained for under than 20 seconds to prevent hearing damage) which certainly seems plausible for a specialized piezo. My search for components might be moot if I can somehow confirm the existing products have this sound pressure.

audioguru · 14th March 2007, 02:33 AM

I don't remember the datasheet for an ultrasonic piezo in this thread that produces 119dB at 1m. Maybe the 400W tweeter with 400W.

I think a tiny 1.25" diameter piezo ultrasonic transducer would produce 119dB at a distance of only 10cm with a power input of 10W if it survives. An amplifier to produce 10W would need a pretty big and heavy battery.

Sound decreases in level 6dB with each doubling of distance. Humidity reduces high frequencies. Wind also "blows away" high frequencies. High frequencies are very directional.

119dB at 10cm.
113dB at 20cm.
107dB at 40cm.
101dB at 80cm.
95dB at 1.6m.
89dB at 3.3m.
83dB at 6.6m. That is about 20 feet and is not loud.

Is it worth it?

HarveyH42 · 14th March 2007, 03:13 AM

My last dog was a Rot mix, big dog. Wasn't real aggressive, just had a taste for pitbull. Once he was on the attack, only physical means could stop it (no easy task). I think they use very low frequencies to provoke each other. My dog's breathing would change, could almost hear something.

I know you don't want to hear anything but parts and circuits, but this stuff is also important to the design, otherwise its just a dangerously false sense of security, and more likely to provoke an attack. I've raised several dogs, mostly large breeds, couple considered dangerous (think that's mostly in how you raise them, never a huge problem). They are very quick, not 100% predictiable (have a few scars to prove it), and extremely strong. An animal in pain is a danger to everyone in biting distance, its defensive. Even the dog's owner isn't exempt.

I really don't know all the details of how and why some people get mauled by dogs. I'm not talking about a single nip or bite, but a full on attack. Never witness that sort of behavior in my dogs. Even when a male dog gives challenge for leadership rights, it's not about inflicting damage, but I learned how to play that game, maybe it's not so common.

Personally, counting on a gadget that makes noise isn't going to be enough to stop an attack in progress, and you really don't have time to fumble around for it. Best you can do is report a vicious animal, and get your neighbors involved. If the owner doesn't handle the animals correctly, they shouldn't have them.

DigiTan · 14th March 2007, 04:21 AM

1. Read my "keep it electrical" comment. Appearantly it didn't sink in.
2. Re-read.
3. If you aren't audio, nigel, torben, chemelec, jemch, mneary, Hero, or gramo; press ALT+LeftArrow and spare me these inane distractions.

That much dB loss huh? Yeah, barely justifies the cost in that case. It makes me wonder if the commercial stuff only works by being highly directional. If at all. I'll keep my eye on the piezo tweeters. They could still be useful in some other context. Maybe a car backup warning for dog owners or something. I'll do some more sleuthing and see if 119db has any application against less aggressive animals.

audioguru · 14th March 2007, 12:08 PM

Here are the spec's for the big piezo tweeter used in cheap old PA speakers. The frequency response graph has been heavily smoothed to make it look "smoother".
With a 64W amplifier, its sound pressure at 8m is not very loud.

audioguru · 16th June 2007, 03:17 PM

A single Mosfet cannot drive a piezo transducer properly. You need the drive to be push-pull. A bridged output will effectively nearly double the supply voltage for the driver circuit. A CD4047 oscillator IC has two opposed outputs for driving a bridge.

mneary · 23rd June 2007, 04:34 AM

Quote:

1. Read my "keep it electrical" comment. Appearantly(sic) it didn't sink in.
2. Re-read.

Whether you like it or not, ethics will be part of the discussion. It really is important. Deal with it.

13th March 2007, 11:47 PM
HarveyH42 Experienced Member	How can you be sure of what the frightened dog will do? There are few people on this planet I'd take on a vicious dog for myself. If you walk up on an alligator, you don't poke it with a stick. If you do see someone actually getting mauled, this device will need to be extremely powerful to have any effect. Load like a gun shot. Your hearing, the victim of the mauling, and the dog's will be put at risk. Now, most dogs bark, growl, and put on an impressive display of aggression, but seldom actually bite. Most people who get attacted, seriously mauled, not just a little nip, usually provoked it in the first place. They over reacted to the warning the dog was giving, or thought they were so vastly superior to some stupid animal... For a hand held device as you have described, you can only hope for a dog teaser. Might as well poke it with a stick. Pepper spray would be a thousand times more effective.

13th March 2007, 11:51 PM
mneary Experienced Member	I thought the discussion was about a device to stop a dog from peeing on a lawn. So few of the thread messages are in their original form (due to editing), I can't confirm it. "They" don't make a sprinkler that comes on when a dog enters my lawn, it's mine. It's not operational; it was triggered by an electric eye at 1 ft. Another electric eye at 3 ft disabled it, on the assumption that the mailman and gardener would be more than 3 ft high. (Delays are required). Neighbor with the dog has moved, so it's no longer needed. I may hook it up again, this time to a camera, for home security.

14th March 2007, 02:33 AM
audioguru Experienced Member	I don't remember the datasheet for an ultrasonic piezo in this thread that produces 119dB at 1m. Maybe the 400W tweeter with 400W. I think a tiny 1.25" diameter piezo ultrasonic transducer would produce 119dB at a distance of only 10cm with a power input of 10W if it survives. An amplifier to produce 10W would need a pretty big and heavy battery. Sound decreases in level 6dB with each doubling of distance. Humidity reduces high frequencies. Wind also "blows away" high frequencies. High frequencies are very directional. 119dB at 10cm. 113dB at 20cm. 107dB at 40cm. 101dB at 80cm. 95dB at 1.6m. 89dB at 3.3m. 83dB at 6.6m. That is about 20 feet and is not loud. Is it worth it? __________________ Uncle $crooge

14th March 2007, 03:13 AM
HarveyH42 Experienced Member	My last dog was a Rot mix, big dog. Wasn't real aggressive, just had a taste for pitbull. Once he was on the attack, only physical means could stop it (no easy task). I think they use very low frequencies to provoke each other. My dog's breathing would change, could almost hear something. I know you don't want to hear anything but parts and circuits, but this stuff is also important to the design, otherwise its just a dangerously false sense of security, and more likely to provoke an attack. I've raised several dogs, mostly large breeds, couple considered dangerous (think that's mostly in how you raise them, never a huge problem). They are very quick, not 100% predictiable (have a few scars to prove it), and extremely strong. An animal in pain is a danger to everyone in biting distance, its defensive. Even the dog's owner isn't exempt. I really don't know all the details of how and why some people get mauled by dogs. I'm not talking about a single nip or bite, but a full on attack. Never witness that sort of behavior in my dogs. Even when a male dog gives challenge for leadership rights, it's not about inflicting damage, but I learned how to play that game, maybe it's not so common. Personally, counting on a gadget that makes noise isn't going to be enough to stop an attack in progress, and you really don't have time to fumble around for it. Best you can do is report a vicious animal, and get your neighbors involved. If the owner doesn't handle the animals correctly, they shouldn't have them.

14th March 2007, 04:21 AM
DigiTan Experienced Member	1. Read my "keep it electrical" comment. Appearantly it didn't sink in. 2. Re-read. 3. If you aren't audio, nigel, torben, chemelec, jemch, mneary, Hero, or gramo; press ALT+LeftArrow and spare me these inane distractions. That much dB loss huh? Yeah, barely justifies the cost in that case. It makes me wonder if the commercial stuff only works by being highly directional. If at all. I'll keep my eye on the piezo tweeters. They could still be useful in some other context. Maybe a car backup warning for dog owners or something. I'll do some more sleuthing and see if 119db has any application against less aggressive animals. __________________ Last edited by NSA’s Echelon System: Today at 12:41 AM. * AVR Projects * Robot War [for TI graphing calcs] * Robot War TI footage

16th June 2007, 03:17 PM
audioguru Experienced Member	A single Mosfet cannot drive a piezo transducer properly. You need the drive to be push-pull. A bridged output will effectively nearly double the supply voltage for the driver circuit. A CD4047 oscillator IC has two opposed outputs for driving a bridge. __________________ Uncle $crooge