Hi everyone!
(There is an improved version here!)
A couple years ago, I got this headphones for free, buying a shirt.

And of course, after using them daily, the cable began to fail.

So, I leave them inside a box, and a few months later, searching for a bluetooth headphones, (after losing each one of my last headphones 'cause cable issues, i must learn something right?) I discover a "bluetooth hands free car kit".

Suddenly, it all came to me, and the idea for this instructable was born!

Step 1: The Materials and Tools

So, I bought the cheapest bluetooth hands free I could found (the first one came broken, that's why there are some holes and pieces of plastic missing inside the headphones, from the previous attempt) and, besides it, every tool and material I allready have it around. Some piezes are not that common, but they come from dispossal computers, and broken cables that any friend could have.

Here is the materials list:

Some old/broken headphones, with the audio cable coming out for one side only.
Mini Bluetooth Audio Receiver (I got the TS-BT35A08 on DX.com for about 7 dls http://www.dx.com/p/ts-bt35a08-mini-portable-bluetooth-v3-0-edr-audio-receiver-w-mic-black-355910#.V_6kGH81GCg)
A Paper clip
2 CPU Front Panel Cables (I use some frome and old CPU, but if you don't have one, I found some on Ebay from around 1 buck http://www.ebay.com/itm/65cm-ATX-Off-On-Reset-Power-Switch-Cable-HDD-LED-Front-Panel-PC-Replacement-Wire-/321969980975?hash=item4af6e8062f:g:V0oAAOSwT~9Wj1fC)
Epoxy Clay
A Micro USB Cable
Thermofit / Heat Shrinkable tube
Isolation Tape

Here is the tools list:

Utility Knife
Soldering Iron
Drill

Step 2: Taking Everything Apart

Ok, first, we need to take apart the speaker on the side where the cable come out

To prevent some damage between the magnet, the audio wires and the bluetooth, i put some isolaton tape over it.

Then, I split the plastic over the bluetooth chip. No more to do here

Step 3: Soldering the Headphones to the Bluetooth Module

We have 2 speakers and only one cable, wich means we have a left audio wire, a right audio wire and one ground wire, wich conects both speakers on series.

The audio jack from the bluetooth, has 3 pins from left to righ:

1st left audio, 2nd right audio and 3rd ground.

The first and second pins could be used on any order, as long as the third pin remains ground

Step 4: Making the Charging Cable

The hole for the audio cable was so small, that I could'n fit a female micro USB Port, so i came with the idea of making a specific charging port, using a USB cable and some front panel cables.
Before I explain the process for tha cable, feel free to improve my solution, as long as you keep 2 cables to conect the positive and ground sides of the chargin micro USB port, to a 5V power source.

Now:

This cable comes in 2 parts, one inside the headphone to conect the bluetooth charging micro usb port to the audio cable hole (Lets name it Panel Cable A), and another one for the USB cable conversion (Lets name it Panel Cable B)

Panel Cable A

Cut the plastic of the micro USB cable until the pins are exposed
Solder one side of the Panel cable to the 1st pin of the micro USB cable, and the other side to the last pin
Using som epoxy clay, lock the panel cable tip inside the audio cable hole

Panel Cable B

Cut the paper clip to get 2 pieces of 3/4 of an inch.
Fit the paper clip pieces inside the holes of the panel cable.
The USB Cable has up to 4 wires, 1 red (mostly positive) and 1 black (mostly ground). Solder each one to the front panel cable.
Isolate the wireswith shrink tube

Also, this is a good time to drill a hole on the headphone cover, to gain access to the on/off switch

Step 5: Fitting the Parts

The Panel Cable A needs enough space to connect into the Bluetooth, and turn back to the audio cable hole. Use the utility knife to cut some material.

Also, in my specific case, the space between the magnet and the back of the headphone case, was so small, that i need to put the batery next to the bluetooh.

After everything is align, use som epoxy clay to fix the parts inside the case.

When it's dry, simply close the speaker on the case to keep everything inside.

Step 6: One Button to Rull Them All!

Now that everything is inside, we need some easy way to push the On/Off switch.

I came with the idea to use some transparent acrilyc with a small hole to cover the chip, and a screw inside the hole to push the button.

Also, I add a thin layer of epoxy clay over the screw head, to prevent the switch to get stuck inside.

Later, I place it over the hole and glue the acrylic piece in place.

And thats all! I hope you enjoy this Instructable, to recycle some old headphones.

Please leave a comment or a suggestions, to improve it.

Step 7: Finished!!!

We're done!

The bluetooth battery last around 6/7 hours of continuous playing.

Press the On/Off Switch 10 seconds to enter "discovery mode" and connect your phone to "DL-Link"

Press it around 3-5 seconds to turn it on or off.

Hope you guys like it!