Small Entertainment System

On the AliExpress site (and probably Banggood, eBay and other sites as well), there are a number of modules that claim to be capable of accepting music via Bluetooth, playing MP3 files on SD cards and USB sticks, FM Radio, Aux input and if that wasn't enough, some even come with an Infrared Remote Control. But the most interesting part is that many of these modules are less than $5. I purchased a few to try them out.

It should be noted, that some sort of amplifier is required. In my builds I used a TEA2025 IC wired as a mono bridge amplifier. My first design included a mixer to combine the left and right channels to feed into the amplifier section. However in later versions, I found it wasn't necessary and in later builds just used a couple of 1K resistors to isolate the channels.

Build 1 - Design

For the first build, I designed a case using OpenSCAD and 3D-printed it. I designed a PCB for the amplifier and made it using the Toner method.

Build 1 - Conclusion

This module performed as advertised. I had no problem pairing my phone using Bluetooth and was able to play my music from my phone. The SD Card and USB sticks worked well and played my albums sequentially even though they were in separate folders. The FM Radio worked surprisingly well considering I wasn't using an external aerial. The Scan button scans the FM band and then you just use the forward an back buttons to switch between the found stations. It does remember the last station you listened to. The Remote Control worked but it needs to be close to the unit. It can't handle much of an angle from the sensor either. You really need to be in front of the unit.

If there is a negative, it doesn't go back to the last mode it was when powering up. It scans the SD and USB slots first. If a card or USB stick is not present, it defaults to Bluetooth.

Build 2 - Design

There isn't much design in this build. I managed to grab a PC sound system on council pickup day that someone threw out. It contains a bass speaker and left and right satellite speakers. I cut a hole in the bass speaker case and mounted one of the modules. I wired the input of the amplifier to output of the module. The old input connection in the bass speaker box is wired to the AUX input. I also added a on/off switch on the front on the box.

The satellite speakers are mounted under a shelf that sits above my workbench. I used hard-drive magnets to fix them in place as I couldn't screw them to the shelf because they are designed to sit on a desktop.

Build 2 - Conclusion

This unit has become a permanent part of my workbench. It really works well and my second PC is plugged into the AUX port. My main PC can use Bluetooth to connect to the amplifier.

As far as its positives and negatives, it is same as Build 1. The IR remote needs to be almost directly in front of the sensor and can't be too far away.

Build 3 - Design

The smallest module of the bunch doesn't have a FM radio (even though some sites say it does) or Infrared Remote Control. I decided to incorporate this module into a Sad Robot chassis. The Sad Robot 1 kit came from MadebyA2. Unfortunately he doesn't seem to be selling the kits anymore. I designed a new top to hold a speaker, PCB and the MP3 player module.

Build 3 - Conclusion

Because the FM Radio and IR remote is probably the weakest part of these modules and since this module doesn't have either, it works pretty well perfectly. It is a bit hard to get the SD card in and out. I needed to use a screwdriver tip to push it in far enough.

Overall Conclusion

I haven't figured out what to do with the fourth module yet but I am sure I will find something for it in the future. These modules are great value and work really well. There are so many styles to choose from and they all basically work the same. I highly recommend them.