Cell-phone manufacturers are seeking new functionality to differentiate their mobile handsets and bring about a host of newer and richer user experiences. Motion processing is emerging as the only technology that can deliver such promise.

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Motion processing technology can bring about a next-generation gesture-based user interface (UI) for menu navigation. It also can enable mobile authentication, enhance location-based services, deliver an immersive gaming experience, and improve camera image stabilization (IS).

But delivering this credibly isn’t possible in existing solutions based purely on three-axis accelerometer sensors or even by adding a compass. However, a six-axis motion processing solution using microelectromechanical-systems (MEMS) technology can be used to enable emerging motion-based applications in the new generation of smart phones.

Mobile Phones Sense Motion Today

Apple’s introduction of the iPhone demonstrating tilt control enabled by MEMS accelerometers in 2007 raised the bar for motion-based applications in mobile devices across all platforms. According to iSuppli, 27% of the cell phones produced in 2009 feature a MEMS accelerometer, due to their inclusion in the iPhone and other popular smart phones.¹

The accelerometer detects motion when the phone is turned from portrait to landscape and changes the display accordingly. The three-axis MEMS accelerometer is also used to control some rudimentary games, perform power management, shuffle music, “undo” actions, and enable pedometers and other context-aware apps.

Figure 1. A three-axis gyroscope can detect roll, pitch, and yaw rotations.

While accelerometers provide basic motion sensing for simple orientation and tilt applications, they have limitations affecting their operation and performance in more complex applications, such as handwriting recognition or image stabilization where up to 20 Hz of hand jitters must be detected.

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