Don't know exactly where I should post this but I'm pretty sure it would be fine here . I was walking home right now late a t night and I walked by this persons house and out of no where I heard a click and a really high pitched sound that made my ears ring suddenly came on then I kept walking and what I assume was the end of his house another time that high pitched sound came on . Is this a motion sensor of sorts or am I going nuts? I didn't walk back to see or try it again cuz it creeped me out I was wondering if there was motion sensors like this or is it something else. Thanks for reading.
The latest craze, since they are legal most everywhere, is ultra-sound animal repellents. If it hurt your ears, imagine what a dog or cat feels. Farmers and those with a lot of land can legally buy pain field generators, much like the military uses.
It is 100 to 2,000 watts of ultrasonic waves. They are triggered by motion or sound and MUST shut off after a few seconds. The local police can intervene if it runs non-stop and the neighbors complain. The sound can travel 300 yards even in residential areas, and can be heard through glass windows.
Some offer options like a 'bark' detector for noisy dogs, and bright flashing LED's that cats hate.