Dog Repellers

I find a boot quite effective!

Since dogs hear up to 20 kHz and beyond, while we cannothear beyond about 18 kHz, one wants to send sound out at some frequency between perhaps 18 kHz and 25 kHz, maybe hgher; depends on the dog breed (no known data) and distances invlved. If it is beyond 100' (30m), the higher frequencies may not propagate well.

Any piezelectric "beeper" can be driven at these high frequencies to produce useable sound. At those ultrasound frequencies, it must be used like a flashlight (torch), directing it at the area intended to be insonified.

Build an oscillator to run at theat frequency, then drive the piezoelectrin by capacitively coupling it (.01 uf for instance) to the oscillator output.

Obtain two such beeper elements; one to dive, the outher to receive so you can trace what you are doing, find beamwidths, etc.

The reciver is just attached to the input of a braodband audio amplifier, and either present its outpot on an oscilloscope, or rectify it to hear your raspy envelope while developing this repeller prototype.

As to the frequency and envelope; you will have to experiment... a raspy envelope (we call it "the rasberry") (pulsed at 10-50/sec for instance) might discourage the dogs from the area. Ther are ther schemes, I am sure, subject to invention.

As to the frequency, it's hard to determine... Best to build a battery powered hand-held unit prototype, and carry it about the neighborhood, and flash a few mutts, to determine their reaction, and adjust the frequecy and the rasberry to suit.

Good luck

Angleo Campanella