Keep-whole modulesKeep the moduleUnplug and unscrew

Bluetooth audio module

Also called BT board, A2DP module.

The small board in a Bluetooth speaker that takes the radio and outputs analog audio, sometimes with the amplifier on the same board. Reusable if you can find power, ground, and the speaker outputs. Not a general Bluetooth serial link unless the chip is one of the rare configurable modules.

If you are new to this category

Some scrap is already a finished object: a webcam a computer recognizes, a barcode scanner that types numbers, an amplifier board between a jack and a speaker. Opening these to pull a chip almost always throws away the useful thing. If it still works when you plug it in, stop there.

Test the whole module before you unscrew it. A working webcam is worth more than the parts inside a dead one.

Stop when it still works

Plug the module in before you take it apart. A webcam the computer already sees, a scanner that types into a text box, or a speaker board that plays music is the finished part. The chips on the board are not an upgrade.

Lithium-ion cells. A punctured, crushed, overcharged, or reverse-charged cell vents and burns hot enough to ignite the bench. Swollen pouches are already failed.

Specification. The right-hand column is what is typical. The label on the part in your hand wins if they disagree.
What to look for	Usual figure
Supply	Often 3.7 V from the cell, or 5 V. Look at what the battery connected to.
Pairing	The button is somewhere on that board. Keep the button.

Volts are electrical pressure, amps are how much current is flowing, and ohms are how hard the part resists that flow. A higher voltage than the part was built for is how salvage parts die on the bench. If a cell in the table says “read the stamp”, that stamp is the whole specification.

What people actually use it for

Adding audio to a dead speaker cabinet that still has good drivers

Leave this one when

The antenna trace is torn off the board. Range goes to nothing.

Buying a new one is the better idea when

A new audio-receiver board with labeled pads. Your time is worth more than the mystery board if the pads are not obvious.

How to tell if this one still works

Original battery voltage, original speakers, hold the pair button, see if a phone sees it.

Tools you will want: Meter, Phone.

Where people actually find it

3 notes, most useful first. “Leave it” means the part is in that machine and you should not take it: it is dangerous, worn out, or only useful if you already know that exact repair.

Harvest at a glance
From	Call	How many	How often	Where it sits
Powered or Bluetooth speaker	Worth it	1	sometimes	Portable speakers.
Game controller	Leave it	1	sometimes	Wireless pads.
Motorized toy	Leave it	1	sometimes	The 2.4 GHz board.

Worth pullingPowered or Bluetooth speaker1 · sometimes
In this particular machine
Audio Bluetooth, sometimes combined with the amp.
Where to look
Portable speakers.
How to get it out
Keep the button and the antenna.
The condition to expect
Good if the battery was the fault.
Leave it — present, not yours to reuseGame controller1 · sometimes
In this particular machine
A proprietary link, not a general Bluetooth module you can reflash.
Where to look
Wireless pads.
How to get it out
Leave it.
The condition to expect
Not a radio project.
Leave it — present, not yours to reuseMotorized toy1 · sometimes
In this particular machine
A proprietary protocol.
Where to look
The 2.4 GHz board.
How to get it out
Not a radio you can retarget.
The condition to expect
Leave it.