Ultrasonic rodent repelllant

[ardhuru]

My car suddenly developed multiple problems overnight. The battery wouldnt charge, the power steering didnt work and the AC compressor wasnt operating. At the garage, it was found a rodent had chewed up a couple of wires, and a belt. I had had a similar thing happen to my earlier car as well, and the car's electrical system was never the same again, after the 'repairs'. Therefore, this is one thing that I'm morbidly scared of.

So, I plan to build an ultrasonic repellent, and would like some insight towards the design. The unit would be mounted under the hood, and would blast out a burst of ultrasonic sound every few minutes;

Now for my queries; Is there a specific frequency that is most effective? Would it be smarter to use a few different frequencies, at random? Would the standard ultrasonic transducers (as used in distance measurements) be able to handle anything other (lower) than the specified frequency, usually 40 KHz? And what is a good, yet safe amplitude for the sound burst signal going to the transducer?

Lastly, does it make sense at all? Or is there a better solution?

Regards,

Anand

[Acetronics2]

Hi, Anand

15 Years ago, I built a similar device using a Motorola Piezo Tweeter able to pass 40 kHz ( the rectangular shape one ) 100 W ...

but cheap !!!

http://www.adelcom.net/MOTOROLA_ksn1016a.htm

Do not laugh . you need some power for the device to be really effective ( say using a 12v bridged amplifier i.e.)

Some frequency shift between 25 and 40 Khz ( randomly is best ...) will be the must ...

But remember gentle Bats will leave the vicinity ...:o

Alain

[rsocor01]

Lastly, does it make sense at all? Or is there a better solution?

Regards,

Anand

Yes, there is a better solution. Get a cat !! :)

I looked at a few articles about Ultrasonic Pest Control and it looks like the effectiveness of this method is still not clear.

http://en.wikipedia.org/wiki/Electronic_pest_control
http://www.victorpest.com/advice/all-about/victor-repellents/types-of-repellents

[ardhuru]

Hi Alain,

Thanks so much for sharing your experience. Before I started this thread, I too did some reasearch on this and as rsocor01 says got some very conflicting opinions. Which is why I am curious to know, did the system work effectively? With your design, did the problem get solved?

Of the units being marketed, I notice a lot (most?) seem to use a wimpy piezo disc as a transducer. I'm sure these cannot handle either the power, or the frequencies that would be required. Perhaps, these are also responsible in giving a bad name to the product as a whole category.

But, with a better designed (and more powerful, as the one you describe)) unit I dont see how it *cannot* work? Especially in the small environs of a vehicle engine compartment; I mean, imagine being blasted by a loud sound every few minutes; wouldnt the chaps prefer to take up residence in a quieter car?

BTW, Alain, was your unit designed to work in a car as well? How often did you have the bursts, and how did it affect the battery? I ask because there are times when I am away, and its not unusual for the car not to be used for days at a stretch.

Regards,

Anand

[zipwize]

We had mice often. My wife bought a box of these and installed them all over the house and garage. She didn't tell me. I had a headache. The dog was restless. I woke up and went around the house discovering and pulling these out of the outlets so I could sleep. I found each one by the sound.

My wife got mad at me for disconnecting them and said I just pulled them to make her mad.
She said she couldn't hear them and that I couldn't possibly hear them either.

So how did I find them all? (dear).

I left the one's in the garage as I think they work. I see no mouse droppings since they were installed.

[Ioannis]

Hmm, thats interesting. Can you make a reverse engineering and lets know wat frequency, sweep maybe it is working, what does it have for speaker, how much power it is outputing, what power supply it has.

I think it must be lower at frequency of the 19-20KHz limit. Otherwise it is not possible to hear it or make you feel something or worse have a headache. May there is the secret. Make it close to the limit of human hearing point.

Ioannis

[Acetronics2]

Hi, Anand,

Yes, it has been working fine ( was in a garage ) ... no beasts nor pets around for a while !!! ;)

but sure it gives Headaches if you're not protected yourself ...

this is very well known in Africa where Europeans use their HiFi equipment as the final amplifier !!!

But think when you will stop it ... they'll be back after a moment.

so, poisonning or gunning rats ( my .22 cal. rifle works fine for that ...) is THE solution ...

Also think those beasts come when they smell something to eat ... and have somewhere to sleep.

Alain

[ardhuru]

Hi Alain,

Thanks for the confirmation that it works. This, alongwith your earlier pointers for the design is exactly what I was waiting for before I start building.

Hopefully, this should be the last time I've suffered this...

Regards,

Anand

[ardhuru]

For whatever its worth, I came across an almost identical thread started by somebody else on another forum. One of the posts pointed to this: http://www.ratbehavior.org/rathearing.htm and the general consensus was it wasnt going to be effective.

Any observations?

Anand

[rsocor01]

For whatever its worth, I came across an almost identical thread started by somebody else on another forum. One of the posts pointed to this: http://www.ratbehavior.org/rathearing.htm and the general consensus was it wasnt going to be effective.

Any observations?

Anand

Hmmm, definitely this article is not helping you at all. But, if you are so eager to work on this project just give it a try. Experiment with diferent frequencies and see what happens. Maybe if you try to duplicate a predator's ultrasonic sound it would work. Just a thought.

Robert