So the first thing I did was ... well of course order a cassette player.

I received one that also came with a cassette in it, lucky me.

I started dissembling the cassette player and reduce it to the bare minimum I needed to have the reading head still in working condition. 

That was the easy part. Turns out, there is basically no electronics in a cassette player, but the mechanics are just beyond genius. Back in the day there was so much ingenuity behind a lot of hardware to make up for the lack of advanced electronics. 

My brain already started over engineering the Tape Organ but when I started reverse engineering the PCB I stopped myself and instead try to use what I already had. So I screwed everything to a piece of plastic, so it would not slip around.

I then listened to the cassette. It was some kids music and ... most of it was pretty awful. I can fully understand why the previous owner didn't want to have it anymore. But one of the songs had some nice background drone in the intro. I cut out one single note of this drone and glued it to a 3D printed wheel.

I then arranged everything such that the reader touches the wheel and could ... well... do its job. 

Before I started coding the micro controller I wanted to make sure everything worked and I am glad I did because... no it didn't. When I spun everything up what I got did not even remotely sound like what was supposed to come out of the tape. 

I am not yet sure if my guess is correct, but I think having the tape glued to a wheel and have this wheel press against the reader does not produce the right sound. So I will now have to built something that uses loose tape without a wheel as it normally does in a cassette player anyways. 

So, back to the drawing board.