[OLPC India] [Community-news] OLPC News 2007-10-20

[Ajay Kumar]

Arjun,

After the initial excitement of the prospects, when I calculated the
power required, I was not sure of the feasibility, and started thinking
that you were playing some internal joke on the list. And played along
in the lighter vein. It was too late in the night and in the sleep
deprived state, my foot found my mouth.

Good stuff all the way, and cool approach. Please do sound me if you
need anything on the electrical system design. Finally some day my
electrical engineering UG might find an application. :) . I would still
recommend looking for an induction motor solution, because it is more
robust inherently. A brushless system. Plus DC--DC stabilizing circuits
tend to be a bit dodgy. Especially if you ever need to step up the voltage.

I am sure it could be used to power the school servers, and the wireless
network, if not the laptops. All the very best in your endeavor. :) And
please do keep us all posted on the progress.

Cheers,
Ajay





Arjun Sarwal wrote:
> Ajay,
>
> Thanks for sharing your thoughts.
>
> Our approach was to not look from a motor/dynamo etc. point of view.
> Our approach was to develop power solutions around locally available
> mechanisms.
> At the village (pilot site near Mumbai) we explored the ideas of using
> solar power (in Mumbai sunlight is not consistently strong) , running
> water (we couldn't find any local water bodies nearby), wind power (no
> wind in the that area), mounting small dynamos on bicycles (we found
> out that in that area bicycles aren't that common at all, esp in that
> village) ....but the village had an abundance of cattle - that were
> being used in the fields. So we decided to design something around that.
>
> Having  said that, the solution is of course not a one-for-all
> solution, but is an example of how locally available mechanisms can be
> leveraged  to charge the laptops. The mechanical and electrical design
> would be re-usable in a way that other driving mechanisms at other
> places could be used to drive a dynamo/alternator by following a
> similar design approach.
>
> We considered using a small motorcycle/moped engine , but that would
> lead to recurring costs of petrol/diesel for the villagers, hence we
> decided against it. Minimizing costs, is also an important factor for
> easy replicability , as you would agree.
>
>
> Thank you for your suggestions and interest , we appreciate them.
>
> Regards,
> Arjun
>
>
>
> -- 
> Arjun Sarwal ( arjun at laptop.org <mailto:arjun at laptop.org> )