Passive visible light communication (VLC) takes advantage of the pervasive
nature of ambient light in our environment for wireless transmissions. The
design of transmitters in passive VLC predominantly uses Liquid Crystal Displays (LCD’s). While LCD’s are an economical ch
...
Passive visible light communication (VLC) takes advantage of the pervasive
nature of ambient light in our environment for wireless transmissions. The
design 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 only
a small portion to be used for communication. In addition, since the direction
of ambient light can change over time, the relative positions of the LCD’s and
receivers have to be adjusted constantly to maintain the correct alignment. To
overcome these shortcomings, this thesis proposes the use of a novel transmitter
with integrated optical fibres and digital micro-mirror devices (DMD’s). DMD’s
are 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 to
the DMD’s in a fixed direction. This design is a first step towards the goal of
decoupling the direction of ambient light from the direction of the optical link,
while achieving the same communication characteristics as LCD’s with a much
smaller device. Furthermore. this thesis describes an app to allow users to easily
interact with the system. An evaluation shows that the link can achieve a data
rate up to 1bps at a distance of 60cm.