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8 in one anti-electrocution and tangle-free XO power supply to be used in the classroom to improve safety, convenience and battery life.


Location and Intended Users

For classroom settings, libraries, study halls, media centres and community centres.


  • Children using the power adapters that come with the XO are potentially in danger because they have to get so close to mains electricity. At times, to remove the adapters from the wall outlet children (and adults) have to introduce their fingers between the outlet and the converter for better leverage (dangerously close to the metallic pins).
  • It can be difficult to find enough mains wall sockets, or mains strips which can accept enough power supplies.
  • The gang charger proposal requires the purchase of an additional battery for every XO, and the purchase of the gang charger itself. By using battery power constantly the batteries life expectancy will be reduced considerably.
  • Children have to carry the converters back and forth, every day, or don't have it when needed.
  • Children lose their chargers.
  • Children damage their chargers.
  • Fitting enough chargers into power strips is proving to be a problem. Requests have been made to change the design of the charger. The XOctoPlug could solve these problems.


  • Children are kept away from high voltages.
  • Children won't be plugging and unplugging adapters.
  • Children won't fight over outlet connection or charging time.
  • Children can work while they charge (not so with the gang-chargers).
  • Even if it gets hot, children won't need to touch the XOctoPlug.
  • No need to change batteries during the day.
  • More organized cabling (They will not be connected to the same high voltage outlet, risking that the XOs fall down or children trip).
  • Adapters will not get lost because they can leave the individual ones at home (where adult connects it).


  • Cables running to the XOctoPlug still remains a potential hazard for children, although is considerably better than the current environment.
  • The XOctoplug will take up room on the desk.
  • If the XOctoplug is used children must sit in clusters, which is not always traditional for classrooms.
  • Students might be drawing anywhere from milliwatts (one machine on trickle) to 120W (8 machines at full draw). It might be a challenge making a power converter that is efficient over that large a range.



See the contact charger on Apple's Emate 300 from 1997, a device similar in construction to the XO.

Adapters and Recycled Used PC Power Supplies

Use an existing PC power supply and just make adapters from PC power to XO plug. The 12 volt rail on the typical PC is probably powerful enough to run quite a few, and the hardware exists all over the place. We just need adapters. AaronPeterson 16:57, 23 December 2007 (EST)

This represents a low cost solution, but it these power supplies are large, often require cooling fans and not designed for children to be around. JoshSeal 19:03, 23 December 2007 (EST)
Most PC power supplies have their own cooling fans. They are in an enclosure of their own and are designed and built to safety standards in their own right. They may have several 12v/5v connectors, so all that is needed are adaptors. My experiences in africa lead me to understand that most people would find this solution more than adequate. OK so a recycled power supply would not be green, you could always paint them green. Keith 02:39 25 January 2008 (GMT)
I think there will be many different solutions for many different places. The main purpose of the XOctoPlug is to get power to every XO in a classroom in the safest possible way. Safety, in regards to power and hazards caused by cables, really is the priority with this product. The XOctoPlug is a great solution for schools who can afford the small additional cost. JoshSeal 11:23, 27 January 2008 (EST)

Christmas Tree Style Adapters

Christmas tree lights already have the solution to the linear vs hub. They have an in, and an out for chaining.


plug socket plug

if an all in one design were chosen,It would be nice if the cord plugs could be made the same. The socket should probably be further towards one side as to allow for stringing longer distances. then length of the small side should be about 4 feet to account for desk height, so maybe 6ft socket 4 ft. This may have a lower total bill of materials but is not as configurable as:


plug plug tri socket plug plug

which probably has existing cables available, we just need to make the tri socket. This also has the benefit of not being as much of a trip hazard, because the junctions will pop out.


pc hdd to olpcadapter

pc power supply already has many 12 volt splitters.

We should also make the wall charger just have a socket, and use the same cables for all devices. yes total bill of materials will be higher, but the flexibility and reduction of trip hazard would be worth it.

Car Charger

Car alternators generate considerable power. In many developing nations -- taxi-vans, pickups and mopeds are common-place. An option to easily connect a portable heavy duty battery in parallel to the car's battery could take advantage of the 50A+ generation capability of the alternator while on local journeys. Alternatively a bulk battery charger box could charge 20 or more batteries.

Ceiling Hung Cables

To prevent children from tripping over cables, they could be hung from the ceiling instead.

Is this really a safer system and would a teacher be happy with cables hanging from the ceiling? JoshSeal 19:00, 3 February 2008 (EST)

Product Requirements

  • Anti-trip mechanism. Cables running from wall to XOctoPlug, then cables running from XOctoPlug to XO must either be designed in a way that tripping is impossible, or that if tripping occurs both child and XO remain safe and undamaged. Possible solutions:
    • Magnetic power connectors or quick release mechanism - this should be located between XO and XOctoPlug
    • Ceiling hung power (possibly unattractive)
    • Secure fixings for cables
    • Sand/dirt/grit fillable cable covers
  • Should be designed to work in both group environments and lined desk setups.
  • Include surge protection
    • 4000 Joules is a high level of surge protection
    • 1000 Joules is an acceptable amount.
  • Possibly include a meter showing how much power is available and hence how many XOs can be plugged in.
  • Why not go with linear power distribution? A single cable with tap in points, or multiple cables daisy chained together.

Alternative Designs


CentiPower is a concept which has been proposed to better suit classrooms which have their students sit in lines, rather than in groups. However CentiPower may also be a good solution for group work as well. User research is commencing to determine the best form factor.



XOctoPlugs and XOs.JPG
XOctoPlugs - P2 - 01.JPG
XOctoPlugs - P2 - 02.JPG

In Field Testing

Khairat School - India


  • Initial Idea: Carla Gomez Monroy, 5th September 2007
  • Prototyping: Joshua Seal
  • Additional Design Ideas: John Watlington and Michael Bove