Catching up on my reading since I've been gone, ran across this today. Pretty interesting stuff, especially at the end of the article, regarding airplane travel.
http://www.economist.com/node/21543470
AMONG the many new gadgets unveiled at the recent Consumer Electronics Show in Las Vegas was a pair of smartphones able to exchange data using light. These phones, as yet only prototypes from Casio, a Japanese firm, transmit digital signals by varying the intensity of the light given off from their screens. The flickering is so slight that it is imperceptible to the human eye, but the camera on another phone can detect it at a distance of up to ten metres. In an age of Wi-Fi and Bluetooth, flashing lights might seem like going back to sending messages with an Aldis lamp. In fact, they are the beginning of a fast and cheap wireless-communication system that some have labelled Li-Fi.
The data being exchanged by Casio’s phones were trifles: message balloons to be added to pictures on social-networking sites. But the firm sees bigger applications, such as pointing a smartphone at an illuminated shop sign to read information being transmitted by the light: opening times, for example, or the latest bargains.
http://www.economist.com/node/21543470