A Modular, USB Powered, Bluetooth Speaker System

Published by frenoy on

We learn how to build a simple, yet very useful USB powered, Bluetooth speaker system that uses a modular enclosure.

Step 1: Watch the Video To Get An Overview Of The Build Process

This video will give you an overview of the entire build process, details about the enclosure and electronics involved. It would be advisable to watch it before you set out to build this speaker system.

Step 2: Gather All The Electronics

Electronics Layout

I would strongly recommend you purchase the Bluetooth module and the amplifier as a combo like the one shown in the video as that will simplify the wiring for you. If you have previously purchased a BBox2 unit then you can use the electronics and speakers from there.

We will be using commonly available 2″ (51mm) full-range speaker drivers along with a microUSB breakout board for the input power. We also build a small filtering board consisting of a 100nF capacitor for filtering along with a 1000uF electrolytic capacitor which acts as a reservoir capacitor. The combo amplifier module that is available online works from a single, 5V supply so you do not need to add any more electronics to the filtering board. However, if you use the amplifier module from BBox2 then you will need to create a 3.3V power supply as well and we will be using the LD1117 linear regulator as the Bluetooth module does not draw a lot of power.

Step 3: Build The Filtering Board

5V Filtering Board Wiring
5V Filtering Board
5V & 3.3V Filtering Board Wiring
5V & 3.3V Filtering Board

The filtering board is optional but I recommend adding it as not all USB power supplies can deliver the frequent current bursts that are needed when playing low-frequency beats at high volumes. Once again, if you are using the off-the-shelf combo module then you only need the 5V section. If you are using the module from BBox2, then you will need to create the 3.3V section as well. Refer to the wiring images shown. Once the filtering section has been built, solder the USB breakout board to the input.

You can also add a switch to control the power to the system and there’s more information about this in the step about the enclosure.

Step 4: Wire It Together & Test

Combo Module Wiring
BBox2 Module Wiring
Testing The Setup

Once you’ve created the power supply section, solder some wires to the speakers and start wiring it all together. When you first power on the system, the two LEDs will blink rapidly, indicating that it needs to be paired. Use a smartphone or computer to scan nearby devices and the Bluetooth module should show up as either the CSR8645 or the F-3188 module depending on the firmware loaded onto the actual Bluetooth module. Simply tap the name to pair and once paired, using the speakers is as simple as playing some audio. You can use the volume buttons from the phone to control the speaker volume but do keep in mind that you can also control the volume from the physical buttons themselves. If for some reason the speakers don’t sound loud enough then you can adjust the volume manually using the buttons.

Make sure everything works before moving on to the enclosure. Don’t worry about the sound quality as the enclosure plays a huge role in enhancing this as you will see later.

Step 5: Build An Enclosure

Example Cardboard Enclosure
Example Enclosure That Uses A Can
Making A Hole For The USB Board
Gluing The USB Board
Final Left Speaker Section

I strongly recommend using an enclosure for this build as it enhances the final audio quality – both in terms of loudness and the actual tone. You do not have to 3D print an enclosure and you can also use a cardboard box or can as shown in the images.

If you decide to 3D print an enclosure, then here’s a link to a very nice one that I will be using: https://www.thingiverse.com/thing:2446587

I used an old soldering iron to make a hole in the amplifier enclosure and this is where I planned to mount the USB board. I used hot glue to support and hold it in place. Mounting the speakers was easy enough and I used version 1 of the speaker fascia as these were perfect for the speakers I had. I used 6×1/2″ or 3.5x13mm self-tapping screws to hold everything in place. The 3D model also had a small hole on the amplifier cover for a power switch and so I decided to add one. The switch sits in series, between the USB board and filtering board.

Step 6: Wire & Place The PCB Inside the Enclosure

Final Test
Final Build

Next, we need to wire it all again and then place the PCBs into the enclosure. I used double-sided tape to hold them in place. Once this is complete, you can power it up to make sure it works and then attach the amplifier cover using 4 more screws.

Step 7: Play Some Beats & Share It With All of Us!

Final Build

I don’t know about you but I was very excited when I built the first prototype using the Bluetooth module and that was even before I created this 3D printed version. In my opinion, this is definitely a very exciting build for anyone who wants to learn more about electronics. I hope everything worked together wonderfully and that you will continue building DIY projects like these.

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Categories: DIY Projects