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.


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  • Patricia

    Is there any device on the market that can pick up and read the use of these ultra sonic dog deterrents. I live very rural 100 ac farm is at the end of a spread out ranch community , having theft, trespassing, vandalism trouble, not to mention finding a pile of cigarette butts right at my main gate. and my past dog going crazy in the house at the windows about 10 minutes after turning off my lights in the house to go to bed those dogs are now dead. installed a 6ft metal bar panel fence since I live alone and Husband is in Afghanistan and acquired some very good dogs All activity stopped for the last year. Then I noticed vehicles pulling up to my main gate and point something at my dog and he just went confused and wondered dazed back to the house and the vehicle drove away, then again with a vehicle driving off the road stopping at my fence and again pointing something that looked like a small yellow spot light again my dog was confused and started walking away and the vehicle drove away. I filed an animal cruelty report, coming to my property to bait and assault a dog in their own yard. But I need some sort of proof that a device is being used to break the dogs from alerting to threats around my house. Especially at night when it’s too dark to see anything 10ft in front of you. Thank you for any direction you can offer .

  • Tom Keegan

    Is there one of these available to deter bovine animals, I’m a farmer and have been attacked, I’m lucky to be alive, some people have been killed by cows post calving, and by bulls.
    This is a very IMPORTANT issue, please help me out here.

    Tom, the lucky one….so far.

  • Harry Layne BSc.

    HELGA….Although a touch expensive for your size of space…Try sprinkling PEPPER on the lawn etc as this has been proven to work in the past. You have to repeat the process when there is a strong wind, but dogs do not like sniffing PEPPER or even CURRY POWDER, as it makes them sneeze and they will soon leave the area and find somewhere else to do their business, Good Luck, Regards HL.

  • Ultrasound

    The elderly in particular use a cat-deterrent in their garden. It is a small apparatus with a speaker attached to it. It produces a high-pitched bleep of more than a 100 decibel. The sound is mostly only audible for children, youngsters and people with ears that are still good. Many cat-deterrents use the same noise as the Mosquito. The sound causes pain in the ears, headache, and ringing in the ears. If you have any complaints consult your GP and make mention of it on social media!

    Working Mosquito: 17KHz-20KHz 90dB
    Woring Cat Deterrent/Animal Chaser: 16KHz-23KHz 130dB

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    Where is your website?

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  • John

    This circuit is incorrect and will not work as drawn. For a start, the output of both 555 timers are connected together, and the transistors on the right side are being ‘driven’ by one of the 555 timer inputs.

  • Mircea

    This project made me remember when I first bought one of this dog repellent devices. Let me share you some of my experiences.
    I have noticed that puppies a few month old and young dogs can hear the sound and get scared easily, but new borned and old ones cannot hear the ultrasonic frequency. Also, some dogs become more aggressive. Cats can hear it too but most of them are not scared by the sound, probably because it’s not an annoying frequency.

  • coetzer

    I built it & it didn’t work. then I noticed the same thing; output of IC2 is no.3 should go to base of TR2 & TR4 so I switched # 3 & #2 on IC2. I tested with 5, 12 & 17 voltDC power supplies. TR2 overheats with 12 volts, TR 1, 3 7 4 remain cool. AC output voltage of IC1 was 7.7 volts. AC output of IC2 was 9.7VAC
    Meanwhile squirrels came & ate most of my red currents. I was going to use it to repel them

  • yanus

    wat is da exact ic dat i ned 2 use 4 dis circuit???

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