Comment by TeMPOraL
6 years ago
Not annoy, but learn more about them. The original idea of investigating ultrasound environment came to me when I was taking care of some rats for a few weeks for a friend; I read a short book on them, from which I've learned that they communicate with ultrasound, which made me want to "listen in" on that communication, and perhaps replay some of it.
FWIW, I have a cat myself, and I'm not the kind of person to annoy animals on purpose.
I'm not very good with electronics, but someone who is showed me this cool device they built themselves. It was something like a "frequency-lowerer" (NO idea how that works, I know DSP but not the analog stuff) and the intended use was to be able to hear the screeches of bats. One way to test it was to jingle a bunch of keys in front of its mic, the metal clanging has a lot of ultrasound.
I dunno how hard they are to build (that guy was pretty skilled), but I think you can also just buy these devices ready made. Probably called "bat detectors" or something.