How to Build a Bluetooth Speaker for Under $10 Using Scrap Electronics

Introduction

Building your own Bluetooth speaker using spare parts and electronics you have lying around is a fun and inexpensive project that anyone can do. In this guide, I will walk you through step-by-step how to build a Bluetooth speaker for under $10 using scrap electronics and parts.

Gathering Materials and Tools

The great thing about this project is that you likely already have most, if not all, of the materials needed. Here's what you'll need:

Materials

Speaker driver - This is the main component that produces the sound. You can salvage one from an old speaker, radio, etc.
Amplifier - A small mono amplifier module like the PAM8403 is perfect. I had one leftover from another project.
Battery - A lithium ion battery pack or a few AA batteries will work. I used a spare USB power bank.
Wires - You'll need speaker wires to connect the amp to the driver. I salvaged hookup wire from an old project.
Housing - This can be anything from a plastic food container to a mint tin. I used an old tin.
On/off switch (optional) - A basic toggle switch. I had one in my parts drawer.
Bluetooth module (optional) - An audio Bluetooth module if you want wireless functionality. I had a spare one.

Tools

Soldering iron and solder
Wire strippers
Hot glue gun
Drill for making holes

Circuitry and Wiring

The wiring for this project is very straightforward. Here are the steps:

Connect the speaker driver to the speaker output pins on the amplifier board using speaker wire. Make sure to observe polarity.
Connect power to the amplifier board. I soldered wires from my battery pack to the power input pins.
Add a switch (optional) between the battery pack and amplifier to turn it on and off.
Connect a Bluetooth module (optional). I soldered the audio out pin to the amplifier input.

Use diagrams or photos to help illustrate the wiring. The key is connecting the amplifier output to the speaker driver input correctly using speaker wire. Powering the amp and connecting audio input like Bluetooth is fairly simple.

Constructing the Housing

The housing for the speaker can be anything you have on hand. I used a small tin box which worked perfectly. Here's how I put mine together:

I measured and drilled holes in the tin for the speaker driver, switch, and charging port. Use a drill bit slightly smaller than the part your are mounting.
I hot glued the speaker driver and switch in place aligning them with the holes.
The amplifier board was mounted to the inside wall of the tin using foam tape. This kept everything in place.
For a clean look, I soldered all connections instead of using breadboard jumper wires.

Finishing Touches

To complete the speaker:

Use hot glue or putty to seal any holes or gaps in the housing. This improves sound quality.
Decorate the housing if desired - I spray painted mine and added stickers. Get creative!
Consider adding rubber feet on the bottom to prevent sliding and improve vibration dampening.

And that's it! Now you have a custom Bluetooth speaker you can use anywhere. The total cost was under $10 since I used spare parts and salvaged materials.

Troubleshooting

If you complete the project but get no sound, here are some things to check:

Verify wiring between the amplifier and speaker - check connections and polarity.
Check power to the amplifier - Make sure battery is charged and connections are solid.
Test speaker and amp separately to isolate the issue.
If using Bluetooth, pair a device and verify the module is transmitting audio.
Check volume on audio source and amplifier.

With a bit of tweaking, you should be able to get it working! Building and troubleshooting is part of the fun.

Closing Thoughts

Constructing your own Bluetooth speaker is an enjoyable electronics project that can be done on the cheap. With scavenged parts and a spare amplifier module, you can build one for under $10. Not only is it inexpensive, but it's the perfect way to recycle old electronics and learn new skills along the way. So gather up those spare parts and start building!