Source localization on a laptop

Question

I have been trying to achieve sound source localization for a long time with two mics using the ITD method and have gone through various articles on the net.

I want to know if its possible to actually achieve sound source localization using two MEMS mics with a high gain (https://www.sparkfun.com/products/9868) or using two headphones with mics to the computer or with just one headphone attached to the laptop and one internal mic of the laptop.

I initially tried to use an arduino uno with matlab for processing but the resolution (high sampling rate) for getting a time difference could not be achieved. Chris Stratton from the arduino stackexchange recommended me to try to connect these mics to the laptop directly. Link to the discussion there

Please recommend any reasonably priced device(jack) for connecting the two mics (or one only if it is possible to read 1 external and internal laptop mic simultaneously) to the laptop for matlab processing. Currently I have a windows 10 laptop with only one audio input. I guess I would need some sort of a splitter maybe. In matlab the audioreader command needs a device id too which I am not able to see when I connect any external mic to the laptop(using audiodev info).

P.S-Another challenge is code wise how to read simultaneously from two external mics or 1 external and 1 internal mics. Would be grateful with any help.

Answer 1

How do I input two mics simultaneously on a Laptop?

To be able to input two mics simultaneously on a laptop, you need a two channels audio interface with two mic inputs. Using one interface for both mics will guarantee that both signal are digitized by a common clock, which is a must for your application.

There are numerous options for such an interface, with varying prices, and specifications. Look for one with USB interface to your laptop and that is supported by your Windows 10 OS.

Can I use these MEMS mics

Probably yes. Nevertheless, you have to setup the needed hardware to power them and convert their output to an appropriate signal to get into the mic inputs. That might imply adding components to have proper level and impedance. This question would probably be better answered on https://electronics.stackexchange.com/.

The idea of using one of these with a combined headphone/mic seems just adding hassle and I wouldn't go this way.

How do I setup MATLAB to record/process the audio

I don't use MATLAB and don't have a license to do tests. I would nevertheless expect that once your audio interface driver is properly setup on your laptop, this interface should be recognized by MATLAB. If this is not the case, that is an issue not related to sound design, and this issue should be dealt with either on MATLAB support forum if there's one, or maybe on https://stackoverflow.com/ where there is a matlab tag.