How to turn Smoke alarm into Ultrasonic Dog Repellant

Sam Carleton's picture

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Joined: Sep 26, 2018

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How to turn Smoke alarm into Ultrasonic Dog Repellant
September 26, 2018 - 3:24pm

I am pretty new to all that stuff. 

So far I have experimented with 555 at 10-25 kHz, but the dB is too low. Even at 10 kHz the output power is pretty low (measured by my Samsung app, Oscope at  2-4 cm distance  it's just a few dB). I am using a piezo transducer from an old sound system, no spec, just a piezo disk 2.5cm diam with two leads black and red).

My question : Is it possible to turn an old smoke alarm into an Ultrasonic Dog Replant?

Sam Carleton's picture

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Joined: Sep 26, 2018

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Apologizes for the typo  - it
September 26, 2018 - 3:37pm

Apologizes for the typo  - it's  Dog  REPELLANT, Dog Silencer

Any way of changing the title?

Jayant's picture

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Joined: May 19, 2015

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Animal Repellent Circuit
September 26, 2018 - 5:51pm

You should archive a frequency of min 20kHz to get into the ultrasonic sound regin which we humans cannot hear but other animals like dog can hear it.

Your approach is also correct, just use a 555 timer to produce high frequency signal and connect it to a buzzer, what problem are you facing? share the circuit.

What do you mean by output power is very low? are you trying to driver a bigger speaker ?

Also check out this article where a similar one is built

https://circuitdigest.com/electronic-circuits/mosquito-repellent-circuit