Arduino dBSPL meter

[Rustie0125]

yes 1khz to 6khz .
sorry here is the link
http://netram.co.za/1097-electret-microphone-breakout-board.html  . under documents there is data sheet for the op amp and one for the mic. but i am still not clear on what the output voltage range is.

[polymorph]

What you need is a log detector. It accepts a signal and outputs a voltage that is a function of the logarithm of the input power.

They are meant for RF, but a few go down to DC. The AD8307, for instance. It has a 92dB dynamic range.
http://www.analog.com/en/rfif-components/detectors/ad8307/products/product.html

There are a LOT of samples of interfaces from the AD8307 to an Arduino. Most are for RF work, but to the Arduino side, it makes no difference what frequency is going into the AD8307.

https://www.google.com/search?q=bypass+capacitor+frequency+response&safe=off&espv=210&es_sm=93&source=lnms&sa=X&ei=O-zMUsSKIobuoATYiILoAQ&ved=0CAgQ_AUoAA&biw=1280&bih=886&dpr=1#es_sm=93&espv=210&q=ad8307+arduino&safe=off


So you just need sufficient amplification to put the signal you desire to measure well inside the dynamic range of the AD8307. You may have to do some cut-and-try and some work with a 'scope, but I suspect that electret microphone is a good start.

[Rustie0125]

I was hoping to stay away from IC's but it seems it s the only way.
i will see if i can order one.

Question i have is is the mic i have order has the op amp built in will it still word with this chip or do I need to just use a normal mic on the chip

[polymorph]

One 8 pin IC and a handful or two of passive parts sounds good to me.

You'll need amplification from the mic, anyway, so use the one with a built-in 100x Op Amp. You can always put in a level control after it, you'll need some way of calibrating it, anyway.