Last night was rather frustrating. How hard could it be to get a simple microphone working? Apparently it can be rather hard.
The tricky device was a very small microphone (4 pad QFN package) , specifically the Knowles SiSonic surface mount MEMS microphone. Since it only has 4 pins, it seems like it can't be that difficult. But, it was. This is the website:
http://www.knowles.com/search/products/m_surface_mount.jsp
After a few hours of tinkering, it turns out there is just not enough gain in they system. The microphone should be connected to a variable resistor to control the gain, but we found out the microphone works if the resistor is shorted, hence creating the maximum possible gain. Even then, it would have been nice to have more gain -- something to think about in the next circuit?
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