this is a prototype first step you should buy a good fidget spinner ( I used a cheap one 0.5 $ ) . you can use a capacitor. adding more coils itwill slow down ( it is about the load ) you can use a led will small consumption and you can wind a more sensitive coil.

I know it's a prototpe.. but it's the simple stuff like this I want to show my kids to get them into electronics :)

Thank you for sharing!

Could I add a capacitor to smoothen out the current supplied by the magnets and have the led burn longer? (can someone draw me a simple diagram?)

And would adding 2 more coils give me 3 times the power over time, or would the fidget spinner slow down a lot faster due to the coils absorbing the angular momentum through the magnetic field flux, making the whole idea stupid?

Awesome idea!