When the application installed on the Android Mobile is
used to send the data to the USB port, FT230 will realize the
conversion of signal of USB from differential to TTL. Then a
voltage follower connected to the output pin of FT230 pull up
the signal current to an adequate level, driving LED for
lighting. A high power white light LED of 300mW and with
the beam angel 120° is used as the optical transmission source.
OOK NRZ data for Intensity modulation (IM) and direct
detection (DD) scheme is chosen for the widely reception in
VLC research.