Shine Stream

ScienceDaily (Feb. 5, 2008) — Researchers at MIT and Texas Instruments have unveiled a new chip design for portable electronics that can be up to 10 times more energy-efficient than present technology. The design could lead to cell phones, implantable medical devices and sensors that last far longer when running from a battery.

The innovative design will be presented Feb. 5 at the International Solid-State Circuits Conference in San Francisco by Joyce Kwong, a graduate student in MIT’s Department of Electrical Engineering and Computer Science (EECS).*

The key to the improvement in energy efficiency was to find ways of making the circuits on the chip work at a voltage level much lower than usual, Anantha Chandrakasan of MIT explains. While most current chips operate at around one volt, the new design works at just 0.3 volts.

Reducing the operating voltage, however, is not as simple as it might sound, because existing microchips have been optimized for many years to operate at the higher standard-voltage level. “Memory and logic circuits have to be redesigned to operate at very low power supply voltages,” Chandrakasan says.

One key to the new design, he says, was to build a high-efficiency DC-to-DC converter-which reduces the voltage to the lower level-right on the same chip, reducing the number of separate components. The redesigned memory and logic, along with the DC-to-DC converter, are all integrated to realize a complete system-on-a-chip solution.

One of the biggest problems the team had to overcome was the variability that occurs in typical chip manufacturing. At lower voltage levels, variations and imperfections in the silicon chip become more problematic. “Designing the chip to minimize its vulnerability to such variations is a big part of our strategy,” Chandrakasan says.

So far the new chip is a proof of concept. Commercial applications could become available “in five years, maybe even sooner, in a number of exciting areas,” Chandrakasan says. For example, portable and implantable medical devices, portable communications devices and networking devices could be based on such chips, and thus have greatly increased operating times. There may also be a variety of military applications in the production of tiny, self-contained sensor networks that could be dispersed in a battlefield.

In some applications, such as implantable medical devices, the goal is to make the power requirements so low that they could be powered by “ambient energy,” Chandrakasan says-using the body’s own heat or movement to provide all the needed power. In addition, the technology could be suitable for body area networks or wirelessly enabled body sensor networks.

“Together, TI and MIT have pioneered many advances that lower power in electronic devices, and we are proud to be part of this revolutionary, world-class university research,” said Dr. Dennis Buss, chief scientist at Texas Instruments. “These design techniques show great potential for TI future low-power integrated circuit products and applications including wireless terminals, battery-operated instrumentation, sensor networks and medical electronics.”

*Kwong carried out the project with MIT colleagues Anantha Chandrakasan, the Joseph F. and Nancy P. Keithley Professor of Electrical Engineering, and EECS graduate students Yogesh Ramadass and Naveen Verma. Their Texas Instruments (TI) collaborators are Markus Koesler, Korbinian Huber and Hans Moormann. The team demonstrated the ultra-low-power design techniques on TI’s MSP430, a widely used microcontroller. The work was conducted at the MIT Microsystems Technology Laboratories, which Chandrakasan directs.

The research was funded in part by a grant from the U.S. Defense Advanced Research Projects Agency.

Adapted from materials provided by Massachusetts Institute of Technology, via EurekAlert!, a service of AAAS.

Texas Instruments Inc. and the Southern California Edison Company said today that they had developed a way to use inexpensive low-purity silicon in solar cells, which could halve the cost of converting sunlight into electricity.

Texas Instruments said it was building a lab in one of its Dallas plants to develop a manufacturing process for the new photovoltaic cell, which took six years to develop.

The company hopes to perfect a manufacturing process by the end of next year and will then determine whether commercial production is viable, Ted Jernigan, a spokesman, said. Field trials will be made later this year, he said.

The companies said their process used inexpensive silicon costing $1 to $2 a kilogram, compared with pure silicon costing up to $75 a kilogram. Their process used heat to remove impurities from silicon.

The goal is for the cells to produce electricity for about 14 cents a kilowatt-hour, about what Southern California Edison charges residential customers. The output of the cells peaks in the late afternoon, when demand is typically greatest.

Both companies have a history of solar energy projects. Southern California Edison has developed a 100-megawatt solar thermal plant in Barstow, Calif. Texas Instruments took part in several Energy Department programs on photovoltaic research in the 1970’s.

 By AP, The New York Times

GUDDA, India (CNN) — In Gudda, a village with very little, residents are literally beaming. Just two years ago, villagers had never seen light after dark, unless it came from the moon. Then, solar light arrived and changed everything.

“When the lanterns first arrived, the villagers asked, ‘What is this?’ ” says Hanuman Ram, the local solar engineer. “I explained to them how it worked. Then slowly, as people saw it, they said, ‘Wow, what a thing this is!’ ”

There are no real roads that lead to the tiny village in the state of Rajasthan in northwestern India, home to about 100 families. There are only thin strips of tar dotted with massive potholes that force vehicles into thick brush. Other times, cars have to maneuver over just dirt.

There is no electricity — power lines don’t extend out here. Water is scarce, too. At the village well, women balance jugs of water on their heads, deftly evading the livestock that saunters along.

It’s a simple lifestyle of farming, tending to goats, caring for children and carrying out household chores — a daily routine that hasn’t changed much over the centuries.

That’s why light transformed Gudda. Villagers could play music at night. Children could study well past sundown.

As Yamouna Groomis kneads dough for her family’s evening meal, she blows through a pipe every once in a while to keep a flame burning in an outdoor clay pit. Her days used to end when the sun went down. She smiles as she proudly flicks on a solar lamp.

When I saw this light coming on for the first time, I was very happy,” she says.

The light is powered by a solar panel on her roof that charges a battery. Panels can be seen on almost every rooftop in Gudda.

By Arwa Damon
CNN

When it comes to backyard or pathway lights, forget practical and boring ? think fun and fancy. You can create a soothing, inviting mood with unique and attractive outdoor lighting.

Better yet, you can use solar powered outdoor lights, to save energy and save yourself digging ditches, laying the wire and attaching it to a junction box. When choosing an outdoor solar powered light you will need to consider a variety of factors in order to match the function you want with the available lighting choices.

Solar lights use small photovoltaic cells that absorb sunlight during the day and turn it into energy. Rechargeable batteries store the energy, making it available at night when it is needed. LED (light emitting diode) bulbs, which require little power and last 10 times longer than incandescent bulbs, provide the illumination. There is no wiring necessary to connect the lights to each other or to the electric grid.

For starters, there are three kinds of garden solar lights:

Path lights: solar powered path lights come in a variety of fairly standard styles from modern to classic. They can be hung from a pole or embedded in the ground to light a dark walk or guide the way. And because there is no wiring involved, they can easily be moved to a new location whenever the remodeling bug hits you.

Decorative accent lights: For more fun and fancy, check out the solar powered garden lights that glow with attractive designs and colors. Position them right and it will be like having a giant-size firefly in your yard. These unique lights, made of blown glass or hand-made materials, will add a touch of whimsy to your yard, when placed in and around your shrubs and flower beds. You can find these lights online or in home improvement stores and garden centers. Most have the glowing light perched on top of a slim stake that can easily be pushed into the soil. The small solar collector is attached to the stake and must receive direct sunlight each day in order to charge the batteries.

Spot lights: For focused lighting, there are spotlights that can be tucked into the garden foliage illuminating a unique landscape feature. The one we tested from Gaiam has a cord attached to the small solar panel, which is placed in direct sunlight, up to 8 feet away from the lights. On some solar spotlights, the solar panel is attached to the spotlight head, which must have direct sunlight to recharge the batteries.

 -Heidi Hunt, Mother Earth News