Light sensor:
Gesture detection – the detection of human movements – may be used to enable advanced, differentiated smart features in portable electronics such as smart phones. Many of these features save energy by enabling electronics to expend the minimum amount of energy necessary to provide appropriate screen illumination levels. For example, when a phone is held to a user’s ear during normal conversation, the user can not see the screen, and therefore it may be turned off. This saves energy during the conversation. When the phone is moved away from the ear, the screen may re-illuminate to allow the user to access the display information as soon as the phone is brought into lineof-sight. Near-far threshold detection can turn the display off when the phone is held to the ear, or turn the speaker volume up when it is held away. In addition, the gesture of moving a finger toward a screen may cause it to illuminate. This saves energy by allowing the screen to go dark sooner after its last use, and assists the human interface by eliminating the need for a button depress or track-ball click. Finally, gestures across a touch-less screen may be interpreted to cause scrolling or expansion of discrete on-screen images.
Touch Screen:
1) Self-Service Check Outs
Many supermarkets use touch screens to save time for both customers and cashiers. Customers can weigh produce, look up codes, and choose methods of payment from touch screen displays.
2) ATM Machines
Most ATM machines use touch screen technology. It allows users to input their information without having to press buttons, which makes ATM use much easier.
3) PDAs
PDAs are one of the first popular uses of touch screen technology. Today's stand-alone PDAs are used for Internet browsing and media playing, but are declining in usage these days.
4) iPhone
The Apple iPhone uses its touch screen display to provide users with an easy way to navigate. Users can dial, text, listen to music