A music box for the kids.
There are a number of certainly very nice music players for kids out there which allow them to place a little figurine on top to automatically start playing a tune or an audiobook. That's what I was aiming for, except fully customizable, and without the need to connect to wifis, clouds or the like.
We are travelers, so the system should work everywhere - my 2y/o already complains enough about Internet quality on overland trips - and ideally store more books on fewer figurines. I'm sure my kids would be able to use a regular USB stick, but hey, there's a 3D printer in the house.
I went for a simple USB mp3 player, a handful of adapters, some USB-C magnetic contacts to connect the figurines, and USB-C memory sticks (which are still only available with regular USB on the other side).
- Player: TECHNAXX 3545 MusicMan Soundstation
- Elebase USB C Female to USB Male adapter
- GARAS Type C Magnetic Adapter (aliexpress)
- Kingston DT microDuo 3C 32GB (you could probably find a cheaper one)
- and an angled USB adapter I had lying around.
The sound setup works nicely, and the figurines pop onto the contact with ease. The USB contact is slightly recessed, so that it should not get damaged from playing.
The player has a physical on/off switch, and auto-plays whenever a file is detected on USB. Disconnecting the magnetic contact stops the play, and resumes from the same position whenever reconnected. My angled contact was pointing the wrong way, so the display ends up being on the bottom, but until they can read that won't matter much. There are buttons to skip forward, back and adjust the volume, which I just had to mark clearly.
See https://www.thingiverse.com/thing:3493655 for some example figurines I printed, and https://www.thingiverse.com/thing:3493643 for the cartridge that holds the USB/storage components.
I printed the figurines in woodfill PLA, and the kids were happy to paint "their" music collection. :) Of course, multicolor is another option.
In a home setup, you probably want to use small storage units and a large number of figurines, so that the kids can easily identify the songs and audiobooks they want to hear. But since we are part time digital nomads, they get one figurine each in their hand luggage and we'll just have to cycle the selection now and then.