Instead of buying expensive Bluetooth headphones, you can turn any old set into wireless cans. Instructables user FuneLab shows you how, with his DIY BluetoothBox.
Bluetooth is definitely more convenient for headphones, even if it isn’t quite as high quality. The BluetoothBox is a tiny device with a standard 3.5mm audio jack for any headphones, and a microUSB port to charge it. On a single charge, it will last for about six hours, which is comparable to most Bluetooth headphones. Just plug in your favourite headphones and you’re good to go.
Check out the link below for step-by-step instructions, a materials list, downloadables like schematics and 3D printing files, and any other instructions you might need. Fair warning, this isn’t a project for someone who isn’t good with electronics. If it seems daunting, head to your local hackerspace so that experienced DIYers can help you out.
BluetoothBox for Stereo Headphones and Speakers [Instructables]