a technology in which visible spectrum is used to transfer data....

1. PRESENTATION ON LIFI (LIGHT FEDILITY)
PRESENTED BY
D.PUNYA SANDEEP&
CH.SRI RAMA KRISHNA
SACET,CHIRALA

2. CONTENTS
INTRODUCTION
WORKING
COMPARISION
ADVANTAGES
DISADVANTAGES
APPLICATIONS

3. INTRODUCTION
WHAT IS LI-FI??
 LI-FI is transmission of data through illumination ,sending data through a LED
light bulb.
 LI-FI comes under VLC(VISIBLE LIGHT COMMUNICATION)

4. INTRODUCTION
HISTORY

The technology truly began
during the 1990's in countries
like Germany, Korea, and
Japan where they
discovered LED's could be
retrofitted to send
information. Harald Haas
continues to wow the world
with the potential to use light
for communication.

5. WORKING
How LI-FI works?
 operational procedure is very simple, if the led is on, you transmit a digital
1, if its off you transmit a 0. The LEDs can be switched on and off very
quickly, which gives nice opportunities for transmitting data. Hence all that
us required is some LEDS and a controller that code data into those LEDs.

6. Working principle

7. Transmission element
 Signals from the data input is modulated to
intensity of light.
 Transmission side simply contains an led lamp
which transmits the modulated light signals.
 This led lamp contains a series of LED’s which
proto fits according to the input given .

8. Receiving element
 Receiving elements are “AVALANCHE PHOTO DIODE” and image sensor.
 Avalanche photo diode is responsible for converting the light signal into
electrical signal and further the procedure is carried out by image sensor.

9. illustration

11. COMPARISION
WHY VLC??
o Gama rays cant be used as they could be dangerous.
o X-rays have similar health issues.
o Ultraviolet light is good for place without people, but other wise dangerous
for the human body.
o Infrared, due to eye safety regulation, can only be used with low power.

12. DIFFERENCE B/W TECHNOLOGIES
TECHNOLOGY
SPEED
Fire wire
800 Mbps
USB 3.0
5 Gbps
Thunder bolt
20 Gbps
Wi-Fi
150 Mbps
Bluetooth
3 Mbps
IrDA
4 Mbps
Wi-Gig
2 Gbps
Giga-IR
1Gbps
Li-Fi
>10 Gbps

13. APPLICATIONS
 Used in traffic lights which can communicate with cars to avoid accidents.
 Used in airlines: Generally in airlines mobile phones can’t be used as they
can effect the radars which are main way of communication.
 Used in power plants for faster data exchange.
 Underwater communications. (rare)

14. ADVANTAGES
 Availability
 Efficiency
 High security
 Easy to use
 Fast data transfer
 Harmless
 Low-cost

15. DISADVANTAGE
 However, everything comes with a disadvantage. The major disadvantage
here is the fact that these signals cannot penetrate walls. So if you want to
move from one room to another, you will need to have a wired bulb
present in that room as well!

16. CONCLUSION
The possibilities are numerous and can be explored
further. If this technology can be put into practical use,
every bulb can be used something like a Wi-Fi hotspot to
transmit wireless data and we will proceed toward the
cleaner, greener, safer and brighter future.