In this tutorial, I am going to show you how to build your own Bluetooth speaker system for fairly cheap. Between the time, effort and parts it might be simpler and cheaper to just buy one, but I’m guessing… no… hoping, that if you clicked on a DIY article you are the type of person that understands the value of doing these types of projects. From learning about Lithium battery charge and protection circuits and voltage step-up booster boards to the gratification of having started and finished something that you can use every day. Plus, what a conversation starter!
Now there are plenty of these types of projects floating around on the web. I figured we could spice this project up by making a battery pack that is detachable so it can be used to charge your cell phone or anything else that needs 5V. You can also power the Bluetooth chip via your cellphone’s USB charger too. Versatility is the name of the game.
Below is a list of the parts I used. However, feel free to go bigger and more powerful when you are choosing your Bluetooth board. Just make sure to buy proper speakers for the chip you choose.
NOTE: You can go bigger if you are feeling ambitious. Just make sure the output of the board matches your speakers and the power input matches your booster’s output. If you go too big though, you will want different batteries.
NOTE: The board mentioned above can push 4 or 8 ohms.
NOTE: This was for my design. I need to extend the Micro USB port of the Bluetooth board to fit in my speaker box. If you play around with your box’s design you might be able to skip this.
NOTE: The larger the mAh the longer your batteries will last without needing to be recharged.
Note: They make these with a Micro USB which might be a better option considering the prevalence of micro over mini chords these days. I just happen to have one with a MINI port laying around. If you decide to go with the MINI configuration you will need the right USB.
NOTE: Any DC-DC booster will work as long as it boosts up to 5V 2A.
NOTE: It should be made of wood so as to not short any circuits. It should have a lid (really helps with the low-end frequencies). Keep in mind that you will need to design your own layout and drill you holes.
This is incredibly easy. You just need to connect your speakers to the speaker jacks on the board and get a 5V power source to the micro USB port. I suggest testing the chip using alligator clips and jumper wires before you start your soldering and installation.
Once it is time to solder, it would be best to know the layout of your speaker box before you start, that way you can make the wires the correct length. I always leave them a bit long at first just to be sure. Flip the Bluetooth chip over and solder the breakout board (if needed). The VCC of the breakout will go to the 5V of the Bluetooth chip and the grounds of each will need to be connected.
Then you need to wire up the speakers. I suggest just soldering the wires to the Bluetooth board until your speakers are mounted in the box. Then solder the wires to the speakers. Make sure your wires are long enough to make it!
As you can see in the picture below, the wires are pretty much the perfect length. This cuts down on clutter, which is bad in small spaces. You might also notice that the Bluetooth board is mounted via its 3mm mounting holes. The breakout board is also featured. I just used hot glue to attach it to the inner wall of the box, though it too has mounting holes, if preferred.
Before moving on to the power source, I suggest testing the board and speakers again with the cell phone USB power supply.
First, you will want your batteries connected in parallel. That means the positive leads of each connected to each other and the same for the negative leads. It is best to do this via spot welding and a nickel slab, but sometimes you don’t have the equipment. I didn’t. So, I soldered them together. You need to do this as quickly as possible because the heat damages the batteries.
First, take a small hand saw blade or rough sand paper and make grooves on all the terminals which the solder can grab hold of. Then make sure your soldering gun is really hot. Then do it. Do it as quickly as possible and get it right on the first shot to minimize damage to the batteries. No pressure.
We need to wire up most of the rest of the materials. Solder the negative wire from the batteries to the B- on the TP4056 board. Do the same for the positive wire form the batteries to the B+.
Go from the OUT+ on the TP4056 board to the middle pin of the switch. Then from one of the outer pins of that switch to the VIN+ (voltage in positive) of the MT3608 board.
The OUT- of the TP4056 board goes directly to the VIN- of the MT3608 board.
It should look like this.
At this point we need to hook up a multimeter to the MT3608 board’s VOUT+ and VOUT- so we can adjust the output voltage to 5V.
To do that, you need to screw the board’s voltage adjuster in or out. The adjuster screw is highlighted in the picture below by a red box. You will probably need a flathead precision screw driver.
Once the voltage is a proper 5V you need to solder one last thing. You need to solder the USB Socket to the VOUT+ and VOUT- of the MT3608 board.
If you are looking at the socket the positive pin is the furthest left and the negative is furthest right.
When you are done, the entire battery pack should look like this.
I went ahead and wrapped mine up a little tighter, because as I said I wanted it to be a portable rechargeable cell phone charger on occasion. You don’t have to do it this way. You can just glue the components in your box if you want it to be more permanent.
All that’s left to do is connect the battery pack to the Bluetooth board. Then pair your Bluetooth ready device and play some tunes!!
Be careful not to push the Bluetooth board too much from your phone or computer’s volume control. I fried my first one that way.
Good luck. Stay safe. And, we’ll see you for the next project!