Motion-sensing game controllers

Overview
Current-generation game consoles are all out to offer the best motion-sensing game experience available. We explain what each has to offer.

What's wrong with a good ol' joypad?
Throughout the 80's and 90's, the preferred method of input for the majority of games consoles continued to be the tried-and-trusted joypad. Despite the fact that joypads have remained as the de facto input standard for current-generation consoles such as Microsoft's Xbox 360 and Sony's PlayStation 3, they face an increasing threat from motion-sensing controllers.

Even though the technology for motion-sensed input has been available for many years, the control method first showed signs of becoming mainstream in 2006 with the launch of the Nintendo Wii console.

Unlike rivals Sony and Microsoft, Nintendo opted to take a different approach to gaming and has since reaped the benefits. Its motion-sensing controller, dubbed the Wii Remote and bundled with each Wii console, has become hugely popular with both new and existing gamers due to its pick-up-and-play nature. It is often cited as the primary reason for the Nintendo Wii's prominent lead as this generation's biggest-selling games console, having sold over 50 million units.

What's the appeal?
While there's nothing inherently wrong with a joypad - and we all still love a bit of button-mashing - the general consensus is that joypads are primarily accessible to users familiar with gaming. With profits in mind, the goal for the likes of Microsoft, Nintendo and Sony is to get everyone and anyone gaming.

A motion-sensing controller, therefore, is better suited to gamers of all ages, and, as the Wii Remote has shown during its first few years on the market, there's plenty of appeal for those who've never gamed before. With Nintendo capturing a massive market of 'casual' gamers, both Microsoft and Sony - whose current-generation consoles have largely targeted hardcore users - are hoping to one day claim their slice of the casual-gaming pie. How will they do it? Well, the plan is to follow in the footsteps of Nintendo with motion-sensing devices of their own - only, with a twist.

In June 2009, at a major annual games conference, both Microsoft and Sony unveiled upcoming motion-sensing devices that are expected to make their debut on the Xbox 360 and PlayStation 3, respectively, in 2010.

So, let's take a look at all three offerings, finding out how they work, and what they offer.

Nintendo Wii Remote
The Wii Remote - also known as the WiiMote - which you've no doubt seen, or even used, is bundled with Nintendo's Wii console and acts as its primary controller.

Its unique ability to detect motion and act as a pointing device is made possible by a combination of modern-day technologies. It might be about the same size as a regular TV remote, but there's plenty happening in this little device.

First and foremost, the Wii Remote needs to be able to detect where a user is pointing, allowing for users to click on certain areas of a screen - similar, in a sense, to how a mouse cursor is used to navigate a computer. In the case of the Wii Remote, this is achieved by a sensor-bar equipped with a series of LEDs and an optical sensor built into the remote.

The Wii Remote's built-in optical sensor acts like a camera used to locate the sensor bar's infrared LEDs in its point of view. By plotting where two spots of light fall (one from each end of the sensor bar), the Wii console is able to determine where the remote is pointing in relation to the screen.

All sounds very clever - and it is - but it does have some drawbacks, too. A user, or indeed multiple users, would need to remain within the sensor bar's point of view in order for the system to work.

In addition to knowing where a user is pointing, the Wii Remote can also calculate how it's being moved. This is done with the use of accelerometers - tiny chips that feature a piece of silicon anchored at one end and allowed to move at the other between an electric field created by a pair of capacitors. Accelerating the remote in one direction causes the silicon to move and disrupt the electronic field. That change is translated to motion, and the Wii Remote can measure acceleration on three axes - allowing for the ability to perform a variety of gestures such as moving side to side, twisting, and pushing and pulling.

On top of all that, the data captured by the optical sensor and accelerometers needs to be sent back to the Wii console without wires. In order to achieve that, the Wii remote contains a built-in Bluetooth chip that allows for two-way communication with the console.

Sounds brilliant, and it is, but hardcore gamers have argued that the Wii Remote isn't completely accurate, and doesn't offer as precise control as say a joypad. Hoping to increase the accuracy of the remote, Nintendo in June 2009 launched an expansion device dubbed Wii MotionPlus.

The optional accessory, plugs into any existing Wii Remote and features a multi-axis gyroscope that, when combined with the accelerometer and sensor-bar, should offer a far more accurate tracking mechanism.

That's the Wii remote, and it has thus far set the standard for motion-based games control. Nonetheless, both Sony and Microsoft think they will top it in 2010.

Sony PlayStation Motion Controller
In-the-know readers will be aware that Sony's PlayStation 3 console launched with a motion-sensing controller back in 2006. The peripheral, dubbed the SixAxis Wireless Controller, is essentially a DualShock joypad equipped with sensors that allow it to track movement along the three posture axis of roll, pitch and yaw, as well as three-dimension acceleration information along the X, Y and Z axes.

The SixAxis was deemed by many in the media to be a last-minute attempt to scupper Nintendo's Wii Remote. It has so far failed to gather widespread interest from game developers and its use for motion detection has become something of a rarity. The SixAxis was later succeeded by the DualShock 3, a similar joypad with added rumble functionality.

Trying its hand at the motion-sensing game once again, Sony will next year launch its second attempt in the form of a PlayStation Motion Controller.

Not a whole lot is known about the device, and it doesn't yet have a finalised name. Sony, however, has publically stated that the controller will be available in spring 2010. As of now, we've only seen it demonstrated in prototype form. So, what do we know so far?

The PlayStation Motion Controller prototype is a handheld device similar in size to the Wii Remote and it's quickly becoming known as "the wand" due its illuminated orb.

As it turns out, that orb is key to the controller's functionality. It's equipped with LEDs that are able to shine in a variety of colours, and it's those spherical colours that are tracked by the controller's accompanying component - the PlayStation Eye.

Unlike the Wii Remote - which, remember, uses a infrared light-emitting sensor-bar to track position - the PlayStation Motion Controller will be detected by the PlayStation Eye webcam. Due to the spherical shape of the controller's top, the webcam is able to determine its position and distance by tracking the size of the sphere in relation to itself.

With the orb allowing for the 'wand' to be tracked in three dimensions, Sony's controller then uses additional WiiMote-like technology to sense motion. Although Sony is yet to detail the finer workings of the controller, early indications suggest that the device is equipped with accelerometers and multi-axis gyroscopes that offer motion-tracking functions similar to the Wii MotionPlus.

At the prototype stage, Sony's PlayStation Motion Controller appears to be more evolutionary than revolutionary, but the promise of 'high-precision, sub-millimeter' accuracy should be far more appealing to developers than the lacklustre SixAxis.

That leaves Microsoft, so let's see what it has to offer.

Microsoft Project Natal
Microsoft's attempt to reach out to the vast casual gaming audience has taken on a unique form. Although motion-sensing remains a key ingredient, Microsoft hopes to create a gesture-based experience without the need for users to hold any form of peripheral.

Sounds bold, but it reckons it can do it with a piece of kit codenamed "Project Natal".

In its simplest form, Project Natal (pictured right) is a horizontal peripheral measuring roughly 25cm. It's designed to sit below or above a television screen and connects to an Xbox 360 console. Once connected, it will spot human presence via facial recognition and allow users to control both the Xbox 360 interface and games using gestures or voice commands.

Sounds promising, so how does it do it? Inside Project Natal are a number of components that come together to deliver the full experience - including a webcam and multi-array microphone, a depth sensor and a processor running proprietary software.

All seems a bit complicated, but putting it simply, Project Natal emits an array of beams that hit objects in its path and bounce back to the device. With the data returned, the on-board processor's proprietary software is able to map a surprisingly accurate image of everything in its field of view.

Exactly how accurate? Well, irrespective of objects in a room - including, for example, a couch - Project Natal is able to map the full body of multiple players, with project director Kudo Tsunoda suggesting that it could track a user's individual fingers depending on distance from the device.

The theory is that a user is able to walk in front of their console, be instantly recognised, and be able to control the system and it games by moving parts of their body in a 3D space mapped by Natal.

Is it too good to be true? Although Microsoft has publicly shown Natal tech demonstrations, it remains to be seen how well it can be implemented in real-world usage. However, game developers have already shown a keen interest, and Project Natal has quickly become the focus of media attention. It's expected to become available in 2010, but despite its apparent technological advantage, we'd assume it would be more costly to produce than, say, a Wii Remote or a PlayStation Motion Controller, and that may be Natal's biggest obstacle as it attempts to lure a casual-gaming audience in the midst of a recession.

Summary
The age-old joypad continues to live on as the preferred input method for the experienced gamer, but following the pioneering efforts of Nintendo, motion-based control looks set to become a key gaming element in the coming years.

With all three of the biggest games console manufacturers pushing the technology forward, both casual and hardcore gamers alike can expect to be faced with multiple motion-sensing controller choices in the near future.