∞ What iPhone 4's gyroscope means for iOS gaming

Steve Jobs gave a quick demo on Monday of iPhone 4 to show off its new gyroscopic capabilities. These new functions will keep iPhone 4 competitive with new handheld gaming systems, along with – presumably – other iOS-enabled devices that Apple produces in the future.

From its inception, the iPhone and all related devices that have followed sport an accelerometer – a device that measures acceleration, enabling the iPhone, iPod touch or iPad to know which direction it’s being held in. It’s the accelerometer that enables the iPhone to automatically adjust from landscape to portrait mode. For gaming applications, the accelerometer has been used to enable players to shake the iPhone or tilt it like a steering wheel to make stuff happen on screen.

iPhone 4 adds a gyroscope – a device that measures orientation, rather than just velocity. Gyroscopes are commonly used in aircraft to measure pitch, roll and yaw, and the iPhone’s gyro is no different in this regard.

All this may sound pretty esoteric; it’s the realm of aeronautics and spaceflight, after all. I don’t think that we’re going to be seeing astronauts and pilots depending on their iPhones to pilot their vehicles any time soon, for example. But a gyroscope has some great application for games.

When the output of the iPhone’s gyroscope is paired with the output from the accelerometer, iPhone developers will now be able to create applications that can sense motion on six axes – up/down, left/right, forward/backward, combined with rotation around three perpendicular axes – pitch, yaw, and roll.

This will put iPhone 4 well ahead of the capabilities of other smartphones when it comes to playing games, as well as the Nintendo DS and the Sony PSP (Nintendo’s forthcoming 3D handheld system purportedly has similar features, though Nintendo has not, as of yet, formally introduced the device).

This puts the iPhone more into the realm of Nintendo’s Wii home console, which sports similar capabilities when its remotes are paired with a Nintendo-made accessory called the MotionPlus. Sony’s PlayStation 3 controllers also sport gyroscopic functionality.

Apple is exposing iPhone 4’s new functionality with new Application Programming Interfaces (APIs) it’s calling CoreMotion; iOS developers will need to tap into these calls to support gyroscopic functionality in their games.

Jobs briefly showed a tech demonstration of one possible game – a brick-stacking game akin to the tabletop game “Jenga,” in which he tilted and rotated a virtual tower of wooden-looking blocks before knocking them over. It was a simple but effective show of what CoreMotion can do on the iPhone 4 – and already game developers are buzzing about what else they can use the technology for.

One postscript worth mentioning – Apple’s timing for WWDC couldn’t be better. It comes just two weeks before the video game industry’s biggest event of the year, the Electronic Entertainment Expo (E3) in Los Angeles, Calif. Microsoft and Sony are both expected to show how the 3D gaming technology that they’re working on is progressing. Microsoft and Sony both debuted hardware at last year’s event – Microsoft’s “Project Natal,” and Sony’s new Wii-like wand controller.

But while Microsoft and Sony debuted the tech last year and have yet to ship it, Apple has gathered developers in San Francisco this week to learn more about CoreMotion, and are shipping a product that can actually put it to use before the end of the month.



  • I'd sure like to know what how this gyroscope works. Seems like it would be pretty hard to have some spinning mini weight involved.

    • I'm pretty sure there are no spinning parts. The datasheet for the gyro (http://invensense.com/mems/gyro/tripleaxis.html) says "The ITG-3200 consists of three independent vibratory MEMS gyroscopes, which detect rotational rate about the X (roll), Y (pitch), and Z (yaw) axes. When the gyros are rotated about any of the sense axes, the Coriolis Effect causes a deflection that is detected by a capacitive pickoff."

  • veggiedude

    Imagine a DOOM type game incorporating the GYRO. You are taking fire from behind. Just physically turn around 180 degrees to kill the enemy and then turn back to front to resume killing the mob. Currently, to do that same thing is more cumbersome to actually rotate the phone to the direction you want, and then to rotate it back to the right position, saving 2-3 seconds makes all the difference in a game like that.

    • Of course, it also means that some games will have you gesticulating wildly like you're having some sort of spastic fit, but hey, if that's what it takes to get you into the game… 😉

  • AndrewMc

    Think of it, a racing game where you can look out the car windows to the left and right by just moving your iPhone! How cool!!

  • This thing's gonna be awesome when paired with an AppleTV that runs apps!

  • Can't wait to see people on crowded commuter trains attempting to play one of these newer gyro-controlled games! 😉

    I imagine there'll be sensitivity controls to allow players to minimize their movements.

  • Wow something more to make a iPhone playing geeks look like a weirdos on commuter trains/buses.

  • The Gyroscope in the iPhone 4 is 3-axis and is similar in feature to the digital compass and the accelerometer together in the iPhone 3GS. The difference is that it is only relative rotation detection (the gyroscope that is). Actually this is better explained in the iPhone 4 secrets webpage.

    http://www.edepot.com/iphone.html

    You have to scroll down a bit after the Hardware section. As you can see, it is not really needed unless you are moving.

  • Franko

    I love the gyro, http://www.youtube.com/watch?v=1kQ5M3PLn60 but these air drums and shooting range is all I have found.