Even Erichsen developed a 30W DIY electricity generator which you can 3d print name "The Beest".
The Beest is powered up by hand (or other mechanica source) via the series of gears: ‘1:2 + 1:4 + 1:3, so one turn rotates the rotor 24 times. The rotor is set up like a 3 phase axial flux generator, with three stators and six rotor plates with a total of 96 neodymium magnets.Very cool project, but full instructions are not released yet. If you have some knowledge of electric generators, you will be able to recreate this.
Here is the project description by the creator:
This is a working hand cranked power generator.
The rotor, in the picture, spins up to 1500 rpm, and produce about 30 watts.
I recommend building the rotor as seen in the fbx-file, for more power.
Needless to say – this is a huge print! Minimum 200+ hours....
On the hardware side you need 96 neodymium magnets (25mm diameter x 10mm),
about 1,3kg of enameled copper wire, preferably six steel plates, a pile of nuts & bolts, electronics - including an Arduino nano, display, bridge rectifier(s), diodes, capacitors, resistors, voltage regulators etc.
If you want to etch the PCB yourself, you will need a blank 160mm x 100mm copper board and your preferred chemicals.
Generator in action:
Thingiverse page with all the files:
There is also a much simpler 15W version at: http://www.thingiverse.com/thing:145186
Here is the Beest fully assembled: