DIY Bluetooth Speaker

In a world driven by innovation and creativity, why settle for ordinary? Presenting my latest DIY creation — a Bluetooth Speaker made entirely from cardboard! This isn't just a speaker; it's a statement — proof that even the simplest materials can be transformed into something powerful, practical, and downright impressive.

I created this project to push the limits of what's possible using sustainable, recyclable, and accessible materials. Cardboard is often overlooked, but it’s lightweight, easy to work with, cost-effective, and surprisingly good at acoustic insulation when used creatively. So, I decided to give it a whole new purpose — not just as packaging or a school craft supply, but as the heart of a modern tech build.

With a bit of engineering, some audio components, and a passion for making, I turned a plain sheet of cardboard into a stylish, fully functional Bluetooth speaker that doesn’t just sound good — it looks good too. Whether you're a student, a hobbyist, or just someone who loves building things from scratch, this project is a fun, eco-friendly, and rewarding challenge that blends electronics with design.

1. ON/OFF Switch
2. 4ohm 3w Spekar
3. Cardboard
4. Cutter
5. Soldering Wire
6. Helping Hands
7. Cello Tape
8. Fevicol
9. Glue Stick
10. Glue Gun
11. Double Sided Tape
12. 26 awg Silicon Wire
13. MH-M38 Amplifier Module
14. 18650 Battery Holder
15. TS80P Soldering Iron
16. Rechargable 18650 Battery

I began by carefully measuring the dimensions of all the components I planned to use: the two speakers, the on/off switch, and the USB port of the Bluetooth audio module.

Once I had the measurements, I transferred them onto the cardboard, marking the exact positions where each component would be mounted. This included neat cutouts for the two speaker units on the front panel, a dedicated space for the power switch, and an opening for the USB charging port of the module.

NOTE: Cardboard is forgiving, but clean cuts and accurate placements go a long way in giving your project that extra wow factor.

With all the measurements marked, Started by cutting out the required sections. Using a sharp utility knife (or craft cutter), I carefully followed the lines to make precise cuts for the speaker holes, the switch slot, and the USB port opening.

Clean and accurate cuts are crucial, especially when working with cardboard. They not only help the components fit snugly but also give the final product a neat and professional appearance. I took my time, applied gentle pressure, and used a metal ruler as a guide to keep the edges straight and smooth.

NOTE: while working with sharp knife, always take a look at safety first.

PRO TIP: Always place a cutting mat or a thick surface beneath the cardboard to protect your workspace and ensure cleaner cuts.

I began shaping the structure by joining the cardboard panels using cello tape. This helped me temporarily hold everything together and check the alignment before making it permanent.

Once I was satisfied with the overall shape and fit, I secured the joints using Fevicol (Glue) for a stronger and long-lasting bond. The speaker enclosure started to take form — sturdy, neat, and surprisingly solid for a cardboard build!

I intentionally left the top panel open at this stage. Since all the internal wiring and component placement would happen next, keeping the top accessible made things easier.

Now it was time to install the speakers! I carefully placed each speaker into its designated cutout on the top panel that I had previously marked and prepared.

Since Fevicol isn’t suitable for attaching electronic components like speakers, I used a hot glue stick for a strong and quick bond. However, I was extremely cautious — applying only a small amount around the edges. Too much heat or glue in the wrong spot could damage the speaker, so I worked slowly and precisely.

Once the speakers were firmly in place, I connected the wires with JST connectors, making the setup completely plug-and-play.

I carefully inserted the switch into the cutout I had made earlier on the side panel of the cardboard structure. To ensure it stayed firmly in place, I used a hot glue gun, applying just enough glue from the inside to hold it securely without creating a mess.

Placing the switch on the side panel made it easily accessible without interfering with the front design, giving the speaker a clean and functional layout.

Now it was time to install the most important component of the entire project — the MH-M38 Bluetooth Audio Module. This tiny yet powerful module is what brings wireless audio to life in this cardboard speaker.

I mounted the module on the side panel, right next to the power switch, for a compact and organized layout. To fix it in place, I used double-sided tape, which provided a clean, secure, and non-permanent solution — perfect for delicate electronics like this.

I began by mounting the battery holder inside the cardboard structure using double-sided tape. This method provided a firm grip without the mess of glue and allowed for easy repositioning if needed. I placed it in a way that kept the internal layout neat and prevented any strain on the wires.

Once the holder was securely in place, I carefully inserted the battery into it, making sure the polarity was correct and the connection snug. A firm and secure battery connection ensures smooth and uninterrupted power flow to the Bluetooth module and speakers.

Since I don’t currently have a laptop to draw a circuit diagram using Fritzing, I’ll explain the connections clearly in text so anyone can follow along with ease.

Speakers to MH-M38 Module: Each speaker has two wires positive (+) and negative (−). I connected the left speaker’s wires to the L+ and L− terminals on the MH-M38 module and the right speaker’s wires were connected to the R+ and R− terminals.

Power Connection: I used a battery holder with a 3.7V Li-ion battery. The positive wire (+) from the battery holder goes to the VCC or 5V input of the MH-M38 module (depending on your module version — mine supports 3.7–5V) and the negative wire (−) goes to the GND of the module.

Switch Connection: The switch is placed in-line with the positive wire from the battery holder before it reaches the Bluetooth module. This allows the switch to control the power to the module — turning the speaker ON or OFF easily.

With all the wiring done and components in place, it was finally time to close up the speaker and complete the build.

I carefully positioned the top panel, which holds the speakers, onto the enclosure. Since this was the final step and I wanted a strong, lasting hold, I used Fevicol to glue the top panel in place.

I applied the glue evenly along the edges, then gently pressed the panel down and held it for a few seconds to ensure a snug fit. After that, I let it dry properly for a firm bond.

With everything assembled and the top panel sealed, it was time to test the speaker and experience the result of all the hard work!

Before testing, I made sure to charge the battery using a Micro USB cable. One of the great features of the MH-M38 Bluetooth module is that it supports built-in battery charging, so there's no need for an external charger — just plug it in, and it starts charging right away.

Once charged, I powered on the speaker using the switch on the side panel. A small LED indicator on the MH-M38 module confirmed that the power was on. Then, I grabbed my smartphone, turned on Bluetooth, and paired it with the “MH-M38” device. The connection was quick and seamless.

Finally, I played a song — and the sound came alive through the cardboard speaker! It was a satisfying moment to hear clear, wireless audio coming from something made entirely out of cardboard and creativity.

I chose cardboard for this project because it’s something we all have lying around. Whenever I order something online, it comes in a cardboard box. After gathering a few of them, I noticed they were piling up — especially one large box that seemed too good to throw away.

So I thought, why not recycle it into something useful and fun? And that’s how this DIY Bluetooth speaker came to life — a small demo of how we can turn everyday waste into something cool and functional.

I hope you enjoyed this project as much as I did building it! If you found it helpful or inspiring, please consider liking and following my Instructables profile. I’d love to hear your thoughts, suggestions, or ideas in the comments section below!