Ultrasonic Pest Repellent

[blueroomelectronics]

Post the power saving circuit.

 

[zeitcheist]

@audioguru, Boncuk

I have an adaptor that converts 220V to 12V. The gadget tells that its output is 12V, 500mA. What does that mean? 500mA output to components? Or maximum of 500mA current that can be supplied? Thanks!

 

[Hero999]

500mA means it can supply a maximum of up to 0.5A (half an Amp), don't worry as long as your circuit uses less than the current rating, it'll be all right - components only use as much current as they need.

 

[zhensheng87]

May I know whether this project is really works or not? Since I am currently doing this project too, is there any tweeter or transducer that can play an ultrasonic sound?

 

[audioguru]

Many articles in Google say an ultrasonic pest repellent does not work.
It might scare away some cats.

The old piezo tweeter used on guitar speakers has an erratic frequency response that drops above 18kHz but still has some output at its rated 27kHz.

 

[mramos1]

Old post,

I bought one years ago. Do not recall if it was 14KHz or 40KHz. The documentation said it made the sound of a dragon fly wings and whould keep mosquitos away. Bought it back when I used to fresh water fish. I agree with Google. They do "not" work, or I just had brave bug where I went. Original listerine does not work either if you read that on the net.

 

[audioguru]

Do not recall if it was 14KHz or 40KHz.

14khz is very audible and annoying if you are not deaf. Nobody can hear 40kHz.

 

[deepak george]

hey i suggest you drop this project...ultrasonic bug repellers have been around for a long time n only a few of them actually work....iv tried a variety of circuits..even calibrated the freqs exactly. and used high freq piezo transducers. All of them are of little or no use at all in driving the pests away...

cheers

 

[mramos1]

Well, I recall as a young tech, I could hear like a 15KHz in the TVs. So it must have been 40KHz on that one I had.

No matter. It does not work.

 

[audioguru]

TVs are not supposed to emit 15kHz. Some parts that are loose do.
A pest repeller is supposed to emit as loud a high frequency as is possible.
A huge difference.

 

[zhensheng87]

Thank u guys for the informations and guides, actually I had also gone through those article saying that this product doesn't works, unfortunately I had chosen this project as my final year project, so is there any suggestion so that I can make a little bit effort to improve this project, btw, I am currently using this circuit(as attached) which i found on google, now I am trying to calibrate 10 different frequencies on the CD 4017 IC (as what deepak george did), hopefully some of the frequency really works to repel any pest or rodent....

**broken link removed**

 

[audioguru]

The CA3130 opamp in that very old circuit is not made anymore.

Are you allowed to simply copy the circuit designed by somebody else for your final year project? Aren't you supposed to design your own project?

 

[mramos1]

TVs are not supposed to emit 15kHz. Some parts that are loose do.
A pest repeller is supposed to emit as loud a high frequency as is possible.
A huge difference.

I was able to here the flyback in the units many years ago. 12-15K range probably, I would guess. But as a kid, I could here it.

Sure I will not here it from the 60" HDTV now.

 

[audioguru]

People who are deaf and old people cannot hear frequencies above 8kHz.
A hearing test does not measure above only 8kHz.

Old picture tube TVs used a high power high voltage horizontal frequency of 15,750Hz but new TVs are different.

 

[zhensheng87]

The CA3130 opamp in that very old circuit is not made anymore.

Are you allowed to simply copy the circuit designed by somebody else for your final year project? Aren't you supposed to design your own project?

Of course I am not going to copy the whole thing, just a reference for me in the project, so any other op-amp like UA741 will do for the op-amp replacement right? Is there any other implementation or features I can add in for the project? Thank You in advance

 

[audioguru]

A 741 opamp is 42 years old. It was designed to amplify DC and low frequencies. Its output cannot have a full swing above only 9kHz.
At 30kHz its output has a max swing of only 8V p-p. At 30kHz its max voltage gain is only 15.

Use an audio opamp like a TL071 that has full output to 100kHz and at 30kHz has a max voltage gain of 100.

 

[mneary]

A 741 opamp is 42 years old. It was designed to amplify DC and low frequencies. Its output cannot have a full swing above only 9kHz.
At 30kHz its output has a max swing of only 8V p-p. At 30kHz its max voltage gain is only 15.

Use an audio opamp like a TL071 that has full output to 100kHz and at 30kHz has a max voltage gain of 100.

The op amp in this project is being used as an oscillator at 2 Hz. A 741, as ugly as it is, should work just fine.

The new squeaky clean TL071 suffers from phase inversion if you exceed its common mode range. This defect rears its ugly head in circuits like this.

 

[audioguru]

The op amp in this project is being used as an oscillator at 2 Hz. A 741, as ugly as it is, should work just fine.

Yes of course.
The opamp oscillator slowly steps the frequencies of the 555 high frequency oscillator.

I wonder if you set the frequencies to play "Mary had a little lamb" over and over and over and over and over and over and ... them maybe it will drive away a pest.
Or maybe if you made it loud enough.

 

[WikiNinja]

Did you ever build it?

I am trying to build this same circuit for a science project. Did you ever build it? Did it work? What piezo did you use?
Thanks for your help.

 

[WikiNinja]

Hi

I was just wondering what are you trying to repel?