High frequency 25-45kHz sound generator circuit, where to buy ready made?

[harvestmouse]

Hello All. First post here. Forgive me if it's in the wrong place. My knowledge of electronics can be written on the back of a stamp.

I have a project in mind. Need to generate sound between 25 and 45kHz. Variable DC voltage, say 3-15v (if my understanding of Piezo is correct in that if you want it louder, you give it more volts). I can sort out the power at one end and the Piezo buzzers at the other end, but I need to buy the middle bit.

Where can I get (in Europe) the required circuitry ready made? Doesn't have to be in a case, just with nothing to solder.

Thanks in advance. I can rewire a house and mig-weld cars, but you can see what's going on there, unlike electronics.

 

[audioguru]

Ask about the Dog Silencer Max in Google.
Some articles say it is a scam and other articles say it works well but they do not say how much they were paid to say that.

 

[Nigel Goodwin]

I'd still be interested to know how the D.S.Max functions, if anyone knows.

You're still assuming it does work? - how do you expect people to tell you how something works, when it most probably doesn't work at all.

If you believe it works, then buy one and try it.

 

[audioguru]

A dog barks or a motorcycle drives past then the high frequency is produced, is heard by the microphone and causes continuous high frequencies until it is turned off.

My daughter bought a "keys detector" that did that. You whistle and the keys detector beeps to let you hear where it is. But its beep continued forever.

 

[harvestmouse]

I'm not assuming that anything works.

At the same time, I'm not assuming that the entire global ultrasonic anti dog bark industry is a massive fraud.

The detection circuit (last one on page via previous link) with the 555 timers, was designed to, I think, switch on for five seconds (adjustable?) each time, then switch off.

Thanks for mentioning key detectors.
I remember those from the 1980s. Didn't think of it before, but it's the same principle isn't it? Detect noise, go beep.

 

[harvestmouse]

It has a rating on amazon of 2.6/5

So half of the people say it works, the other half don't. Won't be buying one of those either.

If I could just get a couple of detector circuits made, it would be a start.

Thanks anyway, I have learned some things.

 

[BR-549]

I would suggest this. Acquire a two channel function generator, a spare speaker, a non powered microphone, and a scope. Two rooms in your house an the target dog.

You can purchase a foreign 2 channel function generator for under 100 bucks. You should do this anyhow.

Don't worry about the speaker or microphone bandwidth, for now. The proximity should work.

Connect the speaker between the generator outputs. Set the outputs for a 180 degree phase difference.

Connect microphone to scope in other room. With dog.

Turn on generator, look for signal on scope. You might have to aim speaker and microphone to catch reflection. Adjust F of generator until dog reacts, if it does.

If the premise works, then you can built the unit with the proper F oscillator, amp and transducer.

If it does not work, you have added a very valuable instrument for the future. And will have to look for another solution.

 

[harvestmouse]

Thank you for the above advice, some of which I understood.

The only problem would be acquiring the dog. It's not my dog. If it was, it wouldn't bark.

I do still have a plan. Not quite like the original, but I would still need the detector circuit, with an electret microphone. There are various levels of sensitivity, so I'd have to try a few out.

Any advice is always gratefully received.

I did read a story (unconfirmed but credible) from the USA, which, for once, wasn't "shoot it". The neighbours installed a traditional microphone, amplifier and hifi speakers pointing at the offending dog owner's house. Every time the dog barked, the sound was amplified to be four times as loud and sent right back where it came from. When the police arrived, they said that (see chain of causation) the dog owners were responsible and the neighbour was right within the law.

However, as fun as that might be, I prefer the discrete path.

 

[audioguru]

Don't you have other neighbors who will hear your amplified sounds?
Won't the microphone hear the amplified sounds and create acoustical feedback continuous howling?
If you have a street then the "amplifier sounds" will not only be the dog, it will also be motorcycles and noisy cars.

 

[harvestmouse]

Misunderstanding perhaps.

My plan is completely unrelated to the story about the hifi amplifier.

 

[BR-549]

A quality built microphone probably won't work. You need a cheap non powered one. Attaching it to a scope, is your detector. One can F sweep the speaker, for it's bandwidth. After you find a sloppy speaker that will allow those high frequencies thru it........the sweeping can be used the see the microphone bandwidth on the scope. Generator and speaker in one room, the transmitter......and scope and microphone in another room, the receiver/detector. It's all sound waves, just a little higher than normal. It's all audio. No expensive equipment needed to play with it. Any of those cheap digital scope kits will work just find. If it's not sensitive enough for the microphone, just bring scope back into same room. Put microphone right at speaker.

Play around with it, you'll see what I mean. Pick up a surplus outdoor horn speaker, and see what can be put thru it. Half of playing is scrounging. It's the predator part of play.