IT TRENDS
Doing away with the power cord
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A technology is on offer to wirelessly charge your mobile phone
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PHOTO: M. VEDHAN
UMBILICAL CORD: Laptop connected to a power source using a power cord.
SAY HELLO to WiTricity — wireless electricity. Two weeks ago, a group of six researchers from the departments of Physics, Electrical Engineering and Computer Science at the Massachusetts Institute of Technology (MIT), U.S., posed for an unusual group photo.
They stood or sat between two large copper coils, about half a metre in diameter. One of the coils was connected to a source of electric power. To the other, a 60 watt light bulb was attached. When the power switch was thrown on one coil, the bulb connected to the other glowed — across a wireless gap of about 2 metres.
Successful transfer
It was a demonstration that electricity could be transferred without having to use wall sockets and power cords — albeit across short distances — by coupling two magnetic fields that resonated at the same frequency.
The researchers headed by Marin Soljacic, professor of Physics at MIT, called their technology WiTricity — wireless electricity — and published early details of their work in a recent issue of Science Express, the online
edition of the journal, Science. ( http://www.sciencemag.org/cgi/content/abstract/1143254 ).
Improving efficiency
The copper coils in the experiment worked at just 45 per cent efficiency, but the MIT scientists are confident they can improve this to around 80 per cent.
The transmission of electricity using objects that vibrate at the same frequency when coupled magnetically is not a new idea. It was first proposed in 1893 by the Austrian-American inventor Nikola Tesla (he gave his name to the unit of magnetic induction) — but he lacked the infrastructure to turn it into a practical application.
Why is the idea of electricity without wires popping up again after all these years? Because in today’s converged, connected world, we tend to use dozens of different gadgets — mobile phones, portable computers, digital still and movie cameras, music players — all of which run on rechargeable batteries. We know what a hassle it is to mate the right device to the right charger — no two makes of mobile phone seem to accept the same charger — and we end up carrying a cat’s cradle of jumbled chargers and wires.
If only we could charge all these devices without needing to connect wires to power sockets! This fervent wish list is the trigger for the current flurry of research in wireless electric transfer.
While MIT is working on the more heavy-duty potential of WiTricity, others have already come to market with low energy solutions that specifically address the need to recharge multiple personal devices at one go. Two Cambridge University (UK) graduates — James Hay and Lily Cheng — pooled their resources soon after they graduated in 2001 to start a company — Splashpower ( www.splashpower.com).
Shackles removed
“It’s not about giving you more technology, it’s about freeing you from the hassles of the technology you already have.” With this in mind, they have developed a convenient new way of powering mobile phones and other portable electronic devices without wires. They have created SplashPad — it looks like a large ash tray with a power connection. On this, you can place multiple mobile phones, pocket PCs, and other devices that need charging. Electromagnetic induction is harnessed to trickle–charge them at the same rate wired chargers normally work.
The same principle also drives the range of ‘3-Coupled’ wireless chargers for the car offered by the Michigan (U.S.)-based Visteon Corporation and based on inductive coupling technology created by Fulton Innovation ( www.ecoupled.com). It was demonstrated for the first time in January this year at the Consumer Electronics Show in Las Vegas.
Gartner recently listed eCoupled among the year’s 12 cool new technologies, in its annual survey of emerging trends.
When the industry monitors notice such trends you can be sure, money will follow the trail, fuelling the applications that will soon percolate to lay consumers and have them say: “Cut that cord. I have wireless power.”
ANAND PARTHASARATHY
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