Search for Bird repeller circuit...

mohsen 2012 said:

hello , i want a good circuit of ultrasonic bird and pest repeller like the shown in the video :


I found this circuit but i am not sure if work good or no :

View attachment 112806

Any one have experience please help me....

Thanks

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I am not sure how to repel birds by ultrasound. You can find commercial offers promising some effect. Most birds dislike hanged CDs that generate light flashes, or mockup predatory birds around.

Years ago I was successful with pest repeller, originally made as mosquito repeller. It failed to repel mosquitos (light and wind combination is better) but it does repel mice and moles.
I took a single transistor and with a small transformer I built an oscillator tunable to "above my hearing limit", so > 16 kHz. I used a piezo element from a buzzer, and a 4.5 to 6V battery. These devices operated for several months on one battery, and all users reported a full success with "no mice" in a building.
The schematic is a blocking oscillator,tuning is by a 1 MOhm potentiometer in transistor base line. Select the capacitor in collector LC circuit to get the best output at 16...20kHz from the piezo element.

I heard ordinary sounds about a few kHz in the video. Airports do not use ultrasonic frequencies to shoo away birds, they use gun shots and birds of prey.
Besides, a piezo tweeter barely produces ordinary sounds up to 20kHz, not ultrasonic frequencies, but they claim 27kHz which is a lie.

Audioguru said:

I heard ordinary sounds about a few kHz in the video. Airports do not use ultrasonic frequencies to shoo away birds, they use gun shots and birds of prey.
Besides, a piezo tweeter barely produces ordinary sounds up to 20kHz, not ultrasonic frequencies, but they claim 27kHz which is a lie.

Click to expand...

I agree that the piezo element I used may have a low efficiency but as I heard the sound up to 15 kHz, mice apparently were annoyed enough to leave the building where my device was operating. Also the cost was low, and commercial ultrasonic beepers need more power than one-two milliwatts I used with a success.
I recommend you to try it and see for yourself.

The response of a piezo transducer (like from a beeper) is full of narrow resonant peaks and troughs.