Hello,

I'm new to the mbed, I am producing a wireless enviromental monitoring system, I have already got my temp sensor working fine. But my next issue now is getting the microphone to work. I'm abit lost of what needs doing more hardware wise, The datasheet says I can either plug it straight into a "ADAU1761" or use a amplifer "ADA4897-1".

I would like to connect it straight into the mbed using the analogin if possible and let it sample it for me. But I feel it may require a amplifer. Can someone give me a little guidence of if I can connect it straight to the mbed or if I require to produce a circuit for the microphone before hand.

If I have to make a circuit I was thinking I need a low pass filter at 20khz, and a amplifer.

Matthew,

Looking at the data sheet the output of the ADMP504 is not really high enough to be used directly with an mbed A/D input, on the other hand the ADA4897-1 is a great match if you connect its supply to the mbeds 3.3v output. So i think using the ADA4897-1 is a good way forward.

Dave.

Thank you for the information and have put the ADA4897-1 on order. When I come round to sampling this microphone do I just use the analogin pins or is there a A/D input as how you wrote it sounds like they're different pins.

Regards Matthew

Matthew,

There are 6 analogin pins p15-20 just choose one. The 3.3v pin is the 3.3v power out on pin 40, you can use it to power the ADA4897-1, which will ensure the output will be limited to 3.3v, thus protecting the analogin pin.

Dave.