A portable multimedia information device in a wireless optical data link

This paper describes implementation of a information device that receives information from a free space optical data link established using visible light LEDs. The visible light, which is transmitted from a transmitter made up of LEDs, is modulated and encoded with data and information. The portable receiver is consisted of a demodulation circuit and an interface to a handheld PC. Software applications have also been developed on this hardware platform so that the mobile PC device can receive data, audio and graphics through the visible light from the transmitter, which is located at some distance from the device. With the high frequency switching of the LEDs, the transmitter appears to be constantly illuminated.