The document discusses Li-Fi (Light Fidelity) technology, which uses visible light communication to transmit data wirelessly. It describes how Li-Fi works by encoding digital data using the rapid flickering of LED lights that is undetectable to the human eye. The document outlines some key advantages of Li-Fi such as its large usable bandwidth, efficiency, availability anywhere there is light, and increased security compared to Wi-Fi. Several applications are proposed including underwater communications, use in healthcare settings, providing internet access from street lights, and real-time traffic updates. Potential future applications and some disadvantages of Li-Fi are also mentioned.

1. LI-FI (LIGHT FIDELITY)
Presentation By:
Mr. S.Senthil Ilangovan
AP/EEE

2. CONTENTS
 What is Li-Fi?
 Concept of Li-Fi
 Demonstration of Li-Fi
 Why is it required? Present Scenario.
 Visible Spectrum. Why?
 LiFi over WiFi
 Working
 Applications
 Ideas for more applications of this technology
 Disadvantages

3. • Li-Fi, as coined by Prof. Harald Haas during his TED Global
talk
• It is a bidirectional, high speed and fully networked wireless
communications similar to Wi-Fi.
• Li-Fi is a subset of optical wireless communication (OWC)
and can be a complement to RF communication (Wi Fi or
Cellular network), or a replacement in contexts of data
broadcasting.
WHAT IS LI-FI?

4. • Li-Fi, is a transmission of data through illumination.
• Sending data through the LED bulb that varies in intensity
faster than the human eye can follow.
• Switching on and LED is a logical ‘1’, switching it off is a
logical ‘0’.
• It is possible to encode data in the light by varying the rate at
which LED’s flicker on and off to give different strings of 1s
and 0s.
• Modulation is so fast that human eye doesn’t notice.
Concept of LI-FI

5. • On 12th July 2011, Harald Hass used a table lamp with an
LED bulb to transmit a video of blooming flowers that was
then projected onto a screen behind him.
• During the event he periodically blocked the light from lamp
to prove that the lamp was indeed the source of incoming
data.
• At TED Global, Haas demonstrated a data rate of
transmission of around 10Mbps (comparably good UK
transmission)
Demonstration of LI-FI.

6. • Two months later he achieved 123Mbps.
• Back in 2011 German scientists succeeded in creating an
800Mbps (Megabits per second) capable wireless network by
using nothing more than normal red, blue, green and yellow.
Demonstration of LI-FI. (cont.)

7. Existing wireless technology –
Why do we need an alternate
technology?
• CAPACITY
• EFFICIENCY
• AVAILABILITY
• SECURITY

8. Present Scenario
• Radio Spectrum is congested but the demand for
wireless data double each year.
• Every thing, it seems want to use wireless data but the
capacity is drying up.

9. VISIBLE SPECTRUM

10. Why Visible Light?
• 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. LIFI OVER WIFI

12. WORKING

13. Applications:
• Underwater communications
• Health sector
• Internet anywhere
• Safety and management

14. Underwater communications:
• Radio waves cannot be used under water.
• Because these waves are strongly absorbed by sea water
within feet of their transmission
• But LIFI is suitable for underwater communication
because light rays can pass through the water

15. Health Sector:
• WIFI is not safe to be used in hospitals and other various
health care sectors (Cancer patients, Neuro-patients)because
it penetrates human body.
• Continuous monitoring of patients health without wired
equipment's.
• LIFI can be implemented and well suit in this sector.

16. Internet Anywhere:
• Street lamps, light of vehicles can be used to access internet
anywhere in footpaths, roads, malls, anywhere where light
source is available.

17. Safety Management:
• It can be used to update traffic information at almost every
instant and it will be easy for traffic police to deal with
traffic and catch the one who breaks the rule.

18. Finding the location of a person :
• LiFi uses visible light and this property can be exploited in
finding the location of people.
• Suppose if a child is misplaced and he/she is wearing an
earing which is made of Led’s.
• This led can constantly communicate with the visible light
available and reveal the location of the child.
IDEAS FOR MORE APPLICATIONS :

19. Navigation System :
• Since visible light is present everywhere, we can create
internal navigation systems for the bigger areas to create
automated machinery/ automatic navigation for the
visitors.
IDEAS FOR MORE APPLICATIONS :

20. Under water management:
• The LEDs can be embedded in the water bed to reveal the
various impurities underwater.
• The various LED’s will communicate with each other to
give the overall amount of impurity in that particular area.
IDEAS FOR MORE APPLICATIONS :

21. Instant data transfer between the devices :
• The high speed transfer of the LED’s can be used to
transfer the data between the devices.
IDEAS FOR MORE APPLICATIONS :

22. DISADVANTAGES
Nothing in this world is perfect and so does LIFI.
• These signals cannot penetrate walls.
• So the person needs wired bulb in that room also.
• Only works if there is direct line of sight between
source and receiver.
• Used for broadcast and it is difficult to uplink.

23. 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 hotspots to
transmit wireless data.

24. REFERENCES
• http://www.ijstr.org/final-print/oct2014/Li-fi-A-New-Era-
Of-Wireless-Communication-Data-Sharing.pdf
• https://www.youtube.com/watch?v=NaoSp4NpkGg

25. ??????????
(Queries)

26. Thank You!