Cat and Dog Repellent Circuit Diagram

august 23, 2012 by team elprocus 

The electronic dog repellent circuit diagram below is a high output ultrasonic transmitter which is primarily intended to act as a dog and cat repellent. 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.

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 which can be seen at A & B in an oscilloscope.

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With this cool cat/dog repeller circuit you could chase the cats  off  from any where you want. In fact, I designed this circuit to chase my cat from my computer table. Most of the animals like cats respond violently to ultrasonic sound and in fact it’s the best way to chase them off. This principle is employed in this circuit.

The circuit here is nothing but an astable multivibrator wired around NE555 (IC1). The cat repellent circuit produces an ultrasonic sound in the range 15-20Khz. The NE 555 is enough to drive a small piezo buzzer and no amplification stages are needed. The POT R2 can be used to adjust the frequency of sound.

Cat Repeller Circuit diagram with Parts list. 

Notes.

• The circuit can be powered from a 9V battery or the power can be tapped from your computer SMPS.
• The circuit can be assembled  on a general purpose PCB.

Authors view. 

I do not guarantee the full effectiveness of the circuit.You have try a lot of frequency settings to make your cat feel discomfort at last. More over the cat may get accustomed to the sound after some time. For me the circuit was only a partial success  and now my cat feels nothing even if the speaker is placed in it’s ear.You try your luck. Best of luck.