Sunday, March 13, 2016

Portable Bluetooth Speakers (fin)

I finally invested in a $20 heat gun from Lowes. They're not only useful for bending acrylic sheet but also for desoldering SMD components:

You want to work on a surface that will not be damaged by heat. In this case I worked on some ceramic tiles and newspaper.

This was the outcome of the first bend (crack is from the failure last time).
Turn on the heat gun to full heat and run it up and down the line until the acrylics gets all floppy.
When it's malleable enough, you can bend it to the correct angle and hold until it sets.

Doing the second bend

All the bends are complete! we have a nice triangle.

I bought a huge sheet of faux leather for $10. I will be covering the frame in this so it looks sweg.

Mark out the surface area of the triangle. Leave extra room for folding.

This part isn't totally necessary, but it's good practice. You will want to line the inside of your speaker enclosure with some sort of dampening material so it doesn't vibrate and sound crappy.

I used some material from an air filter. Here I measured out how much I needed.

Cut holes for the speakers.
I secured the material in place with hot glue.

I didn't have a great method of securing the leather onto the surface. I used a combination of glue stick glue and hot glue to secure the leather in place.

Simply wrap the leather around the plastic casing.

The downside of using some sort of solid glue is that it leaves marks.
After you're done wrapping, cut out the holes that were there with a knife.

This  next part is an overview of the circuitry inside of the portable speakers.

I took apart a portable phone charger for the 5v power source. This power source was a bit small and couldn't provide sufficient power for max volume. You would want to take apart a battery back that has more than 1000mAh capacity.

I removed the USB socket from the board to save space.

Soldered wires to the aux female connector.

Soldering the aux plug to the PAM8403 amplifier.

Here, everything is connected.
  • Speakers connected to respective "left" and "right" outputs of the PAM8403 amplifier
  • TRS female connected to respective "left" and "right" inputs of the amplifier
  • Power source connected to switch, connected to the amplifier.

We almost forgot to add bluetooth!

I bought a USB powered bluetooth module for ~$5. These are extremely useful if you want to add bluetooth audio to your car.
We just need to take this apart, connect it to the speaker power, and connect the audio output in parallel to the existing plug.

I asked a friend to cut out the endcaps for this project. The outcome was beautiful.

After all the electronics were finished, I shoved everything into the speaker box and glued in the end caps.

I have the recharging circuit board poking out so I can charge it 

Suggestions for the future:

  • Use a 10,000mAH power source. with more power, your speakers will be louder, last longer, and have exceptional range for bluetooth
  • perhaps have a circuit board in the future so the inside isn't a messy nest of wires.

That's it for now! Hope you guys enjoyed.