Technology advancing with a light fast speed though not everything coming to practical application and industrial production. Eliminating the power cord would make today’s ubiquitous portable electronics truly wireless. A number of researchers and startups are making headway in this growing field.
Wireless power technology transmits electricity to devices without the use of cables.
Now there was been talk of electricity manifestations all time into thermal, hydro, nuclear etc. In the later half of the 19th century electricity was lighting up streets and running fans, but the question what the best way for transmitting electricity was?
Imagining a vast infrastructure of wires extending into every city, street, building, and room seemed cumbersome and impractical. So here we had our mad dash Tesla figuring out that wireless transmission was the way to go. He drew up plans for a tower, about 57 meters tall, that he claimed would transmit power to points kilometers away, he then started to build one on Long Island. By the time his team did some tests, funding ran out before the tower couldn’t complete.
The promise of airborne power completely faded with rapidly industrializing world willed to wire up.
Now we had Marin Soljačić, an assistant professor of physics at MIT who was pulled out of bed by the insistent beeping of his cell phone. "This one didn't want to stop until you plugged it in for charging," exclaimed Soljačić. Exhausted state, he wished the phone would just begin charging itself as soon as it was brought into the house. So as it is technology discovered by the lazy, he started searching for ways to transmit power wirelessly.
Using radio waves was one option, which effectively sends information through the air, but the problem was that most of their energy would be lost in space.
More-targeted methods like lasers required a clear line of sight--and could also have harmful effects on anything in their way.
Instead of pursuing a long-distance scheme like Tesla's, he decided to look for midrange power transmission methods that could charge--or even power--portable devices such as cell phones, PDAs, and laptops etc.
So a method that was both efficient--able to directly power receivers without dissipating energy to the surroundings--and safe was sought.
The phenomenon of resonant coupling, in which two objects tuned to the same frequency exchange energy strongly but interact only weakly with other objects was used.
A classic example is a set of wine glasses, each filled to a different level so that it vibrates at a different sound frequency.
If a singer hits a pitch that matches the frequency of one glass, the glass might absorb so much acoustic energy that it will shatter; the other glasses remain unaffected.
Soljačić found magnetic resonance a promising means of electricity transfer because magnetic fields travel freely through air yet have little effect on the environment or, at the appropriate frequencies, on living beings. Working with MIT physics professors John Joannopoulos and Peter Fisher and three students, he devised a simple setup that wirelessly powered a 60-watt light bulb.
The researchers built two resonant copper coils and hung them from the ceiling, about two meters apart. When they plugged one coil into the wall, alternating current flowed through it, creating a magnetic field. The second coil, tuned to the same frequency and hooked to a light bulb, resonated with the magnetic field, generating an electric current that lit up the bulb--even with a thin wall between the coils.
Any low-power device, such as a cell phone, iPod, or laptop, could recharge automatically simply by coming within range of a wireless power source, eliminating the need for multiple cables—and perhaps, eventually, for batteries.
Incredible as it seems, the era of wireless world has arrived.
-NISHIT GURURANI
Computer Science Dept.
Email:nishitgururani@rediffmail.com
Bibliography: Technology Review by MIT
