How the Nintendo 3DS Works

Compare the 3DS to an older DS or a DS Lite and you'll see it's a bit bigger, thicker and heavier than its older siblings. But the Nintendo DSi XL remains the biggest kid on the block. Here's a rundown on the physical features of the 3DS:

The 3DS shares many of its predecessors' features. You can download games over WiFi or buy physical cartridges for the 3DS. It has an 802.11 WiFi connection as well as Nintendo's proprietary WiFi service. It has a microphone that lets you record sounds for playback -- it also comes into play with some games where sound is an interactive part of the experience. You can store information on an SD card and even transfer content like music and photos to other devices, though there are some limitations on the content you can share.

The 3DS has a standard 3.5-millimeter headphone jack, and a physical sliding control for volume. There are also sliders to control the 3-D effect on the upper screen and a switch to turn the WiFi on or off. On the back of the device, you'll find a storage space for the 3DS's telescoping stylus, a port for the 3DS's AC charging cable and an infrared transceiver panel.

Like the other members of the DS family, the 3DS has a resistive touch-screen display. That means the screen reacts to pressure. Inside the display are two special layers that detect touch. One layer is conductive while the other is resistive. When the two layers come into contact with each other, the 3DS detects the change in the electrical field and interprets the touch as a command. Technically, any pressure on the screen will work but Nintendo warns users to limit themselves to using the official Nintendo stylus with the touch-screen display.

The stylus and touch-screen interface aren't the only way you can control games with the 3DS. It also has a direction pad, a new circle pad that can act as a joystick or camera control interface for certain applications, four controller buttons and dedicated buttons for home, start and select features. The control pad and buttons will look familiar to any Nintendo fan -- they have their roots in the old Super Nintendo Entertainment System controller.

The 3DS has three cameras. One faces the player. The other two are on the back of the 3DS -- you can use them to take pictures in 3-D. We'll dive into the three-dimensional world of the 3DS a little later.

You can get games for the Nintendo 3DS either buy purchasing game cards -- tiny cartridges -- or by downloading them through Nintendo's service. The 3DS is backwards compatible -- it can play game cards for the Nintendo DS and DSi systems. But don't expect those old games to take advantage of the 3-D capabilities of the 3DS. You'll be able to play them but they'll remain in 2-D.

Early reviews of the Nintendo 3DS criticize the loading time for old games. Part of the problem may be due to the fact that the 3DS has a different screen resolution than the DS and DSi. To compensate, the 3DS may need to take more time to adjust the graphic settings for a game before it can launch into gameplay.

Downloading a game will store the title on your 3DS's SD card. Each SD card can hold up to 300 titles. Nintendo is quick to point out that you don't actually own these games -- just a license to play them on your machine.

If the game is free, you may even send a copy of it over Nintendo's SpotPass service. This uses WiFi to let you distribute games to other Nintendo 3DS owners. The service won't allow you to distribute purchased games.

Nintendo has incorporated some digital rights management (DRM) strategies with the downloadable software. For example, if you copy a title from one SD card to put it on another, the title will stop working on the old SD card. This prevents Nintendo 3DS owners from making illegal copies of games and giving or selling them to other people.

Nintendo also includes parental controls on the 3DS to help parents limit the types of games and information kids can access when using the system. Since the 3DS has a Web browser, parents may want to turn on the parental control features to limit what sort of content their kids can see while online. And not all video game titles are family friendly -- the parental controls let you set what types of games will work based on their ESRB rating.

Next, we'll learn what gives the Nintendo 3DS its oomph.

We decided to take a close look at what makes the Nintendo 3DS tick. Unfortunately, this meant dismantling a device, which meant we immediately voided our warranty. We at HowStuffWorks.com are happy to do this so that you don't have to.

The Nintendo 3DS uses a proprietary ARM processor as the brains behind the device. Sharp manufactures the chips and it's not entirely clear exactly how much power the processor provides. Estimates range from 500 megahertz to 1 gigahertz of processor speed but Nintendo isn't offering clarification.

A Digital Media Professionals Pica 200 chip serves as the graphics processing unit (GPU). This allows the CPU to offload the burden of generating graphics to the GPU. The chip inside the 3DS runs at 400 megahertz.

That's not the only chip inside the 3DS. There's also the Fujitsu MB82M8080-07L chip, which provides 128 megabytes of random access memory (RAM) to the 3DS. A 1-gigabyte flash memory chip from Toshiba provides storage for the 3DS.

Other chips on the motherboard include one from Texas Instruments that controls power management for the device to extend battery life for as long as possible. There's an Invensense chip that gives the Nintendo 3DS its gyroscopic capabilities and an ST chip that acts as an accelerometer. Both of these chips allow Nintendo to design games that require you to move the 3DS around physically to perform tasks within the games themselves.

There's also a Mitsumi DWM-W028 board that provides WiFi capabilities to the 3DS. It incorporates an Atheros AR6014 IC chip. This is what lets the Nintendo 3DS communicate over 802.11 WiFi. There's also an antenna attached to the chip to improve reception.

Toward the back of the motherboard is a chip so tiny it's easy to miss -- the S750 IR control chip. This chip is in charge of the 3DS's infrared transceiver. Presumably, this transceiver will allow Nintendo 3DS owners to have their devices interact with one another in some way.

That's the guts of the 3DS but how does it manage to display 3-D images without requiring special glasses?

Humans judge depth using several visual cues. For people who have healthy, working vision in both eyes, one of those cues comes to us courtesy of binocular vision. Binocular vision makes stereopsis -- the technical term for 3-D vision -- possible. Here's how it works.

Assuming you've got healthy vision in both eyes, your optical fields overlap. That means if you were to close one eye and look forward and then switch eyes, much of what you'd see would remain the same. Both eyes collect light and send signals to the brain, which incorporates this information into a single image.

Our eyes converge upon points we focus on. The closer an object is, the more our optic axes converge to intersect each other. A scientist named Charles Wheatstone discovered that our brains can judge depth by comparing the differences between the two sets of images the brain receives from our eyes. These differences allow us to judge how far away an object is.

Wheatstone conducted some experiments that suggested our brains fuse the two streams of data we receive from our eyes into a single mental image. One of these tests involved a stereogram -- a pair of images -- of the same object at two different scales. If you were to view each image separately, you could tell the two weren't of the same size. But when viewed together with each eye only seeing one of the two images, the viewer's brain would fuse the two pictures into a single image. And that image's size would be between the large and small versions of the picture he or she was looking at.

Wheatstone also discovered that if a person has poor vision in one eye, the brain learns to dismiss the information that eye gathers. It's actually possible to develop the skill to fuse images from both eyes with concentration. That's how Magic Eye pictures work -- they require effort on the part of the viewer.

There are other cues we rely on to judge depth, including how large an object appears to be in relation to other objects within our field of view. But binocular vision is what makes 3-D imaging possible. By presenting each eye its own set of images, 3-D technicians can simulate what it's like to look at an actual, physical object.

So how does the 3DS take advantage of this?

There are different ways to do achieve a three-dimensional effect. Anaglyph systems use two different colors of light -- usually red and blue -- and special glasses that block one set of images to an eye while allowing the other set to pass through. Polarized systems have special glasses that only let light aligned a particular way to pass through to reach your eyes. And active-shutter glasses have tiny LCD shutters that open and close in a pattern synchronized with a display. Each eye only sees one set of images and your brain does the rest of the work for the system.

But what about the 3DS? It doesn't use glasses. The secret of the 3-D power lies in the parallax barrier. The 3DS screen has a special layer on top of it that helps direct light in a particular way. The layer is a second liquid crystal display (LCD) in which the crystals can create barriers that channel light. When you turn the 3-D mode off on the 3DS, the crystals allow light to pass through freely so that both eyes receive the same image. By moving the switch up, the 3DS adjusts the placement and width of the crystals in the parallax barrier, sending a different set of images to each of your eyes.

Your brain takes the two sets of images and incorporates them into a single picture with depth. One disadvantage of this method is that the 3-D effect only works for a relatively narrow viewing angle. If you were to hold the 3DS too far to the left or right, you would begin to see a double set of images, which can be disorienting. The same is true for anyone trying to watch you play a game -- they may just end up with a headache.

Because of the nature of the 3DS, most people will find it natural to hold the device at the right distance to get the 3-D effect. If the 3DS were a television set, you'd have to sit in just the right spot to get the three-dimensional effect. And developers must design games with two sets of images to take advantage of the three-dimensional display -- that's why older DS and DSi games won't show up in 3-D.

The basis of the parallax barrier is the lenticular display. You may have seen postcards or pictures that have a special ridged surface on the top. When you tilt the picture back and forth, the images appear to move. The ridged surface directs light reflected by the picture to your eyes. There are actually several images on that one picture, it's just the ridged display only allows you to see one at a time. By tilting the picture quickly, you create the illusion that the image itself is animated.

The two cameras on the back of the 3DS allow you to take 3-D photographs. Each camera captures an image. The 3DS combines the two images and displays them using the 3-D technology. You can store these images on an SD card. But don't expect to view pictures of your friends in 3-D on other devices -- they'll only be in 3-D on the 3DS.

Next, we'll look at how the 3DS can create a layer of games around you in the real world.

Back in the early 1990s, the term virtual reality became a buzz phrase. Two decades later, augmented reality appears to be following suit. The concept sounds like something out of a science fiction film -- using technology, we create an artificial layer on top of the real world around us. We fill this layer with everything from useful information to games. So while reality surrounds us, there is also a fantasy world generated by technology present.

The rise in popularity of smartphones has pushed research and development into augmented reality applications. There are smartphone apps that let you hold your phone's camera up to a restaurant in order to find out what the menu is like or how other people have rated the food, for example.

Nintendo pre-installs augmented reality software onto the 3DS. Fresh out of the box, you can play games that combine virtual elements with physical objects. Each 3DS comes with a pack of Nintendo cards. One of those cards has the familiar yellowish box with a question mark on it -- a staple in games like "Super Mario Bros."

Placing the card on a flat surface and activating the AR games menu item gets you started. The 3DS activates its rear-facing cameras. You point the cameras at the card. Once the 3DS identifies the card and judges your distance from it, you'll see a virtual, three-dimensional box pop up on the surface of the card as you look at the 3-D display.

You can interact with the virtual object in several ways. You can play a couple of different games that require you to move around and shoot virtual targets as you keep your cameras trained on the real card in front of you. There's also a program that lets you draw images, which the 3DS renders as an object with actual depth. It will look as if your drawing is standing up on the flat surface that supports the AR card.

Using both cameras, the 3DS can gauge the angle and distance of the card by comparing the two sets of images, much the same way as we perceive 3-D with our own eyes. As you move the 3DS around the card, the cameras detect the new angles and distances and the 3DS adjusts the rendering of the virtual objects to match the new position. Move too close or too far away and the 3DS warns you to adjust back to the optimal distance.

The AR games only work with specific images. You can't point the 3DS at a building and expect to have a virtual game pop up. The processors will only work with patterns they recognize, like the box with the question mark on it. If you lose the AR card, you can print out a replacement from Nintendo's Web site.

The operations manual for the Nintendo 3DS contains a section on potential health hazards users might encounter while playing the Nintendo 3DS. One of those is seizures. According to the manual, about one in 4,000 people may suffer seizures as a result of looking at flashes of light. This sensitivity tends to decrease if the viewer is farther away from the source of light but with a handheld device that's not really an option. Still, it's rare.

Nintendo also warns users of the potential for eyestrain. The manual suggests that players take a 10-to 15-minute break for every hour of play. If you're using the 3-D feature on the 3DS, that frequency doubles to a break every half hour. It also warns that if the player begins to feel dizzy or nauseated, he or she should stop playing for several hours. The company stresses that such symptoms are rare.

There are other potential health problems as well. If you're a gaming junkie, you may be tempted to play all day long. That can lead to injuries as you repeat the same motions throughout the day. Carpal tunnel syndrome is an example of what can happen if you play for long stretches of time frequently.

Nintendo also cautions players who wish to change the 3DS battery. If your battery's life isn't what it used to be, you can swap it out for a new one. But you should be careful with old batteries -- if they're damaged they may leak battery acid.

Finally, the company warns that since the device is capable of broadcasting over WiFi, it should not be used near people who have pacemakers. The concern is that the WiFi will create radio-frequency (RF) interference that could cause the pacemaker to malfunction.

Early reviews of the 3DS unveiled concerns unrelated to health. Despite an early demo of a game that used 3-D as an integral part of gameplay, the company now supports a different approach to game development. People with vision problems in one eye may not perceive 3-D images at all. Nintendo doesn't want to leave these people out of the fun and so the company stresses that games should be playable in either 2-D or 3-D mode. But that means the 3-D feature becomes more of a gimmick than an integrated feature necessary for gameplay.

And not all 3DS games will be in 3-D. Several 3DS titles, including an entry in the popular Street Fighter franchise, don't support 3-D at all. While the 3DS has other new features besides the 3-D capability, it may not pack enough punch for gamers to decide to upgrade to the new system.

Will the 3DS pave the way to a new era of handheld gaming or is it destined to join Nintendo misfires like the Virtual Boy or Power Glove? Time will tell.

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