Revisited: Bluetooth Speaker

20160804_172458 In the last little while or so, I found myself using the Bluetooth speaker I made last October. There were a few minor things that I wanted to address so I went ahead and made the modifications.

20160804_173243The main technical modification was adding an on/off switch to the power supply. I would have to keep plugging and unplugging the unit which got a bit annoying after a while having to do that almost daily whenever I wanted to use it. It was very easy to do since the electronics are completely accessible from the open underside. I simply cut the positive power line and soldered a switch in place.

20160804_175950The other modification was purely aesthetic. I removed the label and painted it all grey. My original choice was blue but I didn’t have that color paint. Either way, I think it looks good.

It’s always nice to revisit old projects with new techniques and materials. Stay tuned as I’ve revisited another project as well!


DIY Bluetooth Speaker!


After weeks of waiting, the parts I needed for a homemade Bluetooth speaker arrived. Pictured above are the PAM8403 amplifier board, Bluetooth module (USB powered with a 3.5mm audio jack), and a couple of 3-watt speakers. The power supply is a 5V 2A power supply I had laying around. All of the project materials amounts to roughly $13.

I got the inspiration from a couple of my favorite YouTubers — GreatScott and David Watts. They had much more polished finished products with a good quality speaker and cool enclosure… I had neither of those.

The project itself was simple enough: Break open the Bluetooth module, apply power to it, and then take the audio signals to the amplifier which would drive the speakers.


Here’s the Bluetooth module cracked open. My original intention was to remove the audio jack and USB plug to end up with a flat board, but the desoldering did not go well as I didn’t have any solder wick. After some failed tries with my desoldering pump, I ended up cutting off the edge of the board with the USB plug, and giving up on removing the audio jack. There were two copper pads near the USB plug that were labelled Vcc and Ground so I used them to apply power instead of bothering the with the pads of the USB plug.


Wiring it together did not go as simple as I thought it would either. I tried connecting wires directly from the pins of the audio jack to the amplifier board, but it didn’t work. The audio jack was still working with headphones, and the speakers worked faintly when connected directly to the audio jack. (The speakers arrived a bit banged up so I was worried they may have been broken.)

After some time troubleshooting, I ended up replacing the PAM amplifier board (I bought a few, exactly for situations like this) and spliced the included 3.5mm audio jack cable and used that to connect to the amplifier board. I was so happy to hear the power-on tone that the Bluetooth module makes!


After some playing around with it, I realized that there was only static coming out of one of the speakers so I chopped that one off. I’m not a audiophile by any means so I’m easily impressed… I was pleasantly surprised in the audio quality from these cheap speakers. Even with just one speaker, it can get pretty loud without sounding bad.


Time to put everything into an enclosure! This was my first time using foam board. If I didn’t use foam board, I’d still be using cardboard. Now that I’ve given it a chance, I can definitely see foam board being my go-to material for this sort of thing. My cuts are a little rough but I learned later on that using a new blade and/or cutting at an angle will give you cleaner cuts.

I used some needles to keep the foam board in place while I used hot glue everywhere.


Once I was finished putting it together, I printed out a simple nameplate for the speaker.

The Bluetooth module board has a blue LED that blinks rapidly when it isn’t connected, and once every 3 seconds when it is. Honestly, it wasn’t intentional, but my design with raised bottom, which was intentional, worked in the LED’s favor as it gives it a neat glow underneath the speaker. The nameplate originally had a note about how the rapid blinking meant it wasn’t connected, but my printer wasn’t having it…

So that’s it! It only took me half the day from start to finish and I am satisfied with the final product. I hope you’ll take this post as inspiration to whip up your own Bluetooth speaker!

Thanks for reading!

Animatronic Head project, now “The Box”

In my five project Project Lineup, I had an animatronic head project listed there. I want to move away from the usual roaming robots because I get tired with them too quickly. In the past, I’ve seen people make cool robot faces with LED matrix eyes and servos that moved it around to follow and interact with you. I wanted to try something like that.

The Shelf Lighting System project sort of drained me as I’m finding it hard to be creative. I ended up with this after 15 minutes:This is a crappy version of what I had in mind but still somewhat close, which made me even more unmotivated just looking at it. That’s why I made the change to “The Box”.

The main purpose of this project is to put to use all of the parts I currently have. The picture above shows them all: 2×16 blue LCD, RGB LED, 8-ohm speaker, photoresistor, sound sensor, temperature/humidity sensor, and a Real Time Clock. The animatronic head was going to have these parts anyway, but taking away the servos and unique form factor, compared to a box, will make things easier for me.

The kicker for this project is that it will have an accompanying Visual Basic Windows program, although it won’t be necessary to use it all the time. I’ll have info on that when I get around to starting it.

A quick note about the temperature/humidity sensor… I just found out that the prototyping PCB I used actually has a second layer that connects pads on the board. It’s hidden under the silkscreen so I didn’t know until now. It looks like there’s a shorted connection so I’m going to try and salvage the sensor and put it back on a board like the one used for the RTC.

I’ll begin testing each thing and then start combining it all together.