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Any ideas for an Ultrasonic pulse generator?

3/2/2004 11:05 AM
Any ideas for an Ultrasonic pulse generator?
Hi guys,  
I've got the perennial problem of neighbour's dogs that bark incessantly just before dawn. I'm thinking of building a gizmo that will emit an ultrasonic pulse/burst at suitable enough levels to send Fido bolting under the house. He lives about 60 to 70' from my bedroom so I'm reckon some form of parabolic reflector may help - or maybe somekind of "sonic barrel" (like a length of pipe).  
Somewhere between 17k and 20kHz should be sufficient, amplification isn't a problem (gotta a bunch of KT88s ;) ), but what kind of transducer/speaker? I'm guessing a piezo....but maybe you might have a better suggestion?  
I have seen some commercially available "Stop barking dogs" gadgets but they're only good for around 20' and don't appear to be to well focused. I don't want the mutt's ears to bleed (although in the early hours the desire has had some appeal) and I don't really want to send out large random blurt to upset any nice, sleeping dogs....although collateral damage in the name of a good night's sleep may be considered.  
3/2/2004 6:53 PM
John Fisher

I have several circuits for repelling rats and insects.  
They operate at about 25kz to 50kz.  
The thing is, what if the poor thing is tied up and can't get away. You may wake up in the morning to find all of the animal life in the area either gone or dead.:D  
Yes, a piezo electric transducer would be in order as it can reach those frequencies to where the normal speakers won't. You can build something and then put any size amp you want up to it.  
I had the same problem in my niegborhood with dogs barking and I just prayed real hard and it has been better ever since. :)  
Now I have to work on a large parote that lives next door. His favorite sound to imitate is a car horn and boy is he LOUD!! I got him to whistle at girls for a while be he keeps going back to the car horn. :(  
John Fisher
3/3/2004 10:39 AM

Thanks John :)  
The dog in question isn't tied up - just left to roam it's fenced yard at all hours, which is fair enough I guess. The problem is that in the early hours Wallabies venture out of the neighbouring National Park to graze in the backyards and Fido can't cope (neither can Pete ;))  
I've watched this dog bolt (like most dogs do) at the sound of a thunder clap - so a high frequency "thunder clap" seems the order of the day (morning to be exact).  
An oscillator is pretty straight forward. It would be nice to drive the piezo with something battery powered but I don't know if I could get enough output (however short the duration) to achieve the required level.  
'Tennyrate, thanks for the support - and good luck with the parrot! :D  
3/3/2004 6:49 PM
John Fisher

One circuit that I have has 2 ocilators. ( I think). One is a hight pitched sound created by a 555 timer or something and the other is low frequency which couses an obnoxious bursting effect to the rats.  
When I lived in Argentina I was in a rural area for a while.  
For some reason there was a plage of rats for a season. I mean, I have never seen so many rats in my life. You would go out at night and turn a light on and there were literaly hundreds of rats in the trees eating the berries.  
I caught one and put it in a cage for experimetation.  
I built a rat repeller circuit.  
I put it near the rat in the cage to see what would happen. Everytime I flipped the switch the rat would jerk. I thought: ah ha! great! It works. I then realized later that it was the sound of the mecanical switch that was flipped that scared the rat and made him jerk. :D  
The next day I went to the cage for further experimentation and he mannaged to make a hole and get away. :(  
John Fisher
3/3/2004 9:22 PM
Frank DeSalvo

Haha, this thread is a real treat :D! Yes, let's get a schemo drawn up! There are a ton of dogs around my house that bark incessantly at all hours of the night. In this instance, the humane-factor doesn't matter. If you guys can come up with something to melt them down, I'd fire it right up! :D  
3/3/2004 10:38 PM
bob p Idea for an Alternative Solution
I’d like to offer some help on this topic from a different approach. Having trained some assistance dogs for the handicapped, I’d like to suggest that everyone take most intelligent approach to the solution as possible.  
Dogs are incredibly intelligent and highly trainable animals and they will go out of their way in an effort to please anyone that they have respect for. Only two conditions are required to achieve this type of goal: first, you must gain the respect of the dog, and second, you must succeed in communicating to the dog what type of behavior you want it to perform. In most human-dog relationships, the difficult part of the equation isn’t the limited intellect of the dog – it’s the fact that most humans don’t understand how to effectively communicate their desires to the dog. As a result, 99% of all of dogs are largely untrained animals who have lots of potential to learn new skills.  
From an animal behaviorist standpoint, when training a dog to bark and not to bark, the first thing to consider is whether or not the dog is exhibiting appropriate barking behavior.  
Dogs that are confined, especially in a fenced yard, will exhibit perimeter-based anxiety when: 1) they are threatened and confinement prevents them a route of escape, and 2) other animals trespass on their territory and confinement prevents them from being able to do anything about it.  
So the question arises of whether or not is appropriate to punish a dog that is exhibiting appropriate behavior. Perhaps a more humane solution would be to train the dog (or the owner) to exhibit a new and more desirable appropriate behavior instead of continuing to exhibit the old and "undesirable" but still appropriate behavior.  
Unfortunately, there are a number of impediments to accomplishing this goal, even for the best dog-whisperer. Even if somebody was dedicated enough and educated enough to undertake such a project in operant conditioning, it would optimally require the assistance and approval of the owner. Its still possible to train another person’s dog without their knowledge or consent, but its much easier if you have a cooperative owner. Unfortunately, as we all know, its one hell of a lot easier to fashion a weapon to punish the animal, as it requires infinitely less intelligence on our part and consists of the very desirable path of least resistance. It also provides instant gratification to those who like to wield a complex and invisible weapon in order to inflict pain on a defenseless animal without much fear of being caught.  
A more humane approach to the problem would be to give the dog an option, like training the dog not to bark at the appoaching game. Instead, the dog should be trained to exhibit a different/substitute behavior in that situation. This could be a bit challenging, as barking is a self-reinforcing behavior to the dog. Operant conditioning is the key to success in this sort of behavior modification – some sort of reward that the dog enjoys more than barking should be offered to reinforce an alternate behavior which is mutually exclusive with barking. Optimally, after this sort of conditioning takes place, the dog should be additionally trained with a command like “enough” that would be the dog’s cue to cease barking. Unfortunately, most humans’ appreciation of dog training is limited to yelling “SHUT UP” at a barking dog. Not surprisingly, the hostile approach yields very limited success.  
I have a couple of examples that may help to illustrate these points:  
First, my dog used to hate the approach of the mailman and the newspaper delivery boy. The dog had a very strong protective/guarding drive, and would sit by the front door at the usual hour in anticipation of the approach of these “intruders.” After lying in wait, he would bark menacingly at their approach.  
The key to successfully modifying this behavior was to train the animal to perform a different behavior and then to desensitize the animal to the approach of the “intruders.” First, I trained the dog that it was unacceptable to charge the door when they approached. Instead, I trained the dog to lie down in the hallway and bark from that location. Then, once the dog was trained to move to his designated spot, I taught him to stop barking by using the “enough” command, and by reinforcing silent behavior. This effectively communicated to the dog that I preferred silence during the approach of an intruder. As a result, the dog’s behavior was modified so that he preferred to lie silently in wait while an intruder approached.  
Then, once the dog was trained to move to a designated spot and remain silent, I began to provide him treats as the “intruders” approached the house. It took some time, but he effectively learned to associate treats with the approach of the paperboy and the mail carrier. Friendly behavior toward them ensued. Now he loves the paperboy and the mail carrier, and lets both of them approach the house without incident.  
All that was necessary to perform this behavior modification was to think through what behaviors could be used to form a “bridge” between the behaviors that the dog was already exhibiting and the behavior that was desired from the dog. Then, by “chaining” multiple behaviors in a stepwise fashion, it was possible to train the dog to perform a complex task and substitute one group of behaviors for another.  
As a second example, I had a similar barking problem with a neighbor’s dogs. They lived in a fenced yard and would bark menacingly every time that I went to my storage shed that was near the boundary of their yard. To train them not to bark at me, I just called them by name, told them that they were good dogs, and gave them treats when I approached. Now these dogs approach me with wagging tails as if I were their master. In this situation, the dog’s real owner preferred to leave his dogs outdoors and unsupervised, and he was was completely out of the loop, blissfully unaware that I was retraining his dogs to exhibit more appropriate behavior.  
The biggest impediment to training a dog to perform a complex task lies in the failure of most people to analyze complex behavior and to break it down into a series of small, but easily trainable tasks that the dog is capable of mastering. Then, once the dog has learned each individual task, all that’s required is to “chain” one task into another. Once you understand how do to it, all that is required is patience. Its really not that hard to train your dog to open the refrigerator, take out a beer, set it on the floor, close the refrigerator door, pick up the beer, and bring it to you. It took my dog a couple of days to learn the trick, one step at a time.  
Similarly, it shouldn’t be that hard to train the neighbor’s dog not to bark. All that you need to do is understand why the dog is barking, and understand how you can provide the dog with an alternate form of behavior that you find acceptable. Of course, its one hell of a lot easier to just torture the animal because you can’t think of a better solution.  
Perhaps the biggest risk in taking the ultrasonic generator approach is that the dog’s hearing is directional – it will be easy enough for the dog to determine where the punishment is coming from. The dog is intelligent, and in all likelihood, the dog will associate you with its punishment. As a result, you will only succeed in training the dog to hate you. If I were concerned about my own safety, I wouldn’t take that approach.  
Best of luck.  
3/4/2004 3:07 AM
Steve A.

To train them not to bark at me, I just called them by name, told them that they were good dogs, and gave them treats when I approached.  
    I kinda use the same approach when I am working at a house with a dog around but no owner... only I don't bring them treats. :(  
    I don't usually know their name but I tell them that they are a good dog for having barked at me (that's their job!) but they can stop now because I'm a friend.  
    There was one little dog who didn't like me at all... he tunneled under a house to get to the backyard where he started yapping at me and would not stop. Well, I had walked into HIS front yard thinking that I could get to the AC that way so he considered me to be a mortal enemy. ;)  
Its really not that hard to train your dog to open the refrigerator, take out a beer, set it on the floor, close the refrigerator door, pick up the beer, and bring it to you. It took my dog a couple of days to learn the trick, one step at a time.  
    Most guys try to train their wives to do that but I guess you had better luck training your dog! ;)  
Steve Ahola

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