Is there a something that can detect audio for the app inventor.

So what I am trying to build is something like a time counter. 

I wish to trigger the clock by a sound. The moment a sound is made the app starts the stopwatch and logs the timing of the next two sounds.

In order to do that I need a sensor for audio/sound which I can't find in the AI. Can anyone help me a hack for the same?

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The bigger problem you have is that App Inventor cannot run in the background, so unless you want to have your app active all the time, this is a showstopper. And, indeed I think there is no component that will pick up sound by itself.

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The moment a sound is made the app starts the stopwatch and logs the timing of the next two sounds.

you might be able to do this using the Sound Analysis extension from Mouhamadou

MIT App Inventor Extensions

Multimedia component that analyzes the pitch of a sound through the microphone and returns it. It can be used as an input to different situations, for instance to control some components with a specific sound whistle(pitch > 500Hz) or clap(pitch > 2000Hz).        

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