Homemade Mini Wireless Blue-tooth speaker

 

You’re away from home and you just wanna blast your favorite song before going out. But alas, all you have is these puny laptop speakers…

No more! Now you can build your very own portable speaker that puts any laptop or phone speakers to shame. The design is simple, with only a small amount of soldering required. Better yet, aside from the enclosure, all the necessary parts can be bought from one place!

Speaker V1

All you do is hit the on switch, pair via blue-tooth to your phone or tablet, then let the music flow!

Electronics

Here is the parts list for everything you’ll need to put together its electronic guts:

Here is the schematic for putting everything together:

Speaker V1 Schematic

 

You’ll need to do some basic soldering to hook everything up. For the bluetooth module, I just cut open the wires included in the kit and soldered to those, in case I wanted to unplug the module for using it in something else. However, if you’re feeling adventurous, you could unsolder the connectors, then solder the 5v and stereo out wires directly to the board to save on physical space. I lost the pinout for the mono audio amp, so be sure to read the document that comes with it to see the proper pin outs.

As always, be careful when soldering. I am not responsible for anything bad that happens to you.

At this point, with everything soldered together nice and tight, it should work. Put in some batteries, flip on the switch, and you should be able to pair with your phone via bluetooth. If it doesn’t work, check for shorts in your soldering. If all else fails, you may have overheated one or more of the components when soldering it together, in which case you need new parts.

Enclosure

If you are lucky enough to own or have access to a 3d-printer, then all you need to do is download the enclosure. If not, you could build your own enclosure out of wood or other materials.

You’ll find the solid works files, as well as .STL mesh files. I have a Makerbot Replicator. So, I use ReplicatorG to import the .STL files, export to gcode, then send it off to the printer! I printed using white PLA plastic with the default Replicator settings, using 100% fill, 1 shell, and no support. I found that ABS plastic warped too much to be usable.

After printing the parts, feed the battery clip through the hole in the middle section into the battery compartment. Place the switch snugly into the hole in the side of the middle section. Then, put together the top and middle sections. I used an old soldering iron to melt the two halves together. You can also use certain types of glue, or use a heat gun. After that, stuff the electronics into the top section through the speaker hole. It will be a VERY snug fit, and it took me some time to get everything in. You can glue the various components to secure them, but I didn’t bother. Put the speaker on top so that the screw holes line up. Then, screw it in using 4 small metal screws. Finally, plug in your battery to the clip on the bottom, and use 4 more metal screws to screw the battery lid to the enclosure.

All done!

Improvements

I am already hard at work on version 2.0! However, I had a few retrospective thoughts on how this version could be improved. Feel free to try these ideas if you’re up for some experimentation.

  • Use this audio amp instead of the one listed above. It’s twice as powerful while costing half as much and taking up much less space.
  • Use higher value resistors for the stereo to mono conversion. The 1K seem to saturate the sound when it’s near max volume. Better yet – buy a consumer stereo to mono adapter.
  • Use a filtering capacitor across the speaker terminals to eliminate some high frequency hissing and noise.
  • Use a piece of foam in the battery compartment to keep the battery from rattling around.
  • Don’t melt the two halves of the enclosure together. It doesn’t look that great.
  • Use black plastic instead of white for the enclosure. It would look way cooler.

Final Notes

That’s about it! I have no idea how long the battery lasts. I’m still on my very first set of 8 AA’s and it’s still going strong after 6+ hours of usage. I would estimate about 8 – 9 hours of playback at middle volume.

If you end up trying this and make any improvements or have any thoughts on the design, feel free to let me know!

Cheers.