The Gravity Analog Sound Level Meter (also known as the decibel meter, noise meter) is a basic noise measurement instrument. This sound level meter is compatible with Arduino. It can accurately measure the sound level of the surrounding environment. This product uses an instrument circuit and a low noise microphone. It supports a wide input voltage of 3.3~5.0V and a voltage output of 0.6~2.6V.
The decibel value is linear with the output voltage, which leads to a simple conversion, without complex algorithm. Sound level meter is widely used in environmental noise detection, such as highway noise monitoring station, room noise monitoring and so on.
The widely available much simpler boards containing just the small electret mics used in this device, with an amplifier, are good for little more than listening for a loud noise against a quieter background. This device gives a reasonable approximation to sound measured in decibels and it's trivially easy to use because of its analog voltage output that's linearly related to sound in units of dBA. If you really want to monitor sound levels with Arduinos, this is the way to do it.