DFRobot Gravity Analog Sound Level/decibel/noise Meter 3.3~5V Compatible with arduino for environmental noise testing/monitoring|noise meter|noise decibel meterdecibel level meter - AliExpress
Arduino sound sensor noise level detector example - Pat Howe's Blog
Arduino Sound Level Meter
How to get correct output of sound level meter in db - Project Guidance - Arduino Forum
Decibel Meter using Sound Module & Arduino with LCD Display