Mp3 Music Player

An mp3 player I made for a school project. There is a speakar built inside and the buttons allow for volume control and skipping to a next song.

Wiring & Coding

Components Needed:

Arduino Uno

DFPlayer Mini

Micro SD card (formatted as FAT32, with MP3 files named 001.mp3, 002.mp3, etc.)

Speaker (4Ω or 8Ω)

3x Push buttons (Play/Next, Volume Up, Volume Down)

1x 1000µF capacitor (optional, for power stability)

Jumper wires (I used around 15, but get some spares)

Breadboard (optional for testing)

For the casing (design by fasaxc)

5mm thin MDF, Multiplex or some other type of wood (atleast 30 x 35 cm, but i advise on getting a larger plank of wood so you can afford making mistakes in the laser cutter)

Tools

Glue or screws (to hold together the casing)

Laser cutter (i used one at my school)

Soldering Kit (optional)

My original idea for this project was to create a working replica of the radio from the game Portal. I was actually pretty far in the proces of making it before altering the idea.

I found a 3D model online and modified it in Blender to make it suitable for 3D printing. However, when I was at the makerspace doing test runs I realized that the design would take too much time to print. Because of this, I decided to adjust my concept and move away from the Portal theme. It may have been too ambitious for my first arduino project. I setteled on making a simple mp3 player in a wooden case, this seemed like a more suitable beginner project.

Since I’m not the best of prorgrammers I decided to make things simple for myself by breaking the project into smaller, manageable steps instead of attempting everything at once. My first step was to connect the DFPlayer Mini to the Arduino and a small speaker.

For this I used the following schematic made by Indrek Luuk as a reference:

https://circuitjournal.com/how-to-use-the-dfplayer-mini-mp3-module-with-an-arduino

I’ve layed down the wiring instructions down here.

DFPlayer Mini to Arduino:

1. VCC → 5V (or external 5V power supply for better performance)
2. GND → GND
3. TX → Arduino Pin 10
4. RX → Arduino Pin 11 (via a 1kΩ resistor)
5. SPK1 → Speaker (+)
6. SPK2 → Speaker (-)

Now I could insert my sd card and the arduino will play the first song on the card. (When you upload your MP3 files to the sd card, make sure they are formatted as FAT32, and named 001.mp3, 002.mp3, etc. That way you won’t get any issues)

Now for the volume and play buttons. Originally i had planned to use a potentiometer to control the volume of the songs, however because of stability issues I decided to get rid of the potentiometer and replace it with two buttons, one for volume up and one for volume down. This worked much better.

Instructions for Volume & play Buttons:

1. Connect one button to Digital Pin 3 for Volume Up.
2. Connect another button to Digital Pin 4 for Volume Down.
3. Connect a final button to Digital pin 2 for play/next
4. Connect the other leg of each button to GND.

Coding

For the coding it is important to know that you'll need the DFPlayer Mini library to control the module. You can Install it through Arduino IDE:

1. Go to Tools > Manage Libraries, then search for and install DFPlayer Mini Mp3 by DFRobot.

The volume of the speaker can be adjusted within a set range of 0 to 30. I set my inital volume at a level of 20. While coding I made heavy use of Serial.print() to debug track numbers and volume adjustments, which helped track errors. One issue I face While prototyping was that the volume adjustments caused delays in playback. This was due to rapid polling of button states, which led to multiple triggers from a single button press. I managed to solve this by adding debounce delays and ensuring volume changes were processed at a controlled rate.

Lastly I added a bit of code that makes sure the song Automatically restarts at track 1 after reaching the last track.

My final sketch file can be found here:

For the casing of the music player, I used an existing design made by fasaxc:

https://www.instructables.com/Laser-cut-Arduino-radio-enclosure/

I went to my local hardware store and asked if they had scrap wood at the sawmill. I managed to get a 4mm thinn plank plywood for free, however i would later find out this was not the best of qualities..

I used the lasermachines from the makerspace at my school. I have never worked with these kinds of machines before, I struggled a bit with getting the size of the files correct in the software. Luckily, the staff member at the makerspace was very open to assist me.

We ran some small tests to see how the material would react to different laser speed and power settings. Despite these tests, the final result wasn’t perfect. The laser lens desperately needed cleaning, which led to some areas not being fully cut through, requiring me to finish cutting them out with a utility knife. Additionally, the wood quality was poor—likely why I got it for free. To refine the pieces, I used sandpaper to smooth out rough edges and remove sharp splinters

The next part of this project was soldering since this was a requirement for my schools course. For this I bought a small a soldering kit online:

https://www.bol.com/nl/nl/p/soldeerset-precision-soldeerboutkit-60w-200-450-c-tin-extractor/9300000171101586/?referrer=socialshare_pdp_www

This was my first time soldering ever and it took me a while to understand ho wit works. A lot of my solders turned out quite messy. Thankfully I had a lot of plates and wires I could test with. There are plenty of tutorials to be found on youtube that will help you understand the basics of soldering:

https://www.youtube.com/watch?v=6rmErwU5E-k&t=256s

I was afraid I would mess up the arduino and DFPlayer so late in the project. So I decided to leave them and only solder the necesairy parts of my project, the buttons and speaker.

Now came the most exciting part of the project—assembling it all.

For the casing is used glue to put the parts together. I left the roof of the case open so i could place the arduino and wiring inside. Now I had to connect the buttons to the outside of the case, however this turned out to be much harder than i thought.

One big mistake I made in this build was not modifying the original case design to include holes for buttons. I initially planned to drill them in at the end, but this turned out to be much harder than expected since the wood i used was quite flimsy. Instead, I used an awl to create the holes and then carefully enlarged them with a screwdriver. It was a clunky approach, but somehow, it worked.

I’m happy that the project is done and working, but it could definetly be improved.

For starters, adding a pause button would be great, along with a way to skip to the next or previous song. Another feature I had wanted to include—but couldn't due to time constraints—was a small LCD screen to display the song title.

Nonetheless this has been a very learnful experience for me, it was my first time working with both arduino, lasercutters and soldering. For future projects, I now know how important it is to always check the quality of your materials and to have spare parts so you can afford to make mistakes. For future projects I want to take a more structured approach and plan things ahead.