DC electric generator
https://www.youtube.com/watch?v=bfUWNGMjkrY
Output : DC
The generator contains a fidget spinner with iron insertions, 3 neodymium magnets ( discs), a coil iron less, glue ( for plastic) a reed switch and a led. The reed switch is the key component, without it the output of the generator it will be Ac.
more details : http://sciencetoolbar.com/new-science-projects-dc-generator/ (http://sciencetoolbar.com/new-science-projects-dc-generator/)