Visible Light Communication Based On Android Telephone Camera

Visible light communication is considered as a promising future wireless communications technology. Progress in light emitting diode (LED) technology has driven researchers to go one step further from illumination and use this technology for indoor wireless data transmission.This article scheme for data reception in a mobile phone using visible light communication(VLC) is proposed. The camera of the smartphone is used as a receiver in order to capture the continuous changes in state(on-off) of the light, which are invisible to the human. The information is captured in the camera in the form of light and dark bands which are then decoded by the smartphone and received message is displayed. By exploiting the rolling shutter effect of CMOS sensors, a data rate much higher than the camera frame rate is achieved. Firstly, this thesis gives an overview of VLC technology and smartphone research background, and introduces the composition of the smartphone and theirs working principle.Secondly, analysis the white LEDs working principle and characteristics and investigates the white LEDs lighting source transmission channel model, as well as the function of the various components. The transmitting terminal hardware circuit includes the white LEDs drive circuit, signal modulation circuit, and filter circuit etc. The software comprises the realization of the ook technology and Android APK. Finally, through this system,the experiment about transmission is accomplished. The test result of the system shows that the channel parameters such as speed, encoding, sensor can influence the performance of the VLC system, through the analysis of these results.From the perspective of VLC application, this paper provides the specific theoretical basis and rich result of research.