This presentation discusses Li-Fi, which is a technology that transmits data through illumination by using LED light bulbs. It began development in the 1990s and works by transmitting either a 1 or 0 by turning the LED on or off very quickly. Li-Fi provides transmission speeds greater than 10 Gbps, faster than technologies like Wi-Fi, Bluetooth, and infrared. Potential applications include using car headlights and streetlights for communication to prevent accidents, providing free internet access points everywhere, and enabling undersea communication without interference. Challenges include the need for line of sight and light not penetrating walls, but these can be addressed. If implemented widely, Li-Fi could create a cleaner, greener and safer future with

1. PRESENTED BY:-
B.BALA SUDHARSANA KRISHNAN (CSE)
S.SURESH KUMAR(CSE)
Presentation on lifi (light fedility)

2. 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)

3. 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.

4. 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.

5. WORKING PRINCIPLE:-

6. 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

7. 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.

8. ILLUSTRATION:-

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

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

12. APPLICATION:-
ACCIDENT PREVENTION :
o In streets, for traffic control. Cars have LED based headlights,
LED based backlights, and Car can communicate each other
and prevent accidents in the way that they exchange
Information. Traffic light can communicate to the car and so on.

13. FREE ACCESS POINTS :
 By implementing the Technology worldwide every street
lamp would be a free access point.

14. UNDERSEA :
 If their wires were cut and replaced with light — say from a
submerged, high-powered lamp — then they would be much
 freer to explore. They could also use their headlamps to
communicate with each other.
 It can be used underwater without radio interference because
salt conducts electricity.

15. CHALLENGES OF LIFI :
 Li-Fi requires line of sight.
 Visible light can’t penetrate through brick walls as radio waves.
 A side effect of Li-Fi is that your power cord immediately
becomes your data stream, so if you have power, you have
internet.

16. OVERCOMING THE CHALLENGES OF LI-FI :
 In LED bulb, the capacitor can be used to store the heat energy
and it can be converted into electrical energy .This can enable
the person to use the internet for somemore time and makes the
important data to be save. As like radiowaves, the visible light
can’t penetrate through the walls. This is one of the advantage
of LI-FI that it can secure data in the defence field.

17. 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.