The Sound Level-Meter is an enhancement on the universal gauge from the previous tutorial. The difference with this device is the introduction of sensors to the system. This tutorial uses the AX-S1 sensor module to sense the volume of the surrounding environment and then actuate the servo motor in response to the noise levels experienced by the sensors.
This is another simple tutorial which is very easy to put together. It introduces the user to the sensor module and gives an example of how it can be used to allow a device to interact with it's environment.