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Education Handhelds Power News

Tablet Prototype Needs No External Power Supply 110

timothy writes "I'd like to see computing devices with no need for an external power supply — an e-book reader, a general knock-about PDA, a phone — all kinds of things. But there's a certain heart-strings appeal to such a computer intended as an educational tool for precisely those kind of places where basic infrastructure (like the provision of electricity) is a stumbling block. Perhaps built-in solar makes more sense, in more places, than the hand-cranked power the OLPC project ended up dropping from their laptops-for-kids program."
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Tablet Prototype Needs No External Power Supply

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  • by steveha ( 103154 ) on Monday November 15, 2010 @09:50PM (#34238470) Homepage

    Perhaps built-in solar makes more sense, in more places, than the hand-cranked power

    Perhaps it does, perhaps it does! If, that is, you can build the device such that it can run off of built-in solar. That's the real trick, isn't it.

    A simple four-function calculator trivially can run of a little photocell, and this has been true for decades. So why didn't OLPC simply put a little photocell on the XO-1? Because a little cheap photocell doesn't produce anywhere near the needed power needed by an XO-1.

    And, the hand-cranked power is a particularly irritating straw man. A long, long, time ago, when OLPC was just an idea, they thought about a hand crank, and even made a mockup of what it might look like. But it was never made. Reasons: 0) some kids live in places with a decent electrical grid, so there is no need to add the cost of a generator to every single laptop; 1) an external generator can be trivially replaced if it breaks, without the laptop itself needing to be repaired; 2) a crank built-in to the laptop adds mechanical cranking strain on the laptop, necessitating the laptop being made sturdy in otherwise-needless ways; and 3) little kids are not known for their arm strength, so a generator that could be operated by leg muscles was deemed better. OLPC announced that a pull-cord generator would be the human powered generator, but as far as I can tell from a few quick Google searches just now, the pull-cord generator is still vapor.

    I recently sent my XO-1 to India for use by the Bharti Integrated Rural Development Society []
    (B.I.R.D.S.) and I looked into a solar array for it. I found one for about $200 that should operate an XO-1 continuously and charge the battery in about an hour. I also found lots of other solar arrays that cost way more than that. So, the most affordable solar array I found cost more than the XO-1. As I understand it, the B.I.R.D.S. school has electrical power only when they run their generator, which is a few hours a day, so my hope is that the XO-1 will be useful just with the generator power. (Conveniently, the power supply on an XO-1 accepts any AC from 100 to 240 Volts, at 50 or 60 Hz, so they should be able to just plug it in with a plug adapter.)

    Note that TFA says "...the I-slate is the first of a series of electronic notepads being built around a new class of low-energy-consumption microchips under development...". So, one of the reasons the OLPC XO-1 isn't powered with a little solar array is that it was developed half a decade ago, and the new ultra-low-power chips are, well, new.

    Isn't it enough to say "This is a cool new technology and I'm excited about it" rather than talking about how much better it is compared to a half-decade-old technology?

    P.S. I put an 8 GB flash card in the SD card slot on the XO-1. On the card I put a copy of Wikipedia for Schools [], which takes up about 4 GB; then I put some health and medical books [] and a bunch of classic fiction books (for students to read when studying English). I updated the OS on the OLPC to the latest build, and installed a typing tutor program (Typing Turtle) from Sugar Labs []. I found a public-domain copy of The Elements of Style [] and a few other free textbooks. Finally, I put a few books on Python Programming. I haven't had any email back from B.I.R.D.S. telling me anything, so I have no idea how it's working out.

    I have to say, an XO-1 loading books straight off an SD card is a pretty nice book reading platform! And with the backlight off, to read books in monochrome, battery life should be pretty good. I'm hoping they will find the XO-1 to be useful.


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