HAND-BUILT PORTABLE BLUETOOTH SPEAKER
A Bluetooth speaker has always been something that I've never needed, always wanted, didn't have money for. Its one of those things that you always feel like would be better to have. After unintentionally getting my hands on a cheap and ugly pair of small USB powered desktop speakers, I had the brilliant idea of converting them to a portable Bluetooth speaker.
The Bluetooth Audio Board ($10)
For this, I used the DROK Bluetooth audio receiver board from Amazon. Out of several different types of boards I've tried before, other than the Asian accent connection voice prompt, this one is the best, most reliable, and highest quality out of all of them.
The Amplifier and speakers ($0)
I already had a set of USB powered desktop speakers in which I salvaged the speakers and amplifier from. The metal mesh I used on my build was also from them. I recommend going to a thrift store and repurpose some speakers they have there.
The DC/DC Converter ($5)
Upon the first test of the circuit, I notice there was a little noise coming from the speakers. At first, I thought it was due to the Bluetooth or the relatively minimal amp, but after some research, I found out it was due to a ground loop between the Bluetooth board and amplifier. It was easily fixed by adding a DC/DC converter between them.