3d printed kinetic charger case

You can make a kinetic charger using your 3D printer and a little effort.
This allows you to charge your electronic gadgets here and now. Also, it would be a good gift for your favorite.
How it works:
http://www.slideshare.net/bulgakovatanya/elveet-kinetic-electric-power-charger
https://youtu.be/LHIOgC25BWc
Some details.
Inductor:
25x5x2.5mm NdFeB Magnet 20 pieces
https://www.indigoinstruments.com/magnets/rare_earth/
2 pieces Li-ion battery (any up to 3500mA)
https://goo.gl/QbeFSE
8 c