Power, without the wires

Power, without the wires
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Can you imagine a world without power cords It’s almost here as Ashton Mills investigates.

Walking into your friends self-titled ‘Room of Pwnage’, you plonk your oct-core 9900 XXGTXX-based laptop, with extensible folding 24” screen onto his desk. Immediately, a small LED glows indicating there’s power, and you fire up the machine for Command & Conquer 5: Revenge of Yuri’s Tiberium Generals for some serious strategising. Before you get settled, you pull out your phone and iPod Microscopic and place them on a nearby bench and, as with the laptop, a little glow from the screens lets you know the batteries are now charging.

And there’s not a wire in sight.

It’s the magic of wireless power, and while it sounds science fiction-ish, it’s actually already here now – well, at least the beginnings.

How so?
We’ve grown up with wires and cables around computing – from power to SATA to networking and more. It’s the natural order of things – electrons need a medium to travel, and wire is it. Everything we use and everything we have, in terms of computing and gadgets requires wires. That’s just the way it is.

Only we used to think the same about the telegraph until radio waves were exploited, and then suddenly we had communication across continents without wires at all (the first successful trans-continental radio message was between England and France in 1902).

Today wireless communication abounds – and it’s here the crux of wireless power lives. If we can transmit data over the airwaves, why not power?

Looking to the past
The idea of transmitting power wirelessly isn’t new. In fact, it’s rather old. Nikola Tesla, who you’re probably familiar with in terms of his Tesla coils, used the same principles in an attempt to transmit power through air with the Wardenclyffe Tower, effectively a giant Tesla coil that began construction in 1901. The tower’s primary purpose was wireless communication, but Tesla had a dream of using it also to transmit power around the world with just handful of them placed around the globe.

Unfortunately for Nikola – who eventually died in relative destitution – funding for the tower dried up and it was never completed.

Today our understanding of electromagnetism and the fundamentals Tesla played with is more advanced, but it’s thanks to Tesla’s pioneering efforts that we have technologies like radio (Tesla is credited with the invention, although Guglielmo Marconi was said to have invented it first), the induction motor (we’ll get onto this in a moment), and alternating current (AC) which effectively revolutionised the world.

But it’s the age-old idea of wireless power that still sparks (pun) the fascination of the world’s new inventors. There are already products available that offer wireless power – at least for small devices – but it’s still a developing area of technology with a long way to go.

Today, there are a number of forms of wireless power being developed.

Do you remember you Scalerlectrix race cars as a kid? Or electric train sets, and remote control cars? All of these use electromagnetic induction to drive tiny motors (‘induction motors’), and is the same principle that powers the fans in your PC or the motor in your fridge.

At its simplest, electromagnetic induction is the process of generating an electric current from a conductor in a changing magnetic field or, just as useful, the reverse. It’s the application of a current to wire coiled around magnets that creates a fluctuating magnetic field for an induction motor which, in turn, can drive a rotor to create motion.

This leverages the property of the magnetic fields created whenever electricity flows through a wire. Coiling the wire amplifies the effect.

Any other conductor within this field will induce a current, and so in what’s known as inductive coupling two coils can be brought close together, but without touching, and induce a current in one coil when current is applied to the other – effectively wireless power, and the same process that allows transformers to work.

It’s all good, except it’s very short range. Higher voltages or larger coils can increase the range, but a lot of the energy is wasted in the expanding magnetic field.

Today a company called Splashpower already makes a product called the Splashpad that is essentially a powered coil loop which, when a compatible device is fitted with a similar loop and placed on its surface, induces an electric current so the device can charge. There are a number of advantages to this system, not the least of which is that you can charge multiple devices at once on a single pad. Currently the devices can’t charge laptops, although technically it would be possible if the induction could be made more efficient.

Speaking of which...

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This feature appeared in the July, 2007 issue of Atomic Magazine

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