Pause/Play music with pressure sensor with a headphone

Hello people of the forum,

I'm busy trying to create a pause/play on a headphone that works like a button if you use in-ear plugs.
At the moment I'm stuck in a process which i need help with :frowning:

I will explain in the details so you know the concept.

Idea: With pressure sensor to detect the user is wearing the headphone, when the user takes the headphone off the pressure sensor can see that the pressure is gone. We bought a headphone with a 3 pin jack, after research we noticed that we need a 4 pin jack.
That means a 3 min has a GND, left and right sound. on a 4 pin jack you have GND, left and right sound and the mic output line.
The information we got is from here: http://www.instructables.com/id/Galaxy-Nexus-and-others-headset-remote-with-medi/
What we know is that this function on the headphone will only work on android because the apple devices uses different pins.

My current process :
We changed the 3 pin jack to the 4 pin jack, only problem is that the right ear has no sound but thats fine the left side works.
We tried to use a jumper wire (it works like a resistor and gives 0 ohms) and put that on a pin for example 13, this jumper wire is our mic output signal. What we want to do is give pin 13 OUTPUT low then OUTPUT high to see if it pauses and plays. low should be giving no ohms.

On this forum the question was asked about resistors.
http://forum.arduino.cc/index.php?phpsessid=mqid6siccjoop2ntir13hetuh0&topic=272738.0

Pressure sensor if else statement works.
Mic output signal is put in the arduino but it does not pause the song and play it.

It is pretty much information but i hope it is understandable.

TL;DR We have a mic output line on arduino at example pin 13. With the pressure sensor we give it OUTPUT LOW when the headphone is not being weared and HIGH when its weared.
The phone does not pause or play the song.

Thank you in advance.

First, you should test the basics....

While the headphones are playing, connect the 4th pin to audio ground. By that description, it should do play/pause. If it doesn't, either you're playing with the wrong wire, your phone doesn't support it, or something else is wrong - this needs to be figured out

Assuming that works, using a multimeter, measure the voltage on that 4th pin relative to audio ground. What's it at when? Is it being pulled up to the cellphone's battery voltage (what you're hoping for, I think)?

To drive it with an arduino, you'd need to have the arduino ground connected to audio ground (this is potentially problematic if both the phone and arduino are plugged into the wall) - and you'd need to make sure the voltage the Arduino as high was safe for the phone (it probably isn't). I'm not sure there's any reason to have a whole Arduino here though - I'd try to avoid having an MCU to control this, if possible, since it'd make for a rather awkward headset.

But yeah - you need to do some more data gathering to figure out exactly what you need to do to achieve this.