DFRobot Gravity Expansion Shield and Sensors for Arduino - DFRobot SEN0232, This Arduino compatible sound level meter (also known as a decibel meter or noise meter) uses sensitive circuitry and a low-noise microphone to enable it to accurately measure the sound level of the surrounding environment. It can be used for environmental noise testing, such as a highway noise monitoring station, bedroom noise monitoring, etc. Nowadays, there are many kinds of sounds surrounding us, some of which are very loud. It is essential to measure whether the sound is noisy enough to do damage to our health.This sound level meter is compatible with Arduino and is plug-and-play with no soldering required. It supports 3.3 to 5.0V input voltage, 0.6 to 2.6V voltage output. The decibel value is linear with the output voltage, which gives a simple conversion, without complex algorithms. DFRobot SEN0232 Gravity: Analog Sound Level Meter