Sending a signal from an arduino to an iphone via trrs jack

Hi all,

I don't know if I posted this in the right topic, but here goes.

I'm doing a project for school and I need to connect an arduino together with a pair of headphones to a smartphone (iPhone or Android). And I've connected a force sensitive resistor to the headphone and I need to send a signal from the arduino to the phone when it senses the headphones are taken off.

I just don't know what to send to the phone. I know the if statement needed for when the sensor drops to a certain value. http://lifehacker.com/5904280/diy-headphone-adapter-adds-pause-play-and-a-microphone-to-any-smartphone-headphone-jack The youtube movie on this webpage kind off sums up what I want to do. I just want to make the arduino act as the button.

I hope you can help me!

I just don't know what to send to the phone.

maybe a signal over bluetooth ?

On the phone there must be a receiving app of course

No it must be via the trrs jack. I hoped I wouldn't need an app, I would like to apply the code so the music app reacts to it.

SO you are saying that as in the video you linked, you are adding the push button to the TTRS jack. But what you want is the Arduino to act in place of the push button? If so just obtain an Ardunio and a relay module. Use the relay module controlled by the Arduino pins to act as the button.

But can the relay module make sure that I can pause and play the music? Not just pause it or disconnect the audio signal while the music is still playing.