Portable Stereo Speaker

We are looking for a cheap and efficient way to charge the amplifier and the Bluetooth module. We are trying to use a remastered version of the Minty Boost from Adafruit to deliver a 3V-voltage to the Bluetooth module and a 12V-voltage to the amplifier. Not working well though, the current is far too high from what we should observe according to our calculation. The sound from the speakers is very noisy.

Now that I have received the module, I have added it to the circuit accordingly to the scheme. The LED is blinking when the module is on and stays on when a device is connected.

At first I forgot to solder a simple wire to the "EN" pin (for enabled I presume), it simply did not work... After correction, it worked pretty well! Next steps are to deal with volume pins.

To supply 12V power to the stereo amplifier, we worked on a little device that deliver it with to AA batteries. We are going to write another hackaday project for this one.

A few days ago we received the chips we hadn't to start the stereo. So we ran the tests on a breadboard and it worked pretty well! A few noise we reduced using 47pF capacitors at the audio input.

So I updated the scheme and added the second speaker. As we have not receive yet the bluetooth module, we are simply using a jack to test the whole thing. We got a 60mA current for a 12V voltage.

Now waiting for the bluetooth module to arrive! I also need to work on the design of the box to get good results in low frequencies and how to integrate volume control buttons in the box.

I also ordered another audio power amplifier, the LM386, to make other quality tests.