What component would I need to use to display the noise level(decibel level) of a surrounding.I have a project to display the decibel level of a a surrounding on a 7 segment display.What sensor would i need to use to capture the decibel level.Will a mic do?If so ,what kind a mic do you recommend.
The easiest thing to use is the Sparkfun Microphone Breakout board (https://www.sparkfun.com/products/9964). Or, use the schematic for that board as a starting-point for your own design.
Electret mics have to be powered. You need a preamp to bring the millivolt microphone signal up to a level that can be read by the Arduino. And, since the Arduino can be damaged by the negative half of an AC audio signal, the Arduino's input needs to be biased. That breakout board handles all of those issues. The only thing it's missing is variable gain.
NOTE - Any time you make an SPL meter, you'll need a known-good SPL meter to calibrate it.... We generally don't know the sensitivity of the mic and even if the sensitivity is published there is a few dB of tolerance. And, it depends on if you are reading the peaks or averaging and the "weighting" of the measurement, etc. And, every "real" SPL meter is calibrated with a known loudness, and that's just how it's done.