Turn off at the OS level unless you're actively using it, or use a headset with a hardware switch/detachable mic.
You can buy some cheap 3.5mm earphones, cut the wire right in the beginning, and plug it into your microphone slot, and assign that as your mic. If you're on mobile, it'll automatically do it. Basically piping from /dev/null
>> Basically piping from /dev/null
Can you actually do that?
Why not piping from /dev/zero , heck even /dev/random or /dev/urandom ?
yeah, i guess it's incorrect, and probably would be something like /dev/zero
hmm. when reading, /dev/null behaves like an empty file but /dev/zero gives you endless amounts of NUL bytes ('\0') ; iirc and the /dev/random and /dev/urandom gives you endless amounts of random bytes, but there is a subtle difference between those random sources.
There's an amazing little utility called MicroSnitch from the guys who built Little Snitch. It actually shows screen overlays when something starts using microphone or camera.