So you might have heard of this little tech startup called Google. Well, it's got a new idea for a phone. But not just any kind of phone.

You see Google's looked around at the last six years of smartphone design progress, from practical but dull multi-ported devices to hermetically sealed handsets of pure beauty, and decided to throw it all away.

Instead, it wants your future smartphone to be modular.

Project Ara - Google's working title for the endeavour - was announced in October last year, to a fair bit of scepticism. 

Yet now that the first prototypes have been shown off, along with a lengthy document explaining how it will work, there’s a very good chance that this could be the most significant and popular of all Google’s hardware projects.

And given that this is the company which brought us self-driving cars, a photograph of every single square metre of almost every street on Earth, personal heads-up displays and universal internet access delivered by dirigibles, that's saying something.

So What is it?

Project Ara is a concept for a modular phone handset which Google says it will be able to get on sale in January 2015.

At its heart, an Ara handset is a simple metal frame known as an 'endo' (short for 'endoskeleton'). These come in three sizes – mini, medium and large – which have grids of 10, 18 and 27 square spaces on the back, arranged in groups of 1, 2 or 4.

The front of an endo accepts a removable screen, while modules will be available to fill the slots on the back. So owners can fully customise their phone by adding in a 4G modem, for example, or a 5GHz WiFi module, or removing things that they don't use such as a fingerprint reader.

More experimental phone owners might even look to add pico-projectors or remote controls, while the potential for adding in medical sensors for specialised use hasn't been overlooked either.

Why modular?

A fortunate accident just before the first Ara Developers Conference made the benefits of an Ara handset clear.

The night before the first functioning prototype was due to go on stage for its debut, someone dropped it and broke the screen. But, as Project Ara head Paul Eremenko joked during the presentation, once the phone is on the market, it'll be a simple matter to replace the screen by swapping out the front module for a new one.

The same is obviously true for any other modules - if you're a big photography fan, and a new camera module is released, you'll be able to upgrade your phone without getting a whole new body; if you're a power user and want extra battery life, just add another one.

The Ara team say that this means less waste, and since parts can be updated rather than thrown away the average lifespan of a phone will increase from two to five years. The downside, of course, is that modular components may end up costing more than a mass produced all-in-one (although Google is aiming to produce a basic handset for a very reasonable US$50) and may not be as robust.

Update 10/11/14: Android Central has shown off new shots of Project Ara in the flesh, showing off its modular design and individual components in greater detail.

While the prototype is able to run Angry Birds (hooray!), it's not on the latest version of Android, although that will obviously change when (or if) the finalised product ever lands on shelves.

Beyond the handset

One great thing about Ara is that all of the designs are open and free (as in libre, not gratis). As with Google's Android software, anyone can take Ara as a base design and suggest improvements or build their own compatible hardware. Well, in theory; we'd never be brainy enough to do that.

That makes the Ara handset spiritually akin to the Arduino microcontroller which has revolutionised everything from 3D printing to home automation to unmanned drones, and means it's almost certain to get the attention of the hacking community. One designer has already proposed a gamepad based on Ara endos.

Where will I get modules?

The plan is to sell modules via Google Play at first, but if Ara takes off anyone with a 3D printer will be able to manufacturer or customise module designs - particularly useful for filling unused module spaces.

And since custom phone skins have always been popular, they'll likely be on sale next to Beefeater teddy bears at a tube station near you before long.

Update 23/10/14: As reported by AndroidCentral, Google's Paul Eremenko has revealed that the company also plans to sell Ara modules in a dedicated online shop similar to the Play Store. Third-party Ara module creators will be able to sell their wares direct to customers through this (as yet unnamed) site.

Update 29/10/14: Google has filed an application with the United States Patent and Trademark Office to trademark "Ara"; suggesting that it may have settled on it as the final name for the product. That's a bit unusual; in the past, Google's tended to rename its devices once they're past the development stage, though there's plenty of time for it to change its mind. 

Is it really possible?

For many years, companies have been convinced that modular computers were the next big thing. We've had external graphics cards, external sound cards and external hard drives, with varying degrees of success. Those that failed did so because they were expensive and unreliable, but if any company can surmount those two challenges, it's Google.

With two more developer conferences planned for July and September, we're expecting plenty more news on Ara before its January 2015 arrival. Keep checking back here for regular updates as we get them.

Update 30/10/14: Phonebloks creator and modular smartphone cheerleader Dave Hakkens has paid a visit to NK Labs in Boston to see a working prototype of the Project Ara Spiral 2 handset in action. The first prototype, Spiral 1, is a rather chunky affair, but Spiral 2 is far closer to the modular concept design seen in the early Project Ara renders.

The Spiral 2 demo unit, which uses specially-designed Toshiba chips, can be seen in the video above; it's shown running Android OS, opening apps and swiping between homescreens. The Spiral 2 will be shown off in the flesh at the Project Ara developer conference in January.

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