Bluetooth speakers

This is a custom (DIY) bluetooth speaker.
Very loud, but not so good audio quality. Maybe need better speakers, on different design.

* Mainboard: WAVGAT **MH-M38** (You can find it at aliexpress)
**Functions:**
* Bluetooth 4.2 support
* Stereo amplifier (2x5W)
* A2DP support and losless audio playback
* Internal Li-Ion 3.7v battery charger/controller/power
* USB-Audio card mode
* Optional 4-key functions (volume/track change, mute, power). Not present in M38, but support by chip
* Speakers: 2x3W, 4Ohms, 40x18mm
* Lithium Battery Capacity Indicator board (for 1S)
* 2x18650 betterys

TODO:
* Add buttons for control volume, track (next/prev), mute and power on/off.
* Try another speakers...
* Improve audio quality?