I think people would like to know when their laptops are listening. What you guys think?
There are things like Mic-Lock but software could be written to bypass it and use the built-in microphone (still love these though!)
While not a hardware LED you could use Oversight or Micro Snitch  on Mac. Oversight users free, but Micro Snitch comes with Little Snitch. I use Micro Snitch, so I do not have much experience with Oversight, but I love how you can set Micro Snitch to have a floating icon in any corner you choose. This icon would turn on when either your camera or mic is activated. Therefore, you could see when it is turned on. If it gets annoying, you can have it in the menu bar as well.
While it is still a software solution, it’s the best we have. Hopefully one day we can have a microphone LED.
The safest way to disable a microphone is to physically disconnect the microphone, which is offered on some modern devices (hardware kill switches) - but isn’t an option on any device I personally own or have ever owned.
I know of patent pending ways I invented to disable the microphone - but it’s an extremely hard problem to solve. Attempting to isolate/insulate/block the microphone are futile or impractical due to the amount of sound reflecting/absorbing material you would have to attach to your Mic.
Do you think a company could make money selling the intellectual property to externally “kill” a MIC without harming it in our current society? My company doesn’t seem to think so :(
Source? Privacy expert Mark Zuckerberg