Communication with Ambient Light using Digital Micromirror Devices

Passive visible light communication (VLC) takes advantage of the pervasivenature of ambient light in our environment for wireless transmissions. Thedesign of transmitters in passive VLC predominantly uses Liquid Crystal Displays (LCD’s). While LCD’s are an economical choice with low power consumption, they lack some key properties that are desirable for passive VLC.For example, LCD’s absorb more than half of the incident light, leaving onlya small portion to be used for communication. In addition, since the directionof ambient light can change over time, the relative positions of the LCD’s andreceivers have to be adjusted constantly to maintain the correct alignment. Toovercome these shortcomings, this thesis proposes the use of a novel transmitterwith integrated optical fibres and digital micro-mirror devices (DMD’s). DMD’sare able to reflect up to 97% of the incident light, while the accompanying optical fibres aim to capture ambient light from various angles and guide them tothe DMD’s in a fixed direction. This design is a first step towards the goal ofdecoupling the direction of ambient light from the direction of the optical link,while achieving the same communication characteristics as LCD’s with a muchsmaller device. Furthermore. this thesis describes an app to allow users to easilyinteract with the system. An evaluation shows that the link can achieve a datarate up to 1bps at a distance of 60cm.Electrical Engineering | Embedded System