Bulding an electronic dog whistle

[The Ghost of General Lee]

Is it feasible to build an electronic dog whistle? I would like to
push a button inside and have the "sound" emanate from a speaker
outside. Of course, I want to confine myself to the frequencies
outside the range of human hearing. Anyone ever pulled this one off?

 

The Ghost of General Lee wrote:

Is it feasible to build an electronic dog whistle? I would like to
push a button inside and have the "sound" emanate from a speaker
outside. Of course, I want to confine myself to the frequencies
outside the range of human hearing. Anyone ever pulled this one off?

Google is your friend:
http://www.mitedu.freeserve.co.uk/Circuits/Misc/whistle.htm