Introduction: The Restoration of a Music Box ... Electronically

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The idea to participate in the 'Trash to Treasure' contest came from an older project of mine, a musical box with a ballerina (or princess) singing either old Christmas songs or classical lullabies (Brahms, Mozart...). The wooden box was made in my brother-in-law's shop, I came with the electronic part and the mechanical part. Below you can see a photo collage and a video of the operation. The electronic part was made up of a mini mp3 player that plays songs from an SD card and an arduino mini that controls the mechanical part consisting of a stepper motor with its driver. On the sides of the box there were the play/pause next/previous track and volume up/down buttons.

So I started looking for an old wooden jewelry box suitable for transforming into an electronic musical box. I found the box that is in the first picture and I was sure it was a good choice but when I found the second one ... a small box, made in the 50-60s, in a very good condition but having the defective and irreparable musical mechanism it has become my favorite. I will show you in this article how I made an electronic music box from an old mechanical music box. This little box can play any desired melody but preserving the unmistakable feeling of the 19th century.

It is true that commercial offers of such electronic modules for music boxes have already appeared but their price is relatively high. And of course, let's not forget about the satisfaction you have when you make something great with your own hands :)

If you find this project useful you can vote for it at the 'Trash to Treasure' contest.

Step 1: Tearing Down the Inside of the Box and Removing the Mechanism

The box was covered on the inside with a velvet-like material (felt). In the third photo you can see the wire that triggered the music box mechanism. This mechanism was hidden with a help of a wooden cover that was not fixed to the walls of the box. I removed it, then, with a cutter, I separated the felt from the walls of the box, which turned out to be some pieces of cardboard to which the material was bonded. With a help of a screwdriver I removed the mechanism and I ended up with the empty box that was ready to receive the new electronics inside.

Step 2: Electronics

Parts:

  • 2200 mAh power bank;
  • GPD2846A MP3 Board;
  • mini speakers (23mm diameter);
  • USB A Male Connector - Solder Type;
  • micro limit switch (NC);
  • microSD card;
  • (optional) - push button (micro switch).

I have chosen the power bank (2200 mAh) taking into account both its size and the power consumption of the mp3 decoder module. At average volume and with the two mini speakers it consumes about 80 milliamperes. So with a 100% loaded power bank our installation should work theoretically 22 hours continuously (under 3.3v the decoder module can not work anymore).

I have connected the mini speakers in parallel because they have 8 ohm and 0.5 W , and the audio amplifier of the mp3 decoder has a recommended output of 4 ohm maximum 3 watts speaker.

The limit switch has its contacts normally closed so that when the box cover is opened, the limit switch will have the contacts closed and the mp3 decoder will be powered. Optionally, two buttons for previous/next track and volume up/down can be mounted.

The card I'm using has a 2GB capacity and is more than enough for the song (or a few songs) it will contain.

Step 3: What Music Should You Upload to the SD Card

There are a lot of options...

A quick tutorial...

I used for this music box a midi file for a composition of Ion Ivanovici - Anniversary Song (Waves of the Danube) a famous Romanian tune.

  • import the midi file in LMMS - remove all automation tracks
  • ...optional... double-click to track (the green area with notes) to open the piano roll, select al notes (ctrl+A), click to a note and drag to modify the notes velocity to be the same to all notes (a music box is not capable of volume modifications)
  • hide the piano roll (F7), open the instrument plugins window and drag the 'VeSTige' plugin (VST instruments host)
  • load the M-Box plugin (click the green folder icon in VeSTige plugin window and find the downloaded M-Box.dll file), wait for the VSTi plugin to be loaded (the plugin's GUI will show)
  • now you can hear the tune and make modifications in the plugin settings to a sound that you like (I attached a file with no modifications at all, there is also the tune I have used in the introductory video).
  • I attached another tune made with the help of this tutorial, the beautiful waltz 'Blue Danube' by Johann Strauss.

Attachments

Step 4: Putting All Together

First, I had to remake the interior felt lining as it was in the beginning. I used some pretty stiff cardboard and some felt (2mm thick). As you can see in the pictures, the remake came out pretty well. Next, I made a box to accommodate the electronics with a 4mm plywood. I drilled some 2mm holes in the box where the speakers will be placed with the help of a pattern. Then, I put the parts in place, made the soldering and hot glued everything. I carefully placed the micro switch as the trigger made from a paper clip must press gently and precisely onto it. After everything was in place I covered the plywood box with red felt and pushed the box in place. The box can be removed easily, there is nothing to hold it, but it remains because it is little bit forced in place. You can watch all these steps, checking the pictures above.

I hope you liked my project, feel free to comment or ask about it, I will try my best to answer your questions.

Trash to Treasure

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Trash to Treasure