Has anybody some experience with the SparkFun-electret microphone connected to the Arduino board -> http://www.sparkfun.com/commerce/product_info.php?products_id=8669
I would just need to interpret the volume with the Arduino board...
Look at the schematics here:-
http://interface.khm.de/index.php/labor/experimente/arduino-realtime-audio-processing/
If that does not give you a big enough signal to use then youu will need an amplifier.
I use the same board as yours, sampling the signal with an analog input with no problem.
In my opinion the gain of the amplifier could be a little more as there is a lack of sensitivity at low level. Just a resistor change to hack the board.
Not being an analog wiz, can someone comment on the audio out portion of that schematic for me?
A PWM is a square wave with a given percentage duty cycle. They pass it through a series resistor, then a black box labeled "RC Lowpass Filter" with a value of 33 mH. (milli-whats? part example?) Then a 10 nF cap bridges the audio jack on the way to ground. I am guessing the low-pass component basically erodes the shape of the square wave, such that a 90% high duty turns into a ~90% amplitude on a curvier waveform, etc.? I expect this is easier to see on a good oscope.
33 mH. (milli-whats?
milli Henry - The Henry is the unit of inductance.
The low pass filter is to stop aliasing when you digitise it at low sample rates.
Informative as ever, Grumpy_Mike. Is the part indicated JUST an inductor of that value (relying on the R and C we see), or is that a combined package that includes an inductor and matched support parts?
No it's just an inductor. I have never come across a combined inductor / capacitor except in interference suppression stuff. To build a filter like that would restrict the use of a component to very specific applications, something a manufacturer would no want to do.
Hi GreatOne,
I'm using the same microphone board without problems. The board has an amplification of 100 and already includes bandpass filters ( look at the board schematic).
What is your problem?