[Peripherals] Alternitive Power for Developing Countries

Thu May 8 10:08:22 EDT 2008

I've been thinking about power solutions for the XO for some time now and
I've been following this email thread with great interest. 

I have always thought that a spinning wheel type contraction would be
interesting to explore and it holds advantages over hand generation solution
because you can work and generate power at the same time.

However, when I imagined a classroom with 30+ of these machines in, with
children pedalling away that's when I because a little suspect.

Should we really expect children to generate the power for the XO?

Personally, I think the power requirements for the XO is too high for
children to charge them. Yes, I'm sure something can be created that
children could operate - but is this scalable and long term? Do we think
that children are going to want to do this everyday throughout their entire
education?

Regardless of if its realistic or not here are some approximate costs
(educated guesses);

    * Personal Solar: $20 per XO (Variable effectiveness and difficult for a
classroom environment)

    * Classroom Solar: $35 per XO (Assuming peak efficiency - Roof solar
with charge controllers and power distribution)

    * Classroom Wind: $15 per XO (Assuming peak efficiency - Wind Turbine
tower outside school - variable output - Wind power generates the cube of
velocity)

    * Hand Crank: $15 per XO 

    * Cow Power: $13.75 per XO (35A Alternator ($300) + Gearing ($150) +
Batt ($100) = $550 for 40 XO?) (How much does a cow cost to 'fuel'?)

    * Spinning Wheel: ???

Feel free to modify these numbers.

I think what is most important is to determine the sources of potential
energy in areas that need it, then design technology to utilise that.

Javier I think you have mentioned that both water, wind and sun are too
variable to design a cost effective system around. Can you think of energy
sources that are readily available in these areas that could be utilised?

You don't happen to have an abundance of zinc ore in Peru do you?

Kind regards,

Josh

==

Joshua Seal

josh at laptop.org

  _____  

From: peripherals-bounces at lists.laptop.org
[mailto:peripherals-bounces at lists.laptop.org] On Behalf Of
info at olpc-peru.info
Sent: 06 May 2008 18:55
To: arjunsarwal at gmail.com
Cc: Carla Gomez Monroy; peripherals at lists.laptop.org; Holden Bonwit
Subject: Re: [Peripherals] Alternitive Power for Developing Countries

Hello Arjun et al,

>* Cost of Alternators -- I agree they are expensive. Have you thought

about taking car alternators? 

You need to choose those alternators that have low RPM (low Revolutions Per
Minute).

>They give 12V and usually have built in

mechanisms for cut-off when the battery is fully charged, and also

would be easily available. 

Yes, easilty available.  In Peru that means that, but it doesnt mean that
they have a low cost.  The most popular car here is the Korean "Tico".  Is
everywhere, but... unlike we are... there is such demand that the alternator
(new one) cost US$300 each one.

It is not possible to think in a solution based on "second hand"
alternators... they work.. but how we will get 250,000 used alternators for
the 250,000 XOs that will be deployed in Peru ?  We need to develop
prototype, pilots that can be "sourced" in a secure, stable, confident way.
Wars have been lost due to the failure on the supplies chain.

>In India I've found car alternators to cost

~$100. They give about 35A output.

Maybe we will need to import them.  But... who will finance this ? We can do
the pilot/experiment/test/initial design.  But... what then?

>... I have come to realize

that it is very difficult for a human to provide the mechanical power

needed to charge an XO, whatever they may use - legs/hands etc. This

was one of the reasons why we fundamentally wanted animals to drive

our solution and not be human powered.

That is because we are thinking in using ANY alternator. Normal car
alternators (like a Toyota) need 3,000 RPM.  Then you need to "pedal" (on
the bike) very fast and very steady to reach those RPM that the alternator
needs to start to generate energy.  IF you use a LOW RMP alternator then you
don't need so much mechanical movement.  There are alternators (here in
Peru) that works at very low RPM, just 200 RMP and they are generating huge
energy, they are used for some mining equipment and they cost around US$800
each.  So, technically is possible to "break" the RMP barrier, but then
money is an "impossible" wall to climb.

There are many answers to this dilemma:

a) Modify a car alternator: add more magnets, add more "cooper" coiled
parts.  Then you will need less RPM.  You will need to do this with almost
ALL the car alternators that you can find.  If you get an alternator that is
on the 600 RMP then you are VERY NEAR to what any human been (big or small,
child, woman, man) can generate.

b) Build your own alternator: import the magnets from China, very very (and
very) cheap.  Locally (at least in my country) we can add the cooper coils
bobins.  We need a good design and some testing.  Add some circuits (very
cheap too, any medium skilled tech here can build one) for doing the cut
off, the rectification, and other electronic gadgets.

More: the bike/leg combination is not usefull because you move THE WHOLE
LEG.  Too much waste.  Then you transfer all that spend energy to a small
"flywheel" that transfer (by the chain) the movement to the rotor (that is
in the back of the bike).  You need to do this because you need BIG torque
(initial force).  In the case of the "charging batteries" there is not need
to move the weight of any person so no such a need torque is needed.  So, IF
you use a spinning wheel (that is what I have in mind) you move just one
foot and that is good enough to move a BIG wheel that will move the "rotor"
on the alternator (or the pulley on the alternator).  I have done the
calculations and that "foot" movement can generate from 500 to 600 RPM with
a very low and normal "pedaling" (treadling) rhythm.  Since it is in the
"border line" I think we would need to add some extra pulley system to add a
little bit more RPMs.

>*Rule of thumb -- Whatever you may design, remember, as a simple rule

of thumb, that from the alternator you may use, you'd need to provide

each XO laptop about 1.5A of current at 12V for about 2hours to charge

the battery from empty to full.

I am taking note.  Question: how long can the XO work with a full charged
battery ?

(then we can calculate how many "alternator sets" we need for this or that
school)

>It would be my suggestion to plan out the

power solution as much as in detail as possible before implementing

it, it would save you problems that you might face later on!

AMEN!!!! Base line is what we need.

Javier Rodriguez

Lima, Peru

Arjun Sarwal wrote: 

Hi Javier, Caryl and others,

A few thoughts.

* Cost of Alternators -- I agree they are expensive. Have you thought

about taking car alternators? They give 12V and usually have built in

mechanisms for cut-off when the battery is fully charged, and also

would be easily available. In India I've found car alternators to cost

~$100. They give about 35A output.

* I would like to see more variations of human power being explored,

like the one Caryl has mentioned. I think it is a very interesting

idea. However, whatever experience I have had, I have come to realize

that it is very difficult for a human to provide the mechanical power

needed to charge an XO, whatever they may use - legs/hands etc. This

was one of the reasons why we fundamentally wanted animals to drive

our solution and not be human powered.

* Bicycle - Holden Bonwit, cced here was recently working on Bicycle

powered solution at a place near Delhi. I will fish for the link he

sent me, but they concluded that it is difficult to get enough output

from a single dynamo to be able charge XOs

* Battery -- In terms of electrical design it'd be much better to

charge, say a 12V car battery or something rather than directly

charging the XOs. This would basically save us hassles of having to

put a current limiting circuit, and also car batteries or other Lead

Acid batteries can be charged with variable current, for example they

can sometimes get charged much faster when higher current is

available, but the range of current the XOs can take for charging is

limited. But we can get to specifics about electrical design etc later

on.

*Rule of thumb -- Whatever you may design, remember, as a simple rule

of thumb, that from the alternator you may use, you'd need to provide

each XO laptop about 1.5A of current at 12V for about 2hours to charge

the battery from empty to full.

I hope these help in some way. Please let me know if I can provide any

other useful information. It would be my suggestion to plan out the

power solution as much as in detail as possible before implementing

it, it would save you problems that you might face later on!

best regards

Arjun

Message: 2

Date: Mon, 05 May 2008 14:05:32 -0400

From: "info at olpc-peru.info" <mailto:info at olpc-peru.info>
<mailto:info at olpc-peru.info> <info at olpc-peru.info>

Subject: Re: [Peripherals] [support-gang] Alternitive Power for

       Developing Countries

To: Mel Chua  <mailto:mel at melchua.com> <mel at melchua.com>

Cc: Yama Ploskonka  <mailto:yama at netoso.com> <yama at netoso.com>,
peripherals at lists.laptop.org,

       "Community Support Volunteers -- who help respond to \"help AT

       laptop.org\""  <mailto:support-gang at lists.laptop.org>
<support-gang at lists.laptop.org>

Message-ID:  <mailto:481F4C6C.7010604 at olpc-peru.info>
<481F4C6C.7010604 at olpc-peru.info>

Content-Type: text/plain; charset=ISO-8859-1; format=flowed

Hello Mel and all the people on the peripherals list,

I have been discussing the issue of energy with other fellow on the OLPC.

I am honest and I speak directly all the time: I think the solar energy

is not a realistic posibilitie in Peru: there is 100% sunny days in the

Andes JUST 6 months in a whole year.  The worst moments are the 4 to 5

months were some villages (located over the 3,500 meters altitude) get

100% cloudy time, very cloudy, huge rainfall.  According to all the

investigation that I have done (I can send to anyone if you are

interested) the solar devices can provide from 5% to 20% IF there is not

a sunny day.  That is a BIG problem.

My best understanding, based on previous experience when I have work for

a mining company is to build a mechanical device: human driven, leg

driven.  But not a bycecle.  We have built it before but it was without

"cost" restrictions.  It is based on a spinning wheel (I have many here

at my sight).  But when I have put "cost" as a variable to take in

account then I have got the next ideas:

a) Using alternators, in Peru, is expensive.  Each alternator cost

US$300 aprox.

b) We need to import some magnets and assembly the alternator by

ourselves.  The kids on the villages can do it as part of the

"experience".  We must provide the alternators, the copper wire, the

circuit and components for the rectifier, and... the battery (battery is

other hard issue... short live... expensive).  Assembly this "home made"

alternator, connecting to the spinning wheel (that can need a double

wheel or a "pulley" chain) can be an improvement (according to the first

results that we can get).

c) Legs are the ones that will be used.  Not in a bycecle but on a

spinning wheel.  It is totally possible generate enough energy for a

regular laptor with the legs, it will be easier for the XOs.  Providing

energy for the XServers is a totally different issue, I don't agree with

the use of XServers.  I suggest that one of the XOs MUST behave as a

Server (or the whole local XO network should behave as a "shared server"

sharing processing power... but that is a bigger task).

d) Need more energy? Put bigger magnets or "more" copper wire.  Too

heavy to move? Change design: move the copper wire around the magnets.

Too heavy yet? Use concatenated pulleys.

e) Cost?: import the magnets from Korea or other asian manufacturer.

In this moment I don't have the time to develop this pilots (because I

work independently, earning bread and butter for daily living, as

anyone, and my spare time is not good enough to attack the problem in an

efficient way).  So I am passing this info to you (and I can discuss and

help more if there is someone interested in develop this prototypes).

If we don't get an asnwer for the energy problem then we will be

delivering (we ARE delivering) XOs to the towns and villages that "look"

poor in the eyes of the occidental culture but we are forgetting that in

Peru the deep poverty is located in those 80,000 villages (5 million

people) with less than 100 families in each villages, without

electricity, less than FIVE HUNDRED dollars as total ANNUAL income for

the family (with the work of the father, mother and children from 6

years old).  The goverment can not reach them (they reach JUST the 5,000

other villages that contains the rest of the peruvian population, 23

million people).  So IF we deliver XOs just to the towns that HAVE

electricity then we are keeping a "STATUS QUO" that have kept the same

since 1821 (our "independence day" from the old spaniards conquerors).

We need to be part of the solution and not be part of the problem.

We will develop this "energy" gadget (this or other one!) and then ALL

the responsible people will be more than happy to bring the XOs to those

villages.  Then we, all, be very happy.  Until then the "One Laptop Per

Children" will not be a dream.

Best regards,

Javier Rodriguez

Lima, Peru

(just for the record: my other two nightmares are: internet connection

without any VSAT (or paying to the telephone company)... building

something like UUCP or a UUCP revival... and content, content, content).

Mel Chua wrote:

Moving discussion to "peripherals" list (please reply to

peripherals at lists.laptop.org - subscription info at

http://lists.laptop.org/listinfo/peripherals)...

Chris Carrick, one of the staff members for the grassroots office in

Chicago this summer (our resident mechanical engineer & green guy), will

be working on getting many "ideas with prototypes built and tested" as

well as "simple instructions for replicating them made available to

empower the folks to generate their own power." (More of a "here's how

to design your *own* power solutions!" in the end, even more than a

"copy ours!" resource.) So your wish will be granted, Caryl. :)

-Mel

Caryl Bigenho wrote:

Yes, I thought of that too.  But who would ride the bike?  Where would

they go?  Would it be an exercise bike?  Do these folks really need more

exercise?  If they, or someone in the family, will be riding around

anyway, it would work.  But if they are walking most places (as the

folks in the Andes tend to do), the bicycle is not a luxury they have at

hand.  Still in some places it would probably be a great idea.

I would love to see lots of ideas with prototypes built and tested and

simple instructions for replicating them made available to empower the

folks to generate their own power.  Call it "Power Empowerment!"

 > From: akonstam at sbcglobal.net

 > To: support-gang at lists.laptop.org

 > Date: Sun, 4 May 2008 14:40:55 -0500

 > Subject: Re: [support-gang] Alternitive Power for Developing Countries

 >

 > On Sun, 2008-05-04 at 08:26 -0700, Caryl Bigenho wrote:

 > > Hi...

 > >

 > > Yes, I've seen that weza treadle. The price is way to high for

 > > developing countries...it costs more than the XO! I'm looking for a

 > > charger that can be made inexpensively from something that may be

 > > readily available. It might even be possible to retrofit one of the

 > > sewing machines so it could sew and charge at the same time. That way

 > > Mom could recharge Junior's XO while she was making clothes or

 > > whatever!

 > >

 > > I wil take a look a the other list and move this idea there later this

 > > morning.

 > >

 > > Caryl

 > I am sure someone has thought of this but a bicycle would make an ideal

 > charging device.

 > --

 > =======================================================================

 > Romance, like alcohol, should be enjoyed, but should not be allowed to

 > become necessary. -- Edgar Friedenberg

 > =======================================================================

 > Aaron Konstam telephone: (210) 656-0355 e-mail: akonstam at sbcglobal.net

 >

 > _______________________________________________

 > support-gang mailing list

 > support-gang at lists.laptop.org

 > http://lists.laptop.org/listinfo/support-gang

------------------------------------------------------------------------

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Message: 3

Date: Mon, 5 May 2008 14:35:57 -0700

From: Caryl Bigenho  <mailto:cbigenho at hotmail.com> <cbigenho at hotmail.com>

Subject: [Peripherals] Alternitive Power for Developing Countries

To:  <mailto:info at olpc-peru.info> <info at olpc-peru.info>,
<mailto:peripherals at lists.laptop.org> <peripherals at lists.laptop.org>

Message-ID:  <mailto:BLU108-W40798E83494CA5CAB3D780CCD70 at phx.gbl>
<BLU108-W40798E83494CA5CAB3D780CCD70 at phx.gbl>

Content-Type: text/plain; charset="iso-8859-1"

Hello Javier Rodriguez and, all the other folks on the peripherals list,

After seeing the creative things Arjun Sarwal is doing with cow-power in
India, I started thinking of other possibilities. I remembered my
grandmother's old treadle sewing machine and how excited she was to have it
electrified.  Later, I saw many being used 35 years ago in regions in the
Yucatan where there was no electricity.

Here is a link to a picture of what they look like.  It is the one on the
left.

http://www.sil.si.edu/DigitalCollections/Trade%2DLiterature/Sewing%2DMachine
s/

Many of these machines still exist.  i see them at estate auctions every
summer in Montana.  There must be thousands throughout the world.  I have
twice tried bidding on just the treadle mechanism of one on ebay. I lost out
on the bidding for both, but have hopes of finding one in Montana this
summer.

When I get one, I intend to try to set it up as a combination desk/power
source to run an XO.  If it works and doesn't cost too much to set up, it
might be something that could be replicated all over the world where these
old machines still exist...some probably still being used without
electricity.

Javier, have you seen any of these machines in rural Peru?  Are they still
being used to sew?  Would there be a need to try to design it to continue to
be used as a sewing machine but to generate power at the same time?

It might also be possible to manufacture a similar mechanism, at a modest
cost.  But, the idea of recycling the old ones has a lot of appeal. I was
also wondering if an old automobile generator could be adapted to work with
it.  Perhaps it would require too much torque to work.

It may be just a crazy idea, but if cow-power works, maybe this will too. If
and when I do this project, I will probably need some advice from you folks.
Any suggestions for starters?

Caryl

BTW, Could AJ's Cow-power generator be adapted to run on Llama power?  How
about donkey power?  Goat power?

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Message: 4

Date: Mon, 5 May 2008 23:30:06 +0000

From: "Alfonso de la Guarda"  <mailto:alfonsodg at gmail.com>
<alfonsodg at gmail.com>

Subject: Re: [Peripherals] Alternitive Power for Developing Countries

To: "Caryl Bigenho"  <mailto:cbigenho at hotmail.com> <cbigenho at hotmail.com>

Cc: peripherals at lists.laptop.org

Message-ID:

        <mailto:ed60564a0805051630t5deb641ap825b2b17c65495c8 at mail.gmail.com>
<ed60564a0805051630t5deb641ap825b2b17c65495c8 at mail.gmail.com>

Content-Type: text/plain; charset="iso-8859-1"

Hello,

In the COS (www.cos-la.org), we are working some months ago in some options

for that, specially with a portable solar panel trying to reduce their cost

(about 60 dollars each).  The device -commercially available as cell

charger- is really small and can charge the XO without any problems.  In a

field test in Junin and Arahuay (Per?) the panels works great, in fact, in

the recent event of FLISOL in Huancayo (Junin-Peru) for the OLPC project, we

test the solution (commercial) between 3400 mts and 4500 mts (Ticlio).

Antonio Ramirez, Carlos Reinoso and who writes now are working in our breaks

on this task (reduce the cost for about 25 dollars each).

2008/5/5 Caryl Bigenho  <mailto:cbigenho at hotmail.com>
<cbigenho at hotmail.com>:

 Hello Javier Rodriguez and, all the other folks on the peripherals list,

After seeing the creative things Arjun Sarwal is doing with cow-power in

India, I started thinking of other possibilities. I remembered my

grandmother's old treadle sewing machine and how excited she was to have it

electrified.  Later, I saw many being used 35 years ago in regions in the

Yucatan where there was no electricity.

Here is a link to a picture of what they look like.  It is the one on the

left.

http://www.sil.si.edu/DigitalCollections/Trade%2DLiterature/Sewing%2DMachine
s/

Many of these machines still exist.  i see them at estate auctions every

summer in Montana.  There must be thousands throughout the world.  I have

twice tried bidding on just the treadle mechanism of one on ebay. I lost out

on the bidding for both, but have hopes of finding one in Montana this

summer.

When I get one, I intend to try to set it up as a combination desk/power

source to run an XO.  If it works and doesn't cost too much to set up, it

might be something that could be replicated all over the world where these

old machines still exist...some probably still being used without

electricity.

Javier, have you seen any of these machines in rural Peru?  Are they still

being used to sew?  Would there be a need to try to design it to continue to

be used as a sewing machine but to generate power at the same time?

It might also be possible to manufacture a similar mechanism, at a modest

cost.  But, the idea of recycling the old ones has a lot of appeal. I was

also wondering if an old automobile generator could be adapted to work with

it.  Perhaps it would require too much torque to work.

It may be just a crazy idea, but if cow-power works, maybe this will too.

If and when I do this project, I will probably need some advice from you

folks.  Any suggestions for starters?

Caryl

BTW, Could AJ's Cow-power generator be adapted to run on Llama power?  How

about donkey power?  Goat power?

_______________________________________________

Peripherals mailing list

Peripherals at lists.laptop.org

http://lists.laptop.org/listinfo/peripherals

--

--------------------------------

Alfonso de la Guarda

COS

www.cos-la.org

www.delaguarda.info

Telef. 97550914

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