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How can I make a mosquito repellent??

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HellSpawn

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Hello everybody!Can anybody help me build a mosquito repellent?I want something that can work with batteries and be reletively small.I have searched the Inernet but I haven't found any schematics.Thanks in advance!
 

bogdanfirst

New Member
well basicly the mosquito repelleant is an oscilator wich genertate ultra sounds. i have a study in a book.....wich sais that frequencies around 17-20KHz are effective.
so you can build a 2 transistor multivibrator, or a 555 oscilator and use a piezo buzzer to generate the sound, wich is quite small. the schematics i have are build using old components, Ge transistors, but the idea is that matters.
 

HellSpawn

New Member
I thought about using a 555 as an astable multivibrator but this will give me a square pulse sequense.Will this work or will I need a sin waveform???
 

bogdanfirst

New Member
it will work. the oscilaotrs that i have in the book use square too.
but i talked to other people that build such devices.....and they said they are not too efficent, the 'blood suckers' get used to it. and doesn't bodder them anymore. but it will bodder your cat or dog.
 

Phasor

Member
That's a very standard circuit - but I'm not sure why you've got such a large difference in the value of the capacitors (820p and 3.3u). They should be equal (for 50% duty cycle).
 

Nostrafus

New Member
Well, I myself object to the use of such devices. Please note, none of this is actually based on any real evidence, just something that is quite possible, and all common sense points that this may be true... so take this 1/2 heartedly.

Because they use ultrasound as a method of detering mosquitos, if they become in wide use in certain areas, it may also have the effect of detering other benificial animals such as bats, which use echolocation as their primary means of hunting, and the use of ultrasonic devices can blind a bat from hunting in the range at which the device operates.

If you want a good idea of what something like this can do, take a good look at the movie Daredevil, if you have seen the movie, I believe you'll remember the part where the motorcycle explodes, this effect can be similar to what happens to a bat.

Before constructing one of these, I'd look up what species of bats inhabit your area, and if their primary food is insects, such as is in the case of brown bats, in which a family (hunting group) of 10 can eat up to 1 lb. of mosquitos a night (each weighing under 1/10th of an oz that's 1600 if they ate just mosquitos) I'd suggest looking into building a bat house under your roof.

If mosquitos are that much of a problem, suggest that your neighbors do the same. And come this time next year, you won't have a mosquito problem anymore.
 

HellSpawn

New Member
I think that you have misunderstood the whole idea.I am from Crete and when going out for a coffee at some place near the sea mosquitos can be a real problem.I am not trying to build an ultrasonic "warhead" of some kind that will disturb nature's balance,just something that will create sort of a protective bubble around a person so that he or she won't get stung.My girlfriend is allergic to the various lotions and stuff against mosquitos so I trying to make her that.Thank you all for your help. :D
 

HellSpawn

New Member
Just one last question.The circuit provided by dreamie works at what frequency?I think that a frequency of about 20kHz and above is required to repel mosquitos.Will that work?Does anybody have a different idea or improvement for that circuit?
 

fat-tony

Member
HellSpawn said:
I am not trying to build an ultrasonic "warhead" of some kind that will disturb nature's balance,just something that will create sort of a protective bubble around a person so that he or she won't get stung.
I'm not sure why, but that makes me smile a lot :D
 

Sarac

New Member
i've read somewhere that only female mosquitos are bite and THEY ARE DEAF. So sound emitting circuits will not work on mosquitos.. :wink:
 

HellSpawn

New Member
Indeed it is the females that feed on blood.Male mosquitos feed on fruit juice.(Any resemblance to human females is completely coincedential :lol: )
They are not deaf,as a matter of fact the sound emitting circuits actually reproduce tha sound of male mosquitos.Seems that female mosquitos avoid the male ones unless it is reproduction time.
And you are right my friend it was a funny answer.I laughed too once I saw it written..... 8)
 

giftiger_wunsch

New Member
the 'blood suckers' get used to it. and doesn't bodder them anymore.
If the sound no longer bothers them, maybe it wold improve its effectiveness to periodically change the frequency of the sound within the effective range.

Even if the mosquitos are deaf to sound, it's possible that they may be discouraged because they can 'feel' the sound. Don't forget that a 9V battery can cause a piezo transducer to create quite a loud sound, and the high amplitude combined with an effective frequency may disturb a mosquito's flight or give it a good shake about!
 
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giftiger_wunsch

New Member
Whoops, so it is. The current mosquitos' distant ancestors remembered the time when they were foiled by a supernatural high-pitched sound, but to the current generation, it is just an ancient legend and the food supply is plentiful. :D
 
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