Amplifier for frequency generator

What's electronic repellent? Doesn't sound like something we want on SEB. :^)

Nothing special.

Well you need some spec's... Freq is 0-4 M Hz. What's the voltage gain, and max output current? There are an awful lot of opamp's out there.

George H.

"Goran"

There is only one "device" that can reliably rid your premises of mice, rats and cockroaches - and that device is known as a cat.

... Phi

------------------ Cat is good solution ( i have 2 ) but this project is more aimed on insects :-)

There are bunch of them on the mark but my project is more on the research side and nothing of this will go commercial.

Freq is 0-4 M Hz. What's the voltage gain, and max output current?

- I was thinking of 3V.

- the device should work in 1-2 meter range so i will need relativly small current.

- main frequency range will be from 1khz - 60 khz and 300 - 400 khz

But you'll be also hurting your pets ears..

Jamie

Like i wrote, it for testing purposes and no animal will be near this :-)

Do you have some schematics or link on some amplifier ?

rats

do

Sorry I'm still confused. Are you broad casting the frequencies into the a ir with an antenna? Or turning it into sound waves? If it's sound then wh at's the transducer? There are ultra sonic piezo transducers, but I don't think they couple to air very well. (big impedance mismatch.)

George H.

Digikey has quite a few opamps (~33k)

George H.

One word of warning: choose your cat carefully. My brother's cats are good hunters -- they catch mice, chipmunks, and voles -- but then they bring their prey inside, still alive, and release it to play with later. ( Or not, if they get distracted. )

Voles and chipmunks, even half-dead ones, are _fast_ little critters.

Frank McKenney

-- There is a wistful myth that if only we had enough money to spend-- the figure is usually put at a hundred billion dollars--we could wipe out all slums in ten years, reverse decay in the great, dull, gray belts that were yesterday's and day-before-yesterday's suburbs, anchor the wandering middle class and its wandering tax money, and perhaps even solve the traffic problem.

But look what we have built with the first several billions: Low-income projects that become worse centers of delinquency, candalism and general social hopelessness than the slums they were supposed to replace. Middle-income housing projects which are truly marvels of dullness and regimentation, sealed against any buoyancy or vitality of city life. Luxury housing projects that mitigate their inanity, or try to, with a vapid vulgarity. Cultural centers that are unable to support a good bookstore. Civic centers that are avoided by everyone but bums, who have fewer choices of loitering places than others. Commercial centers that are lack-luster imitations of standardized suburban chain-store shopping. Promenades that go from no place to nowhere and have no promenaders. Expressways that eviscerate great cities. This is not the rebuilding of cities. This is the sacking of cities.

-- Jane Jacobs, "The Death and Life of Great American Cities"

-- Frank McKenney, McKenney Associates Richmond, Virginia / (804) 320-4887 Munged E-mail: frank uscore mckenney aatt mindspring ddoott com

That only does a 100ma output but you can hang a totem pole off it.

Jamie

Yep. One of my cats brought in a field mouse, played with it for some time, then it got away and hid in our pantry. Fortunately these mice are quite curious... everytime I'd open the pantry door, he peek out from behind stuff on the shelves, then disappear.

So I hooked up the central vac... I'd open the pantry door... when I saw him it was just poke the hose at him.... burble, burble, burble, clunk, clunk, clunk thru the turns... dead at the bin >:-} ...Jim Thompson

Sorry I'm still confused. Are you broad casting the frequencies into the air with an antenna?

Or turning it into sound waves?

If it's sound then what's the transducer? There are ultra sonic piezo transducers, but I don't think they couple to air very well.

----------------------------------- Hi George !

For 30 - 60 khz i will use ultrasonic piezo. But for other frequency ranges i was planning to use antenna with gain control.

I have made one simple project with ultrasonic piezo and it worked quite good. But this project has fixed frequency. Now i have to test few different frequency ranges so this could be a problem.

I'd forget the antenna and E&M radiation. That's not going to do anything, unless you get enough power to 'cook' the critter.. and then the FCC might object..

You might start by finding our what frequencies the various critters can hear. I'd bet some biologists have already done this.

George H.

Chipmunk fleas can jump ten feet :-)

Around Subway Cave, adjacent Lassen Volcanic National Park, in Northern CA, there are official notices regarding chipmunk fleas carrying bubonic plague.

Get an improved cat then:^) One of my cats kills every darn critter entering the house, no matter how small it is. Sometimes I see him fighting like against invisible ninjas, only to find seconds later a small dead mosquito/fly/spider whatever nearby.

Won't work. Either it's too weak to work as a repellent for insects or it is going to be very annoying if not harmful pets/humans too.