How to create autonomous bluetooth speaker

Bluetooth Audio Module SKU: TEL0108 is a simple to use Bluetooth 4.0 audio receiver that can convert
any wired headphones or speaker into a wireless device

Board also has MicroSD and USB ports to play files directly from storage. It is powered by 5V via micro
USB or via pins on board

To try Bluetooth board in action,  we turn this lovely chinese cat loudspeaker into an autonomous bluetooth
speaker with LiPo battery

Besides speaker itself and BT receiver, we will need: 

• 3.7V to 5V boost converter;
• 1S LiPo battery. 1250 mAh capacity is pretty enough for more than 6 hours of autonomous work;
• LiPo battery USB charger; 

USB powered loudspeaker has very simple schema - it is amplifier circuit, powered by USB.
Audio jack is a signal input and speaker is an output 

In our case speaker is inside cat’s body and amplifier is connected to it by wire

Overall power circuit is very simple: LiPo charger is connected in parallel to the battery and converter is connected in serial.

For test we will power speaker from BT board’s USB used for pendrive

Connection to BT board is simple: there is no PIN, BT device name is “Xpecial Audio”

And name cannot be changed...

Also playback can be controlled by onboard buttons. But we will not use this option for now

Complete schema is still very simple.

Besides previous power circuit we added power switch and soldered amplifier channel in 

directly to BT receiver

We just put it from the back side of BT board using a piece of duct tape

And a small tip:

Do not set volume of amplifier to maximum. Remember the rule - amplifying a signal you also amplify the noise.

On maximum volume noise is hearable. To reduce it just put volume level for about 50%. It will be still enough for loud music, but with less noise

That's it! Feel free to ask the questions:)

Links:

Bluetooth Audio Receiver Module - https://www.dfrobot.com/product-1532.html
Board wiki - https://www.dfrobot.com/wiki/index.php/Bluetooth_Audio_Receiver_Module_SKU:_TEL0108