Seeing old analog wireless headphones in the free-for-all bin in the Munich Maker Lab I looked around for a easy solution to enable them with bluetooth.
I found the OVC3860 module (5$) which integrates an bluetooth module with HiFi and headset profiles, an headphone amp, lipo loader and even has some pins for easily attachable buttons.
I've put the module in one side and an old 370mAh lipo with an separate charger in the other.
- 3 buttons on the side to control Play/Pause, Next, Previous
- NFC sticker to setup up the bluetooth connection
- Audio port usable as a line out (with volume turn low) or speaker in (with audio module off)
Total cost of the project: around 10€