Sorry, it's my fault for not thoroughly explaining my project. I was posting this in another forum where I have described it better.
I am building a small "portable" sound and vibration device. I can sense vibration through the electret mic but I would like to have a separate/more accurate vibration meter (that I have purchased).
I could post a video to explain what I am doing if that helps.
Magician, your article is nice. My goal however, is to make a sound level meter (and a vibration meter on the side). In your article, the vu meter, you are taking the signal from the input and display it on your LCD. The concept of the sound level meter should be simpler than the vu meter right? How do I make the simple conversion from V do dB? Through rms? Sorry, I am confused.What about the sampling rate?