"Smart" devices are all around us nowadays and many of them have built-in mics which can be be misused to spy on you in cases when the device is hacked (which is rather probable to happen as there are countless and growing vulnerabilities in all the software and hardware and botnets grow and flourish).
The question is how to find all the mics to take care of them a way or another?
Laptops and phones are the obvious hits. Smart TVs, set-top-boxes and game consoles, different kinds of video cameras etc may contain tiny built-in mics with (if that is a visibly advertised feature) or without you knowing.
Is there a way to find them all? E.g. by detecting magnets or something...