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Charging Laptops, not Electrocuting Kids: The XO Charging Rack

April 18th, 2008 By:Ties · 7 Comments

Here below we see Ram; not only software developer extraordinaire, but also electrical engineer extraordinaire, who in his spare time is known to make and install small micro-hydro installations for rural villages in Nepal. For our pilot schools we needed XO loading stations that were low-cost, practical and cheap. So we set Ram to work.

We didn’t want to run power cables to each child’s desk. 1) There would be substantial power loss using regular AC power strips 2) kids would trip on them, esp. the second graders. 3) Most power strips in Nepal are of quite poor design and frequently cause sparks when you insert a power plug. 4) We feel that tethering kids to power strips would limit much of the ad-hoc collaboration that the XO inspires.

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Ram Krishna Singh standing proud with his creation, the XO charging rack. It accommodates 25 XO’s. We will put a step in front of it so the second graders can reach the top shelf. The power rack will go in the back of the class. Kids will place the XO’s inside the rack in the morning and take them out as needed.

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In the top part of this picture you can see the cutoff switch. We want to minimize the number of times the child has to plug in and unplug the XO power connector, thus minimizing the possibility of electrocution.

We need a more elegant way to tie down the cables so they won’t get tangled.

The XO goes in front first so the child doesn’t have to reach in to far to grasp the DC portion of the plug.

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A large number of students at the pilot school don’t have electricity at home, but some do. Ideally we would like to have two chargers for each XO, one that stays at the school and one at home. This would be one less thing for the kids to carry around, we are especially concerned about the second graders. We don’t want them frequently plugging in and unplugging XO’s from various power outlets. Most power outlets in Nepal are of quite poor design and often emit sparks. We will have to build our power adapters and/or harrass OLPC to send us a lot more power adapters.

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7 responses so far ↓

  • 1 Sarah Elkins // Apr 19, 2008 at 5:34 am

    That multicharger rack is awesome!

  • 2 Sameer Verma // Apr 19, 2008 at 7:27 am

    Perfect example of ingenuity at work. The workmanship on the rack looks clean too.

    The extra chargers you are looking for can be garden variety 12 V chargers. The plug is a bit specific though (Digikey). See http://wiki.laptop.org/go/Battery_and_power#Mechanical

    I worked out a slightly different solution to mix and match power sources, but I wouldn’t recommend it :-)

    http://sameerverma.org/blog/?postid=171

  • 3 skierpage // Apr 20, 2008 at 3:18 pm

    Would it not be more efficient and safer to have a single central transformer to the XO’s DC 12 V, and then just plug in multiple DC cables?

    http://wiki.laptop.org/go/Hardware_specification#External_connectors

  • 4 Peter Rock // Apr 21, 2008 at 6:13 am

    Beauty!

  • 5 Bishwa // Apr 23, 2008 at 1:08 pm

    Looks great and I am sure it works great too. Kudos folks!!

  • 6 Hauke edeler // Apr 27, 2008 at 10:48 pm

    awesome.

  • 7 Kevin Cole // Apr 8, 2009 at 8:08 pm

    Hmmmm… Methinks, with a touch of security, and perhaps a logging/inventory mechanism, a model for a Lending Library…

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