Several years ago it was common for portable speakers to have 3.5mm jack and to be powered by AA batteries. By today's standards, it's a bit outdated especially the battery since every gadget nowadays has a rechargeable battery. The audio jack is still relevant but for how long?
I took it upon myself to upcycle such a speaker and make it a bit more 2018 compatible. These steps can, of course, can be applied to almost any speaker. But you may have to scale some of the components. Specifically the amplifier.
For a bit more details and fun, you can also check out the video :)
Step 1: Parts
- Bluetooth receiver (ST159_V3 on PCB)
- Amplifier (may not be necessary)
- Battery - any Li-po battery. The higher the capacity the better. At least 300mAh.
- Battery charger - TP4506
Depending on your speaker you might be able to use the built-in amplifier or get another one. The amplifier listed Should work for most speakers and it's the one I used but you can also get something beefier if necessary. This one is a more complete package with charging circuit but there are also some with BT receiver built-in. It's really just matter of what's the best for you.
Step 2: Disassembly
First of all, I'd suggest testing the speaker because you might end up troubleshooting problem that was there from the beginning. If it works you can take it apart and I assume that's not a problem for you. Next, gut the insides. Not everything though. If you're planning on using the original amp, keep it. Some other things to spare would be the board holding buttons or some sort of interface. You speaker may not have any. Another thing to look for is the audio jack if you want to keep it don't throw the board away. Everything else can go to trash. Battery compartment taking up most of the space -> trash. But keep the doors so that it can still look neat from the outside :) My battery compartment was decapitated with a hacksaw. It was a noble sacrifice for bright and wireless future :D
Step 3: Buttons and LEDs
Bluetooth speakers usually have buttons so our's will have too. Well, at least mine will. My particular speaker had USB input for USB sticks that's why there are six buttons and a couple of LEDs. But that's rather an odd design. The vast majority of these speakers had just an on/off switch. So for all of you, sadly you'll have to hack a single button somewhere in there. Or you can wire it up the on/off switch I really don't care. The single button is necessary to boot up the receiver. The other buttons are just for convenience so feel free to exclude them.
I've included wiring diagram and if you are using the same receiver as I am, you're in luck because there are convenient test points for pretty much each connection. It's almost as if it was meant to be modded. Don't forget to remove the battery from the Bluetooth receiver before soldering anything.
The LEDs are just for convenience too but why not wire them, Especially if you have room for them. The soldering on these might be a bit challenging and be very careful around the antenna as it doesn't have any solder mask.
Step 4: Wiring
With the buttons and LEDs working it's time to put it all together. Once again I've made a diagram which I'm sure you'll be able to follow. You might also connect the audio input to the original jack if you want. The on/off switch might not be applicable for your particular speaker. Please, when testing it for the first time do it with bench lab power supply. Don't just connect the Li-po battery. Bad things might happen.
If you followed my instructions and you were able to adapt them for your own speaker, congrats you now have your very own BT speaker. Not only is it yours but YOU MADE IT *clapping*. And if it doesn't work, well it never does on the first time :D That shouldn't stop you.