DIY data transver alarm for a blind friend. Answered
A good friend of me, who happens to be blind, posted an interesting question on facebook earlyer today, and it got me thinking. He wondered if it would be possible to get alarm feedback from a usb key when a file is done saving. So I was thinking, could I somehow do something with a transistor or a relay on a usb cable, to sound an alarm for 1.5 seconds when the voltage turns to absolute zer0. I know how to solder and i did projects before, but never something like this, with this kind of tech. so tips and feedback could be welcome.