My ideal for developing countries

Drop in for a chat and a cup of tea

13 posts
by Stonehouse » Thu Apr 05, 2012 10:57 am
My company supplies energy efficient computers for schools in Kenya.  Having seen the Raspberry Pi I would love to use it in a thin client environment with the following

1. Power through ethernet

http://en.wikipedia.org/wiki/P.....r_Ethernet

2. The thin client itself (preferably with Edubuntu)

3. USB monitor

http://gadgetprofile.com/specs.....c-e1649fwu

Does this combination sound achievable?  It would be a very energy efficient system.

Thanks
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by nick.mccloud » Thu Apr 05, 2012 11:38 am
Stonehouse said:


1. Power through ethernet


Not possible at present as the board doesn't support it.


3. USB monitor


Throughput/robustness/reliability may be a problem. With the composite output they could use a TV.
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by Stonehouse » Thu Apr 05, 2012 11:59 am
nmcc said:

Throughput/robustness/reliability may be a problem. With the composite output they could use a TV.

Hi,

Thanks for the input.  I'm afraid a TV is something that they would not have because they are too expensive and require too much energy.  We have energy efficient 12 v led monitors but I just liked the idea of reducing the energy consumption even more and reducing the wiring at the same time.

Ah well, still on for thin client use then?
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by morphy_richards » Thu Apr 05, 2012 12:02 pm
1. Power through ethernet

Not possible at present as the board doesn"t support it.

Is it feasible to create a device that attaches to the network, kind of like a terminator (obviously not a terminator) that could draw the power and supply it to the pi? In my head I see it costing about £2.50 in components.
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by Stonehouse » Thu Apr 05, 2012 12:07 pm
Kind of like an 'in between'?  That would be good
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by morphy_richards » Thu Apr 05, 2012 12:15 pm
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by Stonehouse » Thu Apr 05, 2012 12:44 pm
That looks great!

http://www.ebay.co.uk/sch/i.ht.....Categories

Hooray!  That is that bit sorted.

What about the monitor?  This was mentioned.


Throughput/robustness/reliability may be a problem.


What kind of problem I wonder?
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by nick.mccloud » Thu Apr 05, 2012 1:07 pm
Stonehouse said:



Throughput/robustness/reliability may be a problem.


What kind of problem I wonder?


It's running through a shared USB port, it will need drivers compiling for ARM linux, it may fall apart at the drop of a hat and may not last that long - it looks distinctly like cheap plastic to me - will that survive being ferried about and pawed by many users?

Apart from that, I'm sure it will be fine ;-)
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by mahjongg » Thu Apr 05, 2012 1:10 pm
The real "power over ethernet" system is complex because it uses high voltages @ low current to transfer a lot of power (>10Watt) with minimal loss over long cables, and also use a complex "nature of the receiver" polling system to see if the receiver is of the right "type", and what its power requirements are, thus real power over ethernet is a system, that by nature requires a lot of expensive components.

But if not adhering to any standard is not a problem, and you only want to transfer small amounts of power over relatively short distances (less than a hundred meter) you could just use a few unused wires or the RJ-45 connector to directly transfer power to the powered device from a central power supply.

The R-PI only needs 5V at a few hundred mA, so the voltage loss from a short cable is negligible.

My solution would be to use the wire pair for pins 4 & 5, disconnect them from the ethernet connector at both ends of the connection (RPI and ethernet hub) and use that pair to transfer 5V from a central power supply to power all the R-PI's connected.

If one pair isn't enough you can repeat the same with pair of pins 7 & 8.

Take care not to reverse polarity, or you will destroy the R-PI.
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by Stonehouse » Thu Apr 05, 2012 1:27 pm

It's running through a shared USB port, it will need drivers compiling for ARM linux, it may fall apart at the drop of a hat and may not last that long – it looks distinctly like cheap plastic to me – will that survive being ferried about and pawed by many users?


AOC monitors are quite good, I have used them in rural schools in Kenya and they stand up pretty well.  They will be fixed in place so not slapped about by pupils, who incidentally are very respectful of the technology, very aware of the cost of it, and generally very well behaved (certainly compared to UK pupils - I am a teacher, before you ask).  I take your point re the drivers

@mahjongg - thanks for the info and suggestions.  The upshot is that I will have to get all the kit together and play around with it.
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by malenaah » Fri Jun 22, 2012 11:30 am
Hi,

I would love to hear more about your projects in Kenya. We just set up an ICT center in Nakuru, Kenya. The company I work for sponsor a few projects like this, and we are now looking in to another project in Latin America. My wish is that we can set up a low power consumption IT center just as you describe and I've had the exact same questions on how we can use the Raspberry Pi for theses projects, with exactly the same monitor as you mentioned above. Do you have more information on your projects that I could read about? Would really appreciate it, and would love to follow your progress in finding a good usage of the Raspberry Pi as a thin client and a low power consumtion monitor.

Thanks in advance!

Regards,
Malena
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by aGreasyRangoon » Thu Jan 24, 2013 11:59 pm
Did the drivers for the AOC e1649Fwu ever come to fruition? I have one and would love to hook the RPi to it!
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by DavidS » Sat Jan 26, 2013 1:24 am
Also if you wish to use that monitor you will need to add apowered hub to your list of components, as it draws to much power for the RPi to supply directly.
ARM Assembly Language: For those that want: Simple, Powerful, Easy to learn, and Easy to debug.
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