Internet devices powered by Wi- Fi and other telecommunications signals will make small computers and sensors more pervasive. Availability: 2-3 years by Mark Harris Even the smallest Internet-connected devices typically need a battery or power cord. Not for much longer. Technology that lets gadgets work and communicate using only energy harvested from nearby TV, radio, cell-phone, or Wi- Fi signals is headed toward commercialization. The University of Washington researchers who developed the technique have demonstrated Internet-connected temperature and motion sensors, and even a camera, powered that way. Transferring power wirelessly is not a new trick. But getting a device without a conventional power source to communicate is harder, because generating radio signals is very power-intensive and the airwaves harvested from radio, TV, and other telecommunication technologies hold little energy. Shyamnath Gollakota and his colleague Joshua Smith have proved that weak radio signals can indeed provide all an Internet gadget needs, using a principle called backscattering. Instead of generating original signals, one of their devices selectively reflects incoming radio waves to construct a new signal—a bit like an injured hiker sending an SOS message using the sun and a mirror. A gadget using the technique absorbs some energy from the signal it is modifying to power its own circuits. Breakthrough Wireless gadgets that repurpose nearby radio signals, such as Wi- Fi, to power themselves and communicate. Why It Matters Freeing Internet-connected devices from the constraints of batteries and power cords will open up many new uses. Key Players in Harvesting Radio Waves - University of Washington - Texas Instruments - University of Massachusetts, Amherst “ We can get communication for free,” says Gollakota. RFID chips for the contactless smart cards used in mass transit also rely on.
The next big thing in solar energy could be microscopic. Scientists at MIT and Harvard University have devised a way to store solar energy in molecules that can then be tapped to heat homes, water or used for cooking. The best part: The molecules can store the heat forever and be endlessly re-used while emitting absolutely no greenhouse gases. Scientists remain a way’s off in building this perpetual heat machine but they have succeeded in the laboratory at demonstrating the viability of the phenomenon called photoswitching. An Atlantic Special Report Read More “ Some molecules, known as photoswitches, can assume either of two different shapes, as if they had a hinge in the middle,” MIT researchers said in statement about the paper published in the journal Nature Chemistry. “ Exposing them to sunlight causes them to absorb energy and jump from one configuration to the other, which is then stable for long periods of time.” To liberate that energy all you have to do is expose the molecules to a small amount of light, heat or electricity and when they switch back to the other shape the emit heat. “ In effect, they behave as rechargeable thermal batteries: taking in energy from the sun, storing it indefinitely, and then releasing it on demand,” the scientists said. The researchers used a photoswitching substance called an azobenzene, attaching the molecules to substrates of carbon nanotubes. The challenge: Packing the molecules closely enough together to achieve a sufficient energy density to generate usable heat. It appeared that the researchers had failed when they were only able to pack fewer than half the number of molecules needed as indicated by an earlier computer simulation of the experiment. But instead of hitting a projected 30 percent increase in energy density, they saw a 200 percent increase. It turned out that the key was not so much packing azobenzene.
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