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Cat owners know that our cohabitants enjoy technology only insofar as it allows them to intake heat and sharpen their weaponry. The infamous Afroman of Afrotech Mods decided to take matters into his own hands and developed this USB-powered ultrasonic cat-repelling device.

The device uses an alarm powered by the computer that emits a 25kHz screech—a tone that cannot be heard by human ears, but is heard by cats—to scares little kitties away. (At least that was the theory.) Unfortunately, the USB powered ultrasonic cat repelling-device put out a faint audible beeping that Afroman wasn't able to fix, and didn't even repel the cat. She was startled for a few seconds, and then got used to it and started playing with it, surely as a precursor to a lazy shredding.


The parts that were used included two 25kHz ultrasonic transducers, a USB cable, a Perf board, an 8-pin chip socket, a PIC12F675-I/P, a 42TL031 600:100 Mini audio transformer, and any capacitor larger than 1uF. He then stripped the USB cable, soldering the chip socket to the board and then connected the USB cable to the filter capacitor start the procedure. So like, don't do that if you try to make one of your own.