Help with ultrasonic transducer assembly

[JCDoherty]

Hi, I'm looking for some help. I don't know a thing about electrical engineering except what I've been reading trying to learn about this stuff to solve my problem. I'll tell you for me its like reading something that has been translated into Chinese then to Greek then back to English by a Russian guy.

I'd like to build an ultrasonic dog repeller, I know they are sold all over but those are poorly built or are weak or the frequency is not variable.

The situation: My neighbor across the street has two dogs that have now grown up and she takes them out for a walk twice a day. She let's them roam on retractable leash and do as they please even though our homeowners association has rules against this behavior. She, her husband and close friends are all on the homeowners board. When I politely asked her to keep her dogs out of our yard she went ballistic and finished by telling me if I complained she would make life unbearable (not the word she used) for me. Now every day she walks the dogs over to the edge of our yard and releases those extend a leash, about 25ft and I'm about to have another heart attack over it.

I've tried all the "home" remedies from ammonia, vinegar, citrus, cayenne pepper even mothballs ( I bored holes in the ground and placed them subsurface, I'm not going to hurt any animal, pet or wild.)

Nothing is working so I want to build a powerful ultrasonic repeller that operates on a variable high frequency that starts above 19khz or 20khz so it is inaudible to the neighborhood yet will force the dogs down or up the road instead of coming onto our property.

How would I go about building the thing that generates the signal and what transducer would be best suited to throwing a signal/pressure wave about 30ft, can't put them any closer to the road, so that it is unbearable for the dogs to come into the yard? Similar to walking towards one of the monster speakers at a concert and its just too much to get any closer type thing. I'd really appreciate help with this problem. I'm retired so limited funds for sure but if I can get this to work I'd be happy to donate something to the board or a charity to show my gratitude. Thanks! Jim

 

[schip666!]

I had a similar problem with a neighbor who left her two small helpless barking dogs outside pretty much 24/7. I build my Dog-Buster(TMnot) out of a 555 timer, a big transistor, and a couple piezo tweeters leftover from a speaker building project. I'm not entirely sure that it had any effect on the dogs over the long term, but it made me feel better to think that it did...

If you don't know the Chinese-Greek-Russian-English dialect I don't think this would be a happy project for you, unless you are looking to make a career change to EE or become a ham operator. But you could start by looking at tweeters at my fav surplus outlets:
http://www.goldmine-elec.com/
http://www.allelectronics.com/
and also see if they have an oscillator kit that will run at 25-30KHz, somewhat above audio. Then you will need a 12-24v power supply and an NPN power transistor in a "common-emitter" layout to drive the speakers.

Maybe there's a nerd-kid in the neighborhood who hates the HOA as much as you who could be co-opted to the dark side?

 

[Mike_In_Plano]

I tried ultrasonics once, and it didn't make much difference. Personally, I'd love to be able to tie my sprinklers in with intrusion detection. I don't care about the dogs much. All told, they've never done anything worth raising my blood pressure

However, I detest people mucking about in my yard. The code complaince people are the worst. If they find it difficult to bring in enough violations, they feel free to walk into the yards, peek over the fences, and just generally do as they please.

Perhaps some electronics monitoring combined with the sprinklers?

 

[schip666!]

Porch-light "motion sensor" connected to automatic sprinkler valve? Then you just have to make it distinguish between Friend and Foe...

Oh, the over-the-fence problem is still to be addressed. Probably higher fences.