Love me some anachronism stew.

I feel like this could work using a tiny generator attached to the drive's motorized wheel, but that's probably too complex to be cost-effective for something like this unfortunately.

I think they might use AAAs

Down to you if that's worse or better.

Also buying a whole-ass new car stereo (+ installation) is much more expensive than a bluetooth adaptor from China

So if you're driving an ancient car out of necessity rather than for the aesthetic, this can help you get music into it.

F'course

Most cars from the age of tapes nowadays are relics. "Old cars" in the range that poor people drive out of necessity are from the CD age instead.

adjusts 🤓 glasses

So a cassette tape works by using electromagnetism. Ferric Oxide (AKA, literally rust powder) has a property that if exposed to a magnetic field, it will create a weak version of that magnetic field within itself

So the record head of a tape machine is an electromagnet that changes its field based on the actual audio signal, translating audio frequencies directly to magnetic directions and strengths, while the read head is a passive electromagnetic coil that picks up that weak magnetic field on the rust-coated plastic tape while a small motor runs the tape past it and emits it as a soundwave.

The tape adapter skips 90% of these steps —

— It just has an electromagnetic coil of its own, positioned so it lines up with the play head, and when you feed it an audio signal, that audio signal gets directly translated to a magnetic field just by running it through the coil. The tape deck picks it up and doesn't even realise there is no tape running through