This simple 3 component circuit can be used as a microphone alarm or as a light switch. The way the alarm program works is that it detects changes in sound level and then triggers the light to come on for 5 seconds once the sound level has gone up by 2 or more units.
The light switch works in a similar way except that every time loudness level changes by more than 2 a boolean changes state thus turning the LED on if it was off or off if it was on!
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