After weeks of waiting, the parts I needed for a homemade Bluetooth speaker arrived. Pictured above are the PAM8403 amplifier board, Bluetooth module (USB powered with a 3.5mm audio jack), and a couple of 3-watt speakers. The power supply is a 5V 2A power supply I had laying around. All of the project materials amounts to roughly�$13.
The project itself was simple enough: Break open the Bluetooth module, apply power to it, and then take the audio signals to the amplifier which would drive the speakers.
Here's the Bluetooth module cracked open. My original intention was to remove the audio jack and USB plug to end up with a flat board, but the desoldering did not go well as I didn't have any solder wick. After some failed tries with my desoldering pump, I ended up cutting off the edge of the board with the USB plug, and giving up�on removing�the audio jack. There were two copper pads near the USB plug that were labelled Vcc and Ground so I used them to apply power instead of bothering the with the pads of the USB plug.
Wiring it together did not go as simple as I thought it would either. I tried connecting wires directly from the pins of the audio jack to the amplifier board, but it�didn't work. The audio jack was still working with headphones, and the speakers worked faintly when connected directly to the audio jack. (The speakers arrived a bit banged up so I was worried they may have been broken.)
After some time troubleshooting, I ended up replacing the PAM amplifier board (I bought a few, exactly for situations like this) and spliced the included 3.5mm audio jack cable and used that to connect to the amplifier board. I was so happy to hear the power-on tone that the Bluetooth module makes!
After some playing around with it, I realized that there was only static coming out of one of the speakers so I chopped that one off.�I'm not a audiophile by any means so I'm easily impressed...�I was pleasantly surprised in the audio quality from these cheap speakers. Even with just one speaker, it can get pretty loud without sounding bad.
Time to put everything into an enclosure! This was my first time using foam board. If I didn't use foam board, I'd�still be using�cardboard. Now that I've given it a chance, I can definitely see foam board being my go-to material for this sort of thing. My cuts are a little rough but I learned later on that using a new blade and/or cutting at�an angle will give you cleaner cuts.
I used some needles to keep the foam board in place while I used hot glue everywhere.
Once I was finished putting it together, I printed out a simple nameplate for the speaker.
The Bluetooth module board�has a blue LED that blinks rapidly when it isn't connected, and once every 3 seconds when it is. Honestly, it wasn't intentional, but my design with raised bottom, which was intentional, worked in the LED's favor as it gives it a neat glow underneath the speaker. The nameplate originally had a note about how the rapid blinking meant it wasn't connected, but my printer wasn't having�it...
So that's it! It only took me half the day from start to finish and I am satisfied with the final product. I hope you'll take this post as inspiration to whip up your own Bluetooth speaker!