Fine Little Sound Brooch

Take mp3 sounds in a brooch with you where ever you are. Well, almost everyone has a flashing LED sticker nowadays. But a pin with which you can take your favourite or most useful sounds with you? That's only available here.

Do you remember the Starfleet pins from Star Trek? Now you can make something like that too. I made it with some music and a greeting.

No programming required! (Just a little soldering and design skills)

Easy to make for everyone.

DFPlayer mini (I've found a cheap source: AZ-Delivery)

Micro SD card

piezo plate as speaker

LiPo battery 3.7V /180 mA or cell batteries

small metal box (of skin cream, mint drops etc)

slide switch

micro button

2 tiny strong magnets

The electronics are very simple. There is no need to program, the DFPlayer mini already has everything on board. According to the manufacturer, the small unit runs on 3.2-5.0 volts. If you have enough space in the housing, you can also use button cells as a power source, but they are more difficult to connect.

Preparation:

Usually the Player is delivered with pins already soldered. These must first be removed with the soldering iron to save space.

Soldering:

Just follow the plan when soldering. You do not have to pay attention to the polarity of the piezo element. Leave enough cable for the speaker, switches and power connection.

Actually, we only need one push button between IO2 and GND to switch to the next mp3 file. You can also solder another push button to IO1 and GND, with which you can go back in the file list.

Further it says about the two connections in the data sheet:

"IO 1: Short press to play previous (long press to decrease volume).

IO 2: Short press to play next (long press to increase volume)."

With both switches you have a fully functional mp3 player!

A metal box of skin cream or mints is best suited as a cabinet because it makes a good resonating body for our speaker. But thicker plastic or wood should also work.

Tape the piezo element tightly to the front of the brooch from the inside.

Insulate the inside of the box with tape to avoid short circuits. Drill/cut/file holes for the two switches in the housing.

Carefully glue the switches in the desired position. Hot glue or superglue are suitable. Make sure that the switches do not stick!

Almost finished!

Now you can paint, stick on, varnish, glue on with glitter, ...

With a 3D printer, you can certainly create many more shapes and also print smaller matching housings.

Copy mp3 files of your choice to the SD card and insert it in DFPlayer. Make sure that the files themselves have been saved with high volume.

Now our two magnets come into play. A magnet is attached to the inside at a suitable place on the back, again with hot glue or superglue. Once the glue has set, the brooch can be attached to the pullover or jacket with the second magnet.

Done!

In the same way, you can now attach the pin to any magnetic surface and leave a voice message: Car, front door, fridge, ...

Play it!

Pressing the button plays an mp3 file and stops at the end. The next time you press the button, the player jumps to the next track.

A word about the battery and its connection::

I made a plug-in connection with Dupont pins. You'll find a good tutorial here:

https://www.instructables.com/Make-a-Good-Dupont-P...

You can now disconnect the battery, charge it with a LiPo charger and then reinsert it.