Sorry, this is absolutely not a thing. You’d have something if you said that someone could use the speaker as a mic, although of course you can’t do that on a p

Sorry, this is absolutely not a thing. You’d have something if you said that someone could use the speaker as a mic, although of course you can’t do that on a phone without taking it apart. But the accelerometer on a phone, while in the phone, cannot be used as a microphone. I’d be very very impressed if someone managed to get usable sound out of an accelerometer floating in free space even, although that’s mildly conceivable. And while I hate to appeal to authority, I worked at Fitbit for 7 years and was directly responsible for the algorithms team that built the step counting, activity recognition and other algorithms for a chunk of that time. I’m very familiar with what the data off an accelerometer looks like and what you can train a model to extract from it.