In this instructable I am going to show you how to house a MP3 player in a cassette tape. I had the idea to build this quite some time ago, but while I was still waiting for the parts to arrive, instructable member lonesoulsurfer posted his version here.

So I decided to concentrate on other stuff and somehow forgot about it. After moving recently, the parts fell into my hands and decided to give this project an other shot, since my approach is quite different from lonesoulsurfers. My idea was to actually use the cassette tape wheels as buttons to select the songs and adjust the volume.

The cassette I used for this was broken and I decided to give it a new, more modern life.

Btw. I know that you can buy cassette MP3 players e.g. here or here, but I wanted to build one that looks completely like a normal cassette.

Step 1: What You Need

Materials:

Cassette (that is held together with screws)
Block USB MP3 Player (e.g. from amazon.com or a lot cheaper from ebay)
Glue (jb weld, faster setting 2 component glue)
Enameled copper wire (e.g. from amazon.com)
Two M3x20mm screws
Micro SD/TF card (max. 8GB)
Solder
4 miniature snap action switches (e.g. from digikey)
Shipping labels (if you would like to change the label)

Tools:

Soldering iron
Rework station (not a 100% necessary, but certainly helpful)
Sharp knife
Screw driver
Diamond file

Step 2: Take the MP3 Player Apart

Start by taking the MP3 player apart. The bottom can easily be lifted off with anything sharp. There is a single screw next to the SD card, holding the board in place. Unscrew it and take everything out of the shell.

Remove the sticker from the buttons and unsolder the battery. You will also have to remove the audio plug, the on/off switch and the micro USB jack. A rework station is certainly helpful in fulfilling this task. Make sure to keep all the unsoldered parts, you will need them later on.

Step 3: Preparing the Cassette

Take the cassette apart in order for it to house all the components. Afterwards you will have to create the openings for the headphone plug, the USB jack and the switch. I decided to place the opening for the audio plug at the side of the cassette, so that I would be able to carry it around in my trouser pocket and to use the two already existing holes at the top of the cassette for the other two components.

Step 4: Creating the Push Buttons

I decided to keep the magnetic tape, because removing it felt as if something was missing. Since I couldn't fit it in there entirely, I had to cut it to the correct size. To prevent the tape from unreeling, I used quick setting two component glue, as shown in the pictures. Before you do so, cut off an around 10 cm long piece, since you will need it later on.

Cut a small slot into the wheels and glue the screws into them (You don't have to cut the screw heads off, like I did). You can of course use any other type of pin, but I found that a M3 screw has the perfect size.

As you see in last step, the space is very restricted. You will have to cut some of the plastic from the wheels in order for them to fit (as shown in the pictures). Remember that you will have to move them later on, so make sure that you are able to do so. Afterwards glue the miniature snap action switches in place so that they can be operated by the pin. Connect them to the board, as shown in the pictures. If you have not worked with enameled copper wire before, don't worry it is quite easy to use. Simply use solder to burn the protective layer away. If you are still unsure, it is explained in this video.

Step 5: Assemble Everything

Solder everything back in place as shown in the picture. Make sure that the SD card fits and that everything moves fine. Use the JB weld to hold everything in place.

After the JB weld is set, glue the magnetic tape you prepared before back in place, as shown in the second picture. Make sure, that the wheel can sill be moved without any interference. Use the 10 cm piece of tape that you saved before and glue it to the two small wheels at the bottom of the cassette.

Screw the cassette back together and change the label, if you want to. Songs can by added with an USB cable, so you don't have to open the cassette every time.

I added a pdf of the label I made so that you can make your own Guardians of the Galaxy version. Upload the Guardians of the Galaxy: Awesome Mix Vol. 1 and you are ready to safe the universe.