FIGURE Google Search activates voice search using the proximity sensor. MOTION SENSOR NOTE iPhone 4 has a three-axis gyroscope. Paired with the accelerometer, it makes the iPhone capable of advanced motion sensing, such as user acceleration, angular velocity, and rotation rate. One of the most widely used sensors is the accelerometer, also known as a “motion” sensor. The accelerometer can detect the iPhone’s orientation and adjust the display accordingly. Perhaps the most practical accelerometer feature is the ability to change the display from portrait to landscape when the iPhone is rotated. Other accelerometer-based features can be found in games, musical instruments, contact. | FIGURE Google Search activates voice search using the proximity sensor. MOTION SENSOR NOTE iPhone 4 has a three-axis gyroscope. Paired with the accelerometer it makes the iPhone capable of advanced motion sensing such as user acceleration angular velocity and rotation rate. One of the most widely used sensors is the accelerometer also known as a motion sensor. The accelerometer can detect the iPhone s orientation and adjust the display accordingly. Perhaps the most practical accelerometer feature is the ability to change the display from portrait to landscape when the iPhone is rotated. Other accelerometer-based features can be found in games musical instruments contact management tools photography tools e-readers and pedometers see FIGURES for a few examples . FIGURE Marble Maze uses the motion sensor to move the silver ball through the maze. FIGURE Bump uses the accelerometer to detect when the user shakes the device as a way to exchange contact information. FIGURE ProCamera uses the motion sensor to improve image capture. 28 CHAPTER 2 IPHONE DEVICE OVERVIEW Download from Location and Compass Information The iPhone provides location and compass information at the time of this writing the compass is available only on the iPhone 3GS and later . Combined the two features can offer powerful navigation systems. LOCATION INFORMATION The iPhone communicates with Earth-orbiting satellites to determine its location. If the phone cannot access any satellites for example inside buildings it uses available WiFi spots or cell towers to help triangulate the iPhone s position. With this location information users can pinpoint themselves on a map and look up directions to a point of interest FIGURE . Although this information is most commonly used for navigation many social applications such as Gowalla and Foursquare FIGURES respectively also take advantage of this feature. FIGURE TomTom FIGURE Gowalla .
