How to detect power input to a USB port for EEG project.

[Superposed_Cat]

Hi, so I want to build an EEG and have it send data to my laptop (windows 8). But how would I go about writing a C#(or C++ but I'm more comfortable with C#) program to detect the input (the different frequencies). I was hoping to be able to treat it as a like a music input but I can't seem to find an sdk/api for that. Any help appreciated.

 

[Student100]

How exactly do you plan on capturing the input? What protocols are you going to use to send the data?

 

[Superposed_Cat]

That's the thing. I've never interfaced with an external device before. I've only ever coded things like basic two-dimensional games, process managers, bots, things to do my math homework for me etc nothing even remotely within the sense of the word online. So no protocol so to speak. as far as the EEG I was just(roughly) going to connect EEG electrodes (ordered online) to an amplification system (using op-amps) with circuitry to isolate the ambient noise (hopefully) and convert the analog to digital. I admit this was just some random idea that came to me at 11:30 on a sun (time zones). But as I say any advice welcome. Is there nothing that can just pick up that noise and convert it to plottable values?

 

[voko]

It might be easiest to use the microphone or line-in port. The sound hardware will already have an ADC. The only catch is that there is probably going to be a high-pass filter to suppress the 50/60 Hz noise, and the most interesting EEG frequencies are below 60 Hz AFAIK. You could get around that by modulating some higher frequency (say 1500 Hz) with the EEG signal.

 

[Superposed_Cat]

I see why you have a thanks badge, so but how will it read from the audio jack?

 

[voko]

You can use whatever recording software you have. Capture the audio signal and save it as a wav file. Then analyze it. A bit clunky, but this probably takes the least effort to get your setup up and running.

If you want to analyze the signal in real time, check this out: http://stackoverflow.com/questions/510019/capture-a-microphone-audio-stream-using-net-framework

 

[Superposed_Cat]

Thank you so much.