Large iPod Inline Remote for use with any Head phones/Ear buds

We have all seen the instructables that take an existing pair of ear buds with in line remote and hack them with a 1/8" jack so you can use your favorite set of headphones while maintaining the mic and remote. While that is a great and easy hack you are left with 2 problems. For one your stuck with an extra 2 feet or more of wire to contend with. Secondly you still have that tiny remote that can be difficult for some people to operate and almost unusable with gloves. With that remote being in the middle of 6 feet of cable its also hard to keep track of and get to. 

In this Instructable we'll take a look at the inner workings of the in line remote. We will then create a larger remote that will fit inside of an Altoids Smalls tin. 

Materials Needed:

• Expendable or broken set of iPhone/ iPod Touch Ear Buds with Remote
• Altoids Smalls tin
• 3 small push buttons
• 1/8" stereo jack
• small Perfboard
• pair of right angle headers
• small rubber grommet 

Tools Needed:

• Soldering iron
• Wire cutters/strippers
• Razor blade
• Small torch or lighter
• Sanding block with 150 grip sand paper
• Jeweler's file set.

Step 1 Inside the Remote

First we need to take our razor blade and carfully pry apart the case around the remote. Here is what we find on the inside of a set of iPhone/iPod Touch compatible ear buds with remote. I've labeled as many parts as i could without the use of a microscope. I've also labeled the TRRS jack. Only the Ground and Control/Mic wires are used by the remote. 

After hours of research and experimenting, with my limit knowledge, i have no idea how it all works. What i could find online seams to indicate that the circuit board in the remote triggers the iPhone/iPod into excepting various signals between the Ground and Control/Mic wires. I do know that the Play/Pause/Skip button shorts the Control/Mic wire to Ground. But if you connect a TRRS jack up to the phone, start up some music, and short the Control/Mic wire to the Ground wire, nothing happens. But if you short those wire at the remote you will trigger the iPod to ply/pause/skip. As for how the circuit triggers volume control i have no idea.

Here is what i do know. When the headphones are plugged in there is about 1.9V DC on the Control/Mic and Ground wires. When the cable is not connected to anything there is about 0.87 Ohms on the wires. When the Volume + button is pressed the resistance drops to 0.85 Ohms. When the Volume - is pressed the resistance drops to 0.86 Ohms. That doesn't really mean much since there is more going on there then a couple of resistors. From what i can make out there is 1 transistor on the board and an IC with 6 leads. 

So to keep things simple we will used the existing board and just extend the buttons on the board to our larger push buttons.