This rotor can be used for a wind turbine generator or water turbine.
The idea is to build coils with 20mm inner diameter and place them in a stator
so when the magnet passes over one coil to produce alternative current.
The design of the rotor help us deal with both sides of the magnet so we can make 2 stators with coils for our generator.
Below are some photos of how i made the rotor...
Coil voltage measurement test (coil dimensions: 20mm inner dia , 35mm outer , 250 turns 0.5mm wire dia)