App that accesses microphone

Is there a way to access the microphone on the phone for an app?

What I am looking to do is create a noise level meter for emergency situations. Ideally the app would access the microphone, analyze the noise level and report a peak value. The value would then be compared to a threshold value and report if the value exceeds the threshold.


Only in the construct of a call that’s up. You can’t access the mic otherwise. So, fire up a call, then have the connected system perform the audio level analysis.