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Dog Repellent Project Circuit

The electronic dog repellent circuit diagram below is a high output ultrasonic transmitter which is primarily intended to act as a dog and cat repeller, which can be used individuals to act as a deterrent against some animals. It should NOT be relied upon as a defence against aggressive dogs but it may help distract them or encourage them to go away and do not consider this as an electronic pest repeller.

The ultrasonic dog repellant uses a standard 555 timer IC1 set up as an oscillator using a single RC network to give a 40 kHz square wave with equal mark/space ratio. This frequency is above the hearing threshold for humans but is known to be irritating frequency for dog and cats.

Related Products: Audio Indicator and Alerts

Since the maximum current that a 555 timer can supply is 200mA an amplifier stage was required so a high-power H-bridge network was devised, formed by 4 transistors TR1 to TR4. A second timer IC2 forms a buffer amplifier that feeds one input of the H-bridge driver, with an inverted waveform to that of IC1 output being fed to the opposite input of the H-bridge.
For more electronic dog repeller circuits check the related links bellow.

Cat and dog repellent circuit diagram

dog repellent circuit schematic

This means that conduction occurs through the complementary pairs of TR1/TR4 and TR2/TR3 on alternate marks and spaces, effectively doubling the voltage across the ultrasonic transducer, LS1. This is optimised to generate a high output at ultrasonic frequencies.

This configuration was tested by decreasing the frequency of the oscillator to an audible level and replacing the ultrasonic transducer with a loudspeaker; the results were astounding. If the dog repellent circuit was fed by a bench power supply rather than a battery that restrict the available current, the output reached 110dB with 4A running through the speaker which is plenty loud enough!

The Dog and Cat repellant was activated using a normal open switch S1 to control the current consumption, but many forms of automatic switching could be used such as pressure sensitive mats, light beams or PIR sensors. Thus it could be utilise as part of a dog or cat deterrent system to help prevent unwanted damage to gardens or flowerbeds, or a battery powered version can be carried for portable use. Consider also using a lead-acid battery if desired, and a single chip version could be built using the 556 dual timer IC to save space and improve battery life.

66 Comments

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  • Colin Mitchell

    Look on eBay for Piezo Tweeter for about $3.00 plus $7.00 postage. The maximum frequency response will be about 30kHz.

    This is the cheapest and best item for the output device.

  • algorithm

    Hello,
    maybe You have an idea, what will be algorithm of dog repellent, Which could be write down on Matlab?
    What is sampling rate?
    How to designed generator (maybe filter in right mode? ) with variable frequency ?
    Thank You

  • Nrreaj Arya

    Dear Sir,
    >
    >
    >
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    >
    > And cover parking area 2000 sq ft.
    >
    >
    >
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    > Kleenair House- Unit – II,
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    > Gat No- 120 to 122, A/p Pirangut,
    >
    > Tal – Mulshi, Dist – Pune – 412411.
    >
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    > Mob- 9766354647.
    >

    • N.C.Sinha

      Could you please send me the circuit diagram of Autp Park rat repeller.

      Thank you.

      N.C.Sinha

  • ceana reyes

    I want to build a dog repeller circuit like this.. can you give me a part number/supplier for the ultrasonic tranducer.

  • karthik

    Hi everyone..!! I have a doubt..
    In my home 4 -5 street dogs have made their permanent residences at the top floor & they pose a serious menace. They come to bark at and bite the one, who comes to shooo it away.. I want to drive them away from my home. Will this circuit be a suitable solution for it? Pl. reply soon …

  • Colin Mitchell

    For a correct version of this circuit, see:
    http://www.talkingelectronics.com/projects/50%20-%20555%20Circuits/50%20-%20555%20Circuits.html

    Dog Bark Stopper

    Colin Mitchell
    TALKING ELECTRONICS.com

    • Colin Mitchell

      Look on eBay for Piezo Tweeter for about $3.00 plus $7.00 postage. The maximum frequency response will be about 30kHz.

  • JED

    Look up H bridge circuits and see if you
    find any with the emitter as the output
    like these. This whole project seems to be
    a bad joke.

  • Jed

    I am not confirming snot, if you want to buy them buy them if not then don’t. Got to help yourself!

  • Jed

    I used the Tip41NPN and Tip42PNP

    • Ananda

      Dear Jed,

      Thanks for the reply but you have not mentioned the results as I wonder the ft of TIP 41 is 3Mhz whereas the BD 131 is >60Mhz. Please confirm before I buy for those Transistors.

      Appreciate very much once again.

      Thanks,

      Ananda

  • Ananda

    Cat and Dog Repellant Circuit

    Dear Sir,

    The transistors BD131-132 are difficult to find and can you help me to find the most suitable equivalent transistors to replace BD131-132.

    Thanks,
    Ananda

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