CAD Render

 Toddler Music Box

This is a music box I made for my two toddlers (mostly my daughter). The function is very simple: When you turn it on and press the button it plays a tune. The volume can be controlled via one of the knobs, while the other knob selects what song to play. It is currently set to play the “ABC song” when the knob is to one side, or play “The Wheels on the Bus” (a big hit currently, we especially love the “Up and Down” verse).

Getting into technical detail, the box runs off an Arduino Micro. The switch controls the master power while the button is connected to one of the inputs. The song output goes to an audio amp IC. The volume knob is a current limiting potentiometer between the amp output and the speaker. The song selector is a potentiometer connected between gnd and 5v with the wiper on one of the analog pins.

Here are some more CAD views:

Here are some photos:

Interior View. (I made a couple revisions after this photo was taken.)

Control Panel. I do not recommend this filament, but my kids don’t seem to mind.

Closed

I am happy to say the box is a big hit. My daughter especially loves it.

Works for small hands.

I’m not sure what was happening here. I think she wanted to help me rebuild it, as she has seen me do with things a number of times.

Yes, I would like music at snacktime. Also, you can see in this photo a printed potentiometer knob that’s easier for small hands to control.

Plans for Future Revisions

I have many ideas about future design changes that I think would be fun (this is already gen 4 or 5). I may or may not ever get to these:

  • LEDs that light up with the music.

  • Making a handle you crank to make the music play, ala manual music boxes. I’ve tested out the circuitry and program for this with a motor that has an encoder installed and it works, although timing that is both variable and able to achieve a good sound will take some experimentation. I will problem make this after the novelty of this box has worn off.

  • Using a cheaper and smaller off-brand Arduino. Not having the pins sticking out the top would make it a bit smaller as well.

  • Adding an AUX jack in case she wants to use it for a dance party.

  • Making a device that plays mp3 files instead of just tunes (lists of notes and their durations). Like using the encoder above I’ll probably do this after the novelty of this box wears off.