Get Ready For Wireless Power


We live in the era of wireless devices. Satellites, cell phones, laptops, Wi-Fi, Bluetooth, 2G, 3G, 4G—we have an entire arsenal of totally mobile devices which we can rely on to serve our hefty appetite for technology, absolutely wireless.

Until the dreaded low-battery signal starts its nerve-wrecking beep. Then we remember how we still depend entirely on wires to power our technology.

Our flawed system of satellites, batteries and antennas allow us to drag around our not-entirely-mobile devices everywhere we go, and to exchange data “wirelessly” for increasingly longer periods of time. However, sooner or later, our uncharged devices start their insistent indicator lights and panicked beeping, and just like a toddler suffering from separation anxiety, they require to return to their mother cord.

However, what if we can give away with the tangle of power cables messing around our living room floor? What if we can throw away our batteries and say goodbye to the hassle of plugging, charging, and recharging that hinders our transfer to a truly wireless world?

MIT Professor Marin Soljacic and his team, along with several power companies believe that we can. They say now is the time to do it.

As exciting the new age of technology of wireless power may seem, it is really a principle that is over one hundred years old, originally developed by Nikola Tesla and demonstrated by his famous “Tesla Coil Tower”, a device which he used to beam energy across great distances.

Few believed that Tesla’s coil would work, and to be fair to the doubters it did not, at least not how it was supposed to work. For although his coil was able to eliminate lamps from across the room, it also shot 40 meters long bolts of electricity at passersby and made the ground around it glow blue with high voltage current. It was also highly inefficient, which is why his work was eventually abandoned, although his concept for wireless electricity—electromagnetic conduction—was in fact, spot on.

A magnetic field is created when an electric current is passed through a coil of wire. Conversely, an electric current is created when a coil of wire is passed through a magnetic field. Harnessing this phenomenon, it is possible to transfer energy wirelessly by creating a powerful magnetic field using a base station of coiled wire connected to a wall socket, and a receiver made of a coiled wire connected to an electronic device. It is the same concept that we apply to charge a wireless electric tooth brush, and it works well over extremely short distances.

Professor Soljacic and his team are still working on the same principle, only they added a small physics trick to make the energy transfer more targeted and efficient, and to make it work over much longer distances.

Their trick is known as “Magnetic Resonance”, and it is similar in concept as to how an opera singer shatters glass from across the room: when the frequency of the sound wave matches the unique resonance frequency of the glass.

By tuning the base station magnet with the receiver magnet to resonate at the same frequency, the MIT team was able to create an electrical charge in specifically-tuned receivers, and no charge in others—effectively targeting energy transfer (in open rooms and around corners) and making all other objects in the house—even other magnets—unaffected.

Several companies are now working on bringing wireless electricity to our homes, and they assure us that the day when we cut the cord tethering us to the wall is very soon.


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SCIplanet is a bilingual edutainment science magazine published by the Bibliotheca Alexandrina Planetarium Science Center and developed by the Cultural Outreach Publications Unit ...
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