Sound levels have many frequencies and the levels are measured in Decibels. The MIKROE VU meter circuit has an LM3914 IC driving 10 LEDs that measure Volts, not Decibels because the LM3915 IC for Decibels is not made anymore. The specs do not say its variation of output level vs frequency.
Maybe you can connect it to one of their computer systems and program it to do what you need.

Yes, I am thinking about using the Mic click — board with SPQ0410HR5H-B silicon microphone | MikroElektronika , which is sampled at maybe at 10ms, I would then take about 15-20 samples and calculate using:
dB = 20 log10 (SPL/reference SPL).

I am thinking about using these examples but use MEMs microphones instead.
Arduino Sound Meter - YouTube

 

1. For noise monitoring you need 12kHz bandwidth (that’s where the low-pass filter is situated in A and C response curves, so you will need to sample at >24kSamples per second, not 100 samples per second.
2. The board has a gain of 44dB, and the microphone has a sensitivity of -42dBV/Pa.
At 1Pa (94dBA) you will have an output of +2dBV. The most that you can have on a 3.3V supply without clipping is 1.3dBV, so your instrument will be useless above 93dB (and that’s assuming signals are sinewaves - allowing for a crest-factor of 6dB limits you to 87dBA)

 

Most microphones distort and compress loud signals unless they are modified to work with loud sounds (in a drum or in a piano).

 

Most microphones distort and compress loud signals unless they are modified to work with loud sounds (in a drum or in a piano).

The data sheet says 10% thd at 115dBA, so that seems to be about 1dB of compression.

 

1. For noise monitoring you need 12kHz bandwidth (that’s where the low-pass filter is situated in A and C response curves, so you will need to sample at >24kSamples per second, not 100 samples per second.
2. The board has a gain of 44dB, and the microphone has a sensitivity of -42dBV/Pa.
At 1Pa (94dBA) you will have an output of +2dBV. The most that you can have on a 3.3V supply without clipping is 1.3dBV, so your instrument will be useless above 93dB (and that’s assuming signals are sinewaves - allowing for a crest-factor of 6dB limits you to 87dBA)

So how do they do it on mobile phones, there are App which are showing some level or accuracy to change in level in a environment.

 

So how do they do it on mobile phones, there are App which are showing some level or accuracy to change in level in a environment.

I don't know how it's done on mobile phones, but I do know that they have a variable gain amplifier, and so the level is (at a guess) derived from the AGC sidechain.
I implemented a digital sound level meter as follows:
MEMS microphone
amplifier with a gain of 12,
UDA1361 ADC, sampled at 24kHz,
A & C weighting curves implemented by IIR filters,
squared and averaged

 

Thanks that makes sense,

Just out of curiosity( different to my post), do you need any amplifier, what happens if you use digital MEMS PDM or I2S and use software compensation to work out the peaks and dB values.

 

Thanks that makes sense,

Just out of curiosity( different to my post), do you need any amplifier, what happens if you use digital MEMS PDM or I2S and use software compensation to work out the peaks and dB values.

PDM is a pain to use - the only way is to get a codec that can deal with it. (You can use a microcontroller, but you have to run an IIR filter routine at the sampling rate of 3.2MHz to decimate down to 44.1kHz)
I2S microphones are a great solution, they just weren't available when I built mine. I just had to do it via an ADC - the ADC was connected via I2S, (or actually I2S faked using the SPI input).

 

The data sheet says 10% thd at 115dBA, so that seems to be about 1dB of compression.

115dB at 10cm= 99dB at 20cm= 93dB at 40cm= 87dB at 80cm= 81dB (not loud) at 160cm (only 5.2 feet away).

 

Hi All

I am in need of a sensor module which can detect audio noise outdoors to check if the sound level goes beyond a certain dB level.

I am aware you can purchase a wide range of standalone sensors, but I am looking for any option where I can remotely monitor the values and also store them into some form of cloud storage. This is the reason why I am looking for a reliable module option.

I have seen some ardrino based project, but once would like an option which is more reliable interms of its calibration and stability.

Are there any module solutions, with either a UART or I2C interface?

Once I used Grove loudness sensor. I found it satisfactory:

https://www.seeedstudio.com/Grove-Loudness-Sensor.html

 

The Grove sensor has a wide adjustable sound level range therefore it is not calibrated.
It cuts very low and all high audio frequencies.
It has only one variable linear output but it can be divided into the levels you want.