MEMS mic as basic sound sensor

Hi all,

I got a few of these MEMS microphones...

http://www.ekulit.de/wp-content/uploads/datasheets/200640%20MS4.3-42.pdf

which I was hoping to use to control a robot that hangs from and rolls along a thread. I was planning to use two Mics and simply compare their signal strength to have the robot go towards sound.

I was hoping I could use the mic component without an external opamp, but I am having a hard time reading it's data. I copied the circuit found here...

http://academy.cba.mit.edu/classes/input_devices/mic/hello.SPU0414HR5H.png

I get very little response. I have to tap or blow on the mic to get it to register a change. I don't need any audio quality at all, just a basic level. is there a way to use an arduino nano to amplify the signal enough to register sound?

The other funny thing is, I am using the external AREF pin connected to the 3.3v pin(same as the mic) and the values hover around 140...

Thanks for any tips!

I am not surprised. Look at the pdf. The mike has two ground pins. The circuit board has only one for the area shown as "mike". Isn't the board designed for two ICs? I see them shown on the silk screen layer.

Paul

the mic on the board is this one

http://www.digikey.com/product-detail/en/SPU0414HR5H-SB/423-1134-1-ND

which uses one pad as gain, which connects directly to ground for max amplification. I tried various configurations with the C3 capacitor, but none seemed to work.

I'm wondering if I can use the ADC(ADMUX?) but access some of its gain capabilities to amplify the signal to the point that audio signals can be read.

I see what you mean, Paul.

The board is designed for an atTiny*5, but I figured I could just run the mic through an arduino instead. I basically used the same configuration to input to the arduino as it says here for the tiny45. Not sure if I fried the mic while soldering or I dont have the gain correct.

A real schematic would be much better than a circuit board layout.

Paul