making mosquito high frequency to repel

i will send a sch to do and change the capacitor to set right value to your frequency to block out mosquitos

i will send a sch to do and change the capacitor to set right value to your frequency to block out mosquitos

This has been a fun thread. Generally it's accepted that mostquitos are not repelled by high frequencies, however at enough sound pressure you could no doubt damage them! :-) That said, there are lots of fun things you can do an ultrasonic speaker, and a system for generating various frequencies. (and it does annoy dogs so be ready for them to 'sing along' :-) One of my favorites is to take two ultrasonic speakers and have them emit a sinusoid at the same frequency (say 30kHz to be safely out of most people's hearing). Then set them up in a room pointing at different walls. This will create a bunch of standing waves where the sounds overlap.

Now frequency modulate one the speakers with a recognizable audio signal and walk around the room. What you will hear are pockets where the audio is very clear and seems to "spring" right out of the air. Its very creepy and great for a seance party. Other fun things you can do are create air cavities in a 2-liter bottle and set them on a counter, modulate the frequency until you find the resonant frequency of the bottle cavity. Great fun to watch the bottles jump around.

Needless to say, you will be having so much fun you will forget all about the mosquitos.

Chuck

That frequency modulating seems to be the method used for the range of speakers that are highly directional.

http://www.holosonics.com/ is one of a few around.

Must remember this trick for another day.

Thanks

Mark

So as any one confirmed or otherwise the fact that our insect friends are discouraged by the ultrasound?

To be hoest I'm not even sure about the rodents, I know that Dogs don't like it and do start barking which isn't what you realy want I'm sure.:)

John

I think the article that was linked to tended to suggest that they weren't discouraged.

However there are some that still think there is something the tests missed ....

Of course the spray companies would love to continue selling, so anything that is a one time purchase is not in their interest.

Rodents are probably like Dogs and Cats especially since they do use hearing to good effect and have similar ear structures (on the outside anyway), and are likely to NOT like ultrasonics.

If anyone thinks I'm wrong about mosquitoes and hearing, please send me a picture showing those large ears that are able to be turned ....

Not that we have mosquito issues, but we use one of the feramone auto sprayers to keep the smaller flies outside, and that works well.

mark

Thinking about it I remember ones that DX.com sold that claimed to work because they sounded similar to the male mosquito and this kept others away.

To be honest this circuit is so simple then you would be best not to belive any one but to try it out..

It would make a good project and video

How about going to Pat Kelly's page and putting an idea on this now very long LPC800 thread

http://www.element14.com/community/docs/DOC-54622#comment-24214

Get a free dev board from them and put the amp and speaker on it. You can easily vary and experiment withe the output frequencies with your free Swag !!

Vive over engineering!!

We need to find the frequency that affects the insect ???     Is there a range that relates to bugs?  

To get anywhere with this you will need to do some serious research:

Try this for starters:

http://www.ksre.ksu.edu/grsc_subi/Research/archives/2001_ESA_Meeting_Posters/contents/SCJ%20talk.pdf

There is a lot of research material on the web  - you could do worse than read this article and replicate their experimental noise maker. They do not discuss mosquitos but they do give some information about which types of insect might be most affected.

It certainly seems that most of the device on the market are not effective but that for some species effective devices might be possible.

MK