Controlling ard. via cell phone using headphones(?)

Hi,

I'd like to let my arduino "sense" incoming calls on my cell phone, I know there are a lot of ways, but I thought of this very rude one and I'd like to know what you think about it. Essentially, I link headphones to my phones, I can work on the cell settings so that when a call arrives the sound comes off the headphones and not the phone's speaker. So If i cut off the one of the headphones' speaker and pull out the wires I have an input voltage controlled via phone, right? I know this must be a very rude and inelegant way, but do you think it could work? I've tried but I'm stuck in a silly proble, I don't get what's inside the headphones' wire, I can't find the conducting wires :(

If the data from the headphones is audio data, it is very low current, AND is alternating current. AC and Arduino don't go in the same sentence.

You'd need to rectify the AC, and amplify the resulting rectified output to get anything usable.

Even then, I have my doubts.