How to turn Smoke alarm into Ultrasonic Dog Repellant

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?

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

Any way of changing the title?

  Joined September 26, 2018      1
Wednesday at 03:18 PM

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



  Joined May 19, 2015      213
Tuesday at 03:45 PM