Ever turned an iPhone to the side, only to see the screen adjust from portrait to landscape view? Seen the ad for that smart phone where they shake the handset to roll a pair of virtual dice?
Welcome to the world of motion sensing and accelerometers. These are MicroElectroMechanicalSystems. They have the capability to detect and measure motion. They consist of electronic systems combined with very small sized mechanical systems. Microelectronic integrated circuits can be thought of as the "brains" of a system and the micro mechanical system augments this decision-making capability with "eyes" and "arms", to allow microsystems to sense and control the environment.
Beyond game play and screen orientation, the most popular uses for MEMS accelerometer motion sensors in phones include power management and shake modes for control of tracks in music phones, context awareness and pedometers.
The market for microelectromechanical sensors for mobile phones is estimated to grow more than triple from 2008 to 2013, which means more phones will get these features. Lets be on the look out for them. :)