RMS calculation for acoustic signal

Using Arduino Project Guidance
1

Hello,

I want to work on a project with Arduino boards 'To calculate RMS value for the acoustic signal'. Please guide me through my task, which board to use and what further to do. I am good at programming. I am the beginner to embedded platform and learning the concepts now.

Thanks & Regards,

2

You need to digitize the audio signal. This will control what the fastest audio frequency you can measure. For a Uno this is about 5Khz but for a Due is in the region of 330K.
You need to use an input conditioning circuit like the one on the front end of this:-
http://interface.khm.de/index.php/labor/experimente/arduino-realtime-audio-processing/

Then take samples over one cycle ( that is the hard bit knowing how long one cycle lasts ). Take the samples square them, add them all up and take the square root.

3

I am the beginner to embedded platform and learning the concepts now.

Do you have a microphone/preamp circuit? Before you worry about calculating RMS, you've got to be able to convert sound into ADC readings.

[u]RMS[/u] (Wikipedia).

For real-world sound, you'll need more than one cycle because every cycle will be different. It's a question of how much averaging/smoothing you want.

If you use the conditioning circuit to bias the signal, don't forget to subtract-out the bias.

4

Thanks Grumpy_Mike. I am working on it. I want to do it on Arduino DUE board + LCD TFT display. will my selection work ?

5

Thank you DVDdoug. I will work on it.

6

chikkala:
Thanks Grumpy_Mike. I am working on it. I want to do it on Arduino DUE board + LCD TFT display. will my selection work ?

Yes it will although you might have trouble with the display, you might find that the library for the display will not work on the Due and you might have to write your own.

7

oh ! Thanks for alerting me about the display Grumpy_Mike.
I don't want to complicate this project and want to do it in a simplest way possible since I don't have enough time. So, I changed my selection to seven segment display instead of TFT LCD. The seven segment display just require four pins and I have program readily available for it. Shall I continue in this way ?

8

it is entirely up to you - it seems a plan