If you've ever wondered like me, why bluetooth speakers do not bring an audio output instead of an auxiliary input, this is the instructable for you.
Here i'll show you what i did with a cheap and small bluetooth speaker to turn a whole 5.1 sound system on a bluetooth high quality one.
Step 1: Tools We Need:
Step 2: Disarm the Speaker:
You need to disarm your bluetooth speaker to analice the circuit and to notice if it's hackable, as you can see in the picture, the blue board, is the bluetooth module, so begin seeking by there, search for the datasheet of the main IC of the bluetooth module so you can know the pinout and find out from where the audio come out.
Step 3: Isolate the Aux in Audio Jack:
The audio jack originaly is connected to the bluetooth module in the pins the picture shows with those red arrows, so we need to isolate the audio jack, disconnecting it from those pins that are inputs, so search for those tracks in the circuit board, and cut it has i show in the second picture.
When done, we are ready to use our audio jack as an output insted of a input.
Step 4: Setting Up the Output Jack:
Solder to wires on the L and R pads of the audio jack and then connect them to the outputs of your bluetooth module. In my case as you can see in the picture, they are connected to the output of an operational amplifier, but that was because i realized that the audio sounds better there testing on different places in the circuit board that I thought where audio signal following the copper tracks in the circuit board.
When done, you are ready to assemble the speaker and test.
Step 5: Testing It:
Search for the cable of your audio system, connect it to your new output jack, connect your cellphone to it, and play music, and enjoy it.