This generator was made for a physics project and heavily inspired by Tom Stanton's generator (check his yt video on his 2nd channel for more details, here:

Printed with 0.4mm nozzle and 0.2mm layers

Notes:

You'll need some small rectangular magnets for this generator (64 x 10mm x 5mm x 2mm magnets, you can find them here: https://www.aliexpress.com/item/1005001614564310.html)

You'll also need a coil of 0.2mm copper wires (I bought 100m), which can be found here: https://www.aliexpress.com/item/1005003419270657.html?spm=a2g0o.order_list.order_list_main.16.4e3e1802M5wFNJ

You'll also need some super glue to stick the rods in place (print all rods horizontally for max strength

When making the coils just remember to use a lighter to burn off the enamel at the ends of the coils (or else it won't conduct)

In my generator I only printed 2 shells and 2 gears (resulting in a 1:25 gear ratio) and rotated it at 80 rpm with a motor. It gave about 3.8 peak mv per loop or 2.68mv AC per loop. With 300 loops it generated 0.822V AC.

Each loop can only hold 100 loops max (800 total max)

I wouldn't recommend going more than a 1:25 gear ratio since the torque needed to rotate would become extremely high

When putting the coils into the coil holder alternate the coil direction for each coil next to each other so the current generated is in the same direction, also do this for every 2 sets of magnets so that it alternates magnetic field direction