>>mannan+y6
From a hardware point of view I've also noticed that speakers work like poor microphones (and LEDs like poor solar panels / light sensors), but is there any way to actually make this work on most devices without physically changing wiring? If the circuits aren't made to take measurements (or the software can't get at the readings) but only set a voltage on the wires, there wouldn't be a way to (ab)use this. I don't know enough about electronics to know whether this is commonly the case
Not that it's not a good thing to be aware of, but do you have any sort of source for what kinds of devices can have their speakers turned into microphones? Then I'll believe you about the government part