After a year of testing in a remote village in India, researchers are ready to scale up production of an ultra-low-power $35 tablet called the I-slate.
The I-slate is designed to teach math and other subjects to students whose schools lack electricity or to students who don’t have access to teachers at all. The device will enter full-scale production next year, and will be the first device to apply a low-power technology called probabilistic CMOS (complementary metal-oxide semiconductor) to achieve a longer battery life.
The probabilistic CMOS approach is simple: run an ordinary microchip less stringently, sacrifice a small amount of precision, and get huge gains in energy efficiency in return. Probabilistic CMOS (CMOS refers to the technology behind most of today’s chip technologies) works particularly well in graphics and sound processing, since human vision and hearing aren’t perfect, and small errors are therefore undetectable.
Krishna Palem, a professor at Rice University and director of the Institute for Sustainable Nanoelectronics at Nanyang Technological University, first demonstrated probabilistic CMOS in 2006. Palem is now working on getting the technology into applications including a low-power hearing aid. In the educational tablet device, Palem says, probabilistic chips will enable huge power savings: the educational tablet will require just three watts of power, meaning it can be powered entirely by small solar cells like those on a pocket calculator.
The I-slate looks similar to an iPad, with a seven-inch liquid-crystal touch screen display. But it’s not a full tablet computer—in fact, unlike other hardware supplied to disadvantaged children through efforts such as One Laptop Per Child, it’s not a computer at all, and does not have an operating system. “It’s an elaborate, single-function device,” says Palem. Kids can read from a preloaded textbook or take notes and work out math problems using a stylus on a “scratch pad” to one side of the screen. The device can store a few pages of notes.
Palem’s group at Nanyang Technological University is developing the I-slate in collaboration with the Indian nonprofit organization Villages for Development and Learning Foundation and the Los Angeles design firm Seso. Last year, the group tested prototype I-slates loaded up with a math textbook and exercises at a school in Mohd Hussainpalli, a village about 70 miles southwest of Hyderabad. In this region, electricity is unreliable, and some villages don’t have teachers.
When designing an embedded system choosing which tools to use often comes down to building a custom solution or buying off-the-shelf tools.