How PlayStation Move Works

PlayStation Move, E3
A screen announcing the Sony PlayStation Move at the E3 (Electronic Entertainment Expo), held earlier this year in Los Angeles. See more video game system pictures.
Doug Kline @

Video games sure have changed a lot in the past 30 years -- but, strangely, the way we interact with them hasn't changed that much at all. In the 1980s, the Nintendo Entertainment System helped cement a control scheme that has endured to this day: a small controller, held in both hands, with one thumb resting on a cross-shaped control pad and the other hovering over a pair of raised buttons with A and B on them.

As games evolved, so did controllers. They added extra buttons for more actions, triggers for our index fingers to rest on and finally joysticks to better control 3-D movement. Ergonomically, controllers have differed quite a bit -- but when it came to functionality, they were about the same. That is, until the Nintendo Wii came along, reinvented the controller and sold boatloads of systems.


The Wii focused on controlling games with motion and pointing at the TV. Its controller looks far more like a television remote than a typical game pad, and this new form of control has helped Nintendo sell nearly 74 million Wiis worldwide between November 2006 and July 2010 [source: Alexander]. Sony and Microsoft have been scrambling to tap into the Wii experience -- but how do they beat Nintendo at its own game?

In September 2010, Sony launched its own motion control system, the PlayStation Move, compatible with its game console the PlayStation 3. Just like the Wii, the PlayStation Move comes with a pack-in sports game. Just like the Wii, the PlayStation Move controller looks a bit like a weird TV remote. Sony hopes a special camera and a unique system of 3-D positioning will help the PlayStation Move outmaneuver Nintendo. In this article, we'll explore how.



PlayStation Move on the Outside

PlayStation Move, E3
A closeup of some of Move's features.
Doug Kline @

PlayStation is a well-established brand, and Sony played it safe with the overall design of the Move by closely adhering to an aesthetic gamers would recognize. Like the PlayStation 3 controller, the Move remote is matte black plastic, with four small face buttons near its top bearing the familiar PlayStation symbols: X, O, square and triangle. The four small buttons flank a larger center button marked with the Move logo.

The Move controller's slight hourglass shape and button placement help guide the user's hand into place, since the thumb is meant to rest over the center Move button. Since the PlayStation Move is all about motion, it can get away with fewer in-game actions springing from button presses; hence one dominant, large button.


The final button on the face of the controller bears the PlayStation logo and can sync the controller to the console and access the PlayStation 3's dashboard. The typical start and select buttons for pausing and options rest on the sides of the controller near the top. Finally, on the back of the device is a concave trigger (appropriately marked with a T) for gamers to cradle with an index finger -- perfect for first-person shooters or any motion control trying to simulate a hand grip [source: Mikhailov].

Of course, there's the impossible-to-overlook sphere resting atop the Move wand. It even glows! As we'll explain in the next section, that glowing ball is actually what allows the PlayStation eye camera to track the controller's movement.


The PlayStation Eye and That Big Glowing Ball

PlayStation Move, E3
Some gamers trying out the Move at E3. Note the glowing ball.
Doug Kline @

Attaching a bulbous, glowing sphere to the top of a device is one way to make it stand out, but the PlayStation Move's ball isn't just for looks -- it's actually an integral part of the controller. Working in tandem with Sony's PlayStation Eye camera, which comes included with the Move bundle, the ball allows for 3-D motion tracking in real-time.

Inside the ball is an RGB LED, which means the sphere can light up with practically any color. When multiple Move controllers are used simultaneously (the PlayStation 3 supports up to four at once), it's easy to tell them apart by the color of the sphere.


The ball's primary function, however, is providing a visual reference for the PlayStation Eye. The PlayStation Eye is a USB camera that plugs into the PlayStation 3 system and captures video at a resolution of 640x480 at 60 frames per second. Those specifications translate into a very quick response time, meaning actions the PlayStation Eye perceives are displayed on the screen with minimal delay or lag [source: Sony].

Things get interesting when the Move comes into play: The PlayStation Eye has been programmed to recognize the exact size and shape of the ball on top of the Move remote. Once the Move controller is visible to the camera, it's able to detect the exact positioning of the ball in 3-D space. By tracking the size of the ball (and easily following it, thanks to the glowing LED) the PlayStation Eye can accurately tell where the ball is at any time.

In addition to tracking the ball's coordinates, the PlayStation Eye can identify human faces and perform head tracking -- once it recognizes the people in front of it, the Eye can accurately follow the movements of their heads, but not quite as accurately as following the Move's sphere -- after all, people don't come in an exact size and shape! This entire process can be carried out within the span of less than one frame of movement (out of 60 per second) thanks to the power of the PlayStation 3's processor [source: Joystiq].

The video interface isn't the Eye's only ability. It can also pick up audio via an array of four microphones. Primarily, though, the Eye's task is keeping up with the Move remote's location. But location only paints half the picture -- it takes a whole other mess of sensors to interpret the orientation and movements of the Move, and they're all packed tightly into the controller itself.


Move's Methods of Communication

Like most video game controllers released over the past decade, the PlayStation Move includes a built-in rumble feature. The Move controller uses haptic feedback to vibrate. Just like the regular PlayStation 3 controller, the Move connects to the system with wireless Bluetooth technology. The Move also features a rechargeable battery that can be connected to the PS3 and charged via a mini-USB port on the bottom of the controller. Unlike the Wii Remote, the Move controller does not include a speaker to provide auditory feedback during games (other than through the television, of course). Sony considered including a speaker, but ultimately decided that its limited benefits were outweighed by the added cost [source: Mikhailov].

Unfortunately, there's a drawback to the PlayStation 3's Bluetooth support: It can only connect to a total of seven wireless devices. With that restriction in mind, Sony limited Move to a total of four devices -- four Move remotes, or two Move remotes and two Navigation controllers (see sidebar), which offer more traditional analog stick-based inputs alongside the Move. Allowing up to four players to each use two Move controllers or an additional Navigation controller would have required support for eight units connected via Bluetooth [source: Wilson]. This means that some games, which offer enhanced features when played with a Move controller in each hand, will work with no more than two players.


PlayStation Move Games

playstation move, E3
Some gamers enjoying LittleBigPlanet 2 at E3.
Doug Kline @

Twelve games were released alongside the PlayStation Move during fall 2010, with a total of 31 games supporting the system by the end of the year [source: PRNewsWire]. Sports Champions, much like Nintendo's Wii Sports, will come bundled with the Move and includes six sports games that demonstrate the Move's capabilities.

Some games, like Sports Champions and Sony's Eye Pet, are specifically designed for the Move. Others, however, will offer traditional control options in addition to supporting the Move. Upcoming games like Resident Evil 5 Gold Edition, LittleBigPlanet 2, and SOCOM 4 are built upon established franchises that gamers have already played with regular controllers. The Move will offer a new way to play these games, but they won't be completely reliant on motion controls.


Sony's first-party games released exclusively for the PlayStation Move are priced at $39.99, which is $20 less than the majority of games released for the Xbox 360 and PlayStation 3. Few games have been announced for the Move for 2011, but the third entry in Sony's first-person-shooter franchise Killzone will support Move controls.

Of course, Sony won't be the only company putting brand new motion control games on store shelves this holiday season. On Nov. 4, 2010, Microsoft will release their motion control system Kinect. And even though both Sony and Microsoft are trying to add motion gaming to their consoles, the two systems are surprisingly different. Let's take a look.


PlayStation Move vs. Microsoft Kinect

Microsoft's Kinect, an add-on for the Xbox 360 console, is a bit like Move -- but without the controller. Microsoft opted to completely eliminate any kind of direct input device and instead base gameplay completely on body movements. Think of Kinect as a camera like the PlayStation Eye, only with no controller (or glowing ball) to track.

The Kinect's camera uses an entirely different technology from the PlayStation Eye. Kinect actually houses two cameras. One, a typical color camera, is used for face tracking and taking pictures, while the other, a CMOS camera, works with a device that beams invisible infrared light into the room. The camera picks up and analyzes the infrared light to detect objects, and can accurately judge where those objects (like people!) are in 3-D space. The Kinect has also been programmed with a wide variety of human gestures and knows our bone structure. It performs skeletal tracking to follow our every arm wave and awkward hop [source: Miller].


While the Move remote can be used the navigate menus on the PlayStation 3's dashboard, Kinect offers a hands-free gesture system to control the Xbox user interface. It's a neat touch, but some gamers are worried about the gaming experiences Kinect can offer with no joysticks or buttons in sight.

In the end, controlling a console's user interface is merely a side benefit. Making fun, interactive games is the real goal, regardless of the control method. Sony's PlayStation Move tries to offer the best of both worlds: buttons and accurate motion tracking for the hardcore gamers, and appealing software for newcomers. With Move and Kinect as challengers, Nintendo no longer has solitary control of the motion-gaming market -- but it's up to game developers to tap into the potential each platform has to offer.


Lots More Information

Related Articles

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