Bicycle Power adaptor for Freerunner

Helge Hafting helge.hafting at
Tue Feb 17 18:55:13 CET 2009

Alexander Mueller wrote:
> Hey all,
> is anybody out there who is using the FR on longer trips for navigation 
> and/or geocaching? How did you solve the power problem?
> I would love to have an adapter from my hub generator for the 
> Freerunner. Should not be too difficult. Something to convert AC to DC 
> and then maybe some switching thing to getthe right voltage (DC/DC 
> converter or what).

AC to DC is easy. 4 diodes, or a bridge rectifier. And then a big 
capacitor to smooth out the DC thus generated. According to the hw list, 
you need to ensure something between 4V and 5V for the freerunner. Not 
above 5V, and under 4V can apparently cause trouble too except for 0V.

There are voltage regulator chips that can be used for providing
5V. A zener diode can also prevent too high voltage, but the simplest 
way of using it will turn your generator into a brake as it simply 
wastes any excess electricity.

Helge Hafting

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