Imagine if your smartphone was as advanced as your toothbrush — at least in the charging department. That would be cooler than your peppermint toothpaste.

If you've got one of those high-end vibrating toothbrushes, or any of several waterproof electric shavers, then you already own a device capable of a neat trick called wireless charging.

When you put that toothbrush in its charging cradle, you'll notice that no metal contacts are exposed for the electricity to charge the batteries. The toothbrush charges magically, right through the plastic.

Don't look now, but that very same technology is coming soon to your mobile phone, your iPod — even your laptop. 2007 is the year that truly mainstream wirelessly charging products finally go on sale.

How it works

There are three basic technologies for wireless charging: radio, resonance and induction.

Radio charging is well-suited for charging low-power devices at long distances — some 30 feet away. This technology is ideal for trickle-charging advance RFID chips affixed to, say, palettes loaded with products in a warehouse.

Resonance charging makes sense for robots, cars, vacuum cleaners and other applications that require massive power over minute distances — essentially making contact with plastic, but not metal.

Toothbrushes now, and random gadgets will very soon, use inductive charging. This technology uses a coil to create an electromagnetic field across a charging station surface. The device then converts power from the field back into usable electricity, which is put to work charging the battery.

(Meanwhile, researchers at US-based MIT said they have come up with a way to wirelessly supply power that could lead to the development of gadgets that don't require batteries at all.)

Where wireless charging gadgets come from

Wireless charging gadgets will come from some well-known companies, including Apple and just about every mobile phone handset maker, as well as small startups you may not have heard of.

An Apple patent submitted in 2005 and published in February describes technology for charging an iPhone or an iPod using zero-contact induction for not only charging but data transfer — an arrangement that requires inductive coils in both base station and device. Apple's patent covers both single coil (charging only) and two-coil (both data and charging) approaches.

Optimists speculate that Apple's inductive data-transfer technology might be used for synching, say, songs on an iPod or an iPhone. But pessimists, including Yours Truly, fear the main purpose might be locking out non-Apple products from getting in on the easy charging, or preventing users from charging Apple devices on non-Apple chargers. Apple devices may need to give the secret handshake before Apple chargers give up the juice.

Motorola, Japan's NTT DoCoMo and many other companies are very close to rolling out mobile phone handsets that use wireless charging.

Even US furniture maker Herman Miller is getting into the wireless charger business. The company has reportedly licensed eCoupled technology from Fulton Innovation, which it may build directly into desks.

A British company called SplashPower has come up with technology that can charge multiple devices at once by simply placing the gadgets on a mousepad-like surface. SplashPower has announced products called Multi SplashPad and Single SplashPad. The devices require a thin, inexpensive module inside the device for the charging to work.

Another company called WildCharge has products that work much like those from SplashPower. WildCharge unveiled two wireless charging products at the US CES 2007: The WildCharger and the WildCharger-Mini. The WildCharger is strong enough to charge laptops, in addition to mobile phones and media players, while the "Mini" version handles only the smaller devices.

Both WildCharge and SplashPower have been announcing and demonstrating their products for years. Neither has publicly announced a definitive ship date, but a WildCharge representative told me it will start selling products on its Web site on July 9.

What's so great about wireless charging?

Obviously, wireless charging gadgets are ideal for the extremely lazy, which is why I personally am very excited about all this. Just dump your device on a pad, and you're good to go.

But the technology provides a wide range of other obvious and not-so-obvious benefits, including better portability, lower cost (once companies can assume everyone already has a universal charger) and — best of all — the end of having to guess which chargers go with what gadgets.

I believe it's a no-brainer that hotels will eventually provide charging pads in rooms. Everyone will have pads here and there around the house. Charging will one day become a simple matter of dropping devices onto the nearest charging pad.

Wireless charging means the end of charging connectors that break, wear out or become misaligned.

A single charging pad will be able to juice all your gadgets, so you won't have to match this charger with that gadget, or replace an overpriced charger when you lose it.

It also makes it easier to build mobile devices that — like your toothbrush — are waterproof, dustproof and more rugged.

The technology makes wireless gadgets truly wireless — at last.

Today, wireless charging appears to be the vapourware category of the year. But some time very soon — very soon — your mobile phone will finally catch up to your toothbrush in the wireless charging department.

The toothbrush will whiten your teeth, but wirelessly charging all your gadgets will make you smile.

Mike Elgan writes about technology and global tech culture. Contact Mike at mike.elgan@elgan.com or his blog, The Raw Feed.