I would like to demonstrate for the first time in public that it is possible to transmit a video from a standard off-the-shelf LED lamp to a solar cell with a laptop acting as a receiver. There is no Wi-Fi involved, it's just light. And you may wonder, what's the point? And the point is this: There will be a massive extension of the Internet to close the digital divide, and also to allow for what we call "The Internet of Things" -- tens of billions of devices connected to the Internet. In my view, such an extension of the Internet can only work if it's almost energy-neutral. This means we need to use existing infrastructure as much as possible. And this is where the solar cell and the LED come in. I demonstrated for the first time, at TED in 2011, Li-Fi, or Light Fidelity. Li-Fi uses off-the-shelf LEDs to transmit data incredibly fast, and also in a safe and secure manner. Data is transported by the light, encoded in subtle changes of the brightness. If we look around, we have many LEDs around us, so there's a rich infrastructure of Li-Fi transmitters around us. But so far, we have been using special devices -- small photo detectors, to receive the information encoded in the data. I wanted to find a way to also use existing infrastructure to receive data from our Li-Fi lights. And this is why I have been looking into solar cells and solar panels. A solar cell absorbs light and converts it into electrical energy. This is why we can use a solar cell to charge our mobile phone. But now we need to remember that the data is encoded in subtle changes of the brightness of the LED, so if the incoming light fluctuates, so does the energy harvested from the solar cell. This means we have a principal mechanism in place to receive information from the light and by the solar cell, because the fluctuations of the energy harvested correspond to the data transmitted. Of course the question is: can we receive very fast and subtle changes of the brightness, such as the ones transmitted by our LED lights? And the answer to that is yes, we can. We have shown in the lab that we can receive up to 50 megabytes per second from a standard, off-the-shelf solar cell. And this is faster than most broadband connections these days. Now let me show you in practice. In this box is a standard, off-the-shelf LED lamp. This is a standard, off-the-shelf solar cell; it is connected to the laptop. And also we have an instrument here to visualize the energy we harvest from the solar cell. And this instrument shows something at the moment. This is because the solar cell already harvests light from the ambient light. Now what I would like to do first is switch on the light, and I'll simply, only switch on the light, for a moment, and what you'll notice is that the instrument jumps to the right. So the solar cell, for a moment, is harvesting energy from this artificial light source. If I turn it off, we see it drops. I turn it on ... So we harvest energy with the solar cell. But next I would like to activate the streaming of the video. And I've done this by pressing this button. So now this LED lamp here is streaming a video by changing the brightness of the LED in a very subtle way, and in a way that you can't recognize with your eye, because the changes are too fast to recognize. But in order to prove the point, I can block the light of the solar cell. So first you notice the energy harvesting drops and the video stops as well. If I remove the blockage, the video will restart. (Applause) And I can repeat that. So we stop the transmission of the video and energy harvesting stops as well. So that is to show that the solar cell acts as a receiver. But now imagine that this LED lamp is a street light, and there's fog. And so I want to simulate fog, and that's why I brought a handkerchief with me. (Laughter) And let me put the handkerchief over the solar cell. First you notice the energy harvested drops, as expected, but now the video still continues. This means, despite the blockage, there's sufficient light coming through the handkerchief to the solar cell, so that the solar cell is able to decode and stream that information, in this case, a high-definition video. What's really important here is that a solar cell has become a receiver for high-speed wireless signals encoded in light, while it maintains its primary function as an energy-harvesting device. That's why it is possible to use existing solar cells on the roof of a hut to act as a broadband receiver from a laser station on a close by hill, or indeed, lamp post. And It really doesn't matter where the beam hits the solar cell. And the same is true for translucent solar cells integrated into windows, solar cells integrated into street furniture, or indeed, solar cells integrated into these billions of devices that will form the Internet of Things. Because simply, we don't want to charge these devices regularly, or worse, replace the batteries every few months. As I said to you, this is the first time I've shown this in public. It's very much a lab demonstration, a prototype. But my team and I are confident that we can take this to market within the next two to three years. And we hope we will be able to contribute to closing the digital divide, and also contribute to connecting all these billions of devices to the Internet. And all of this without causing a massive explosion of energy consumption -- because of the solar cells, quite the opposite. Thank you.

Hey friends, welcome to the YouTube channel ALL ABOUT ELECTRONICS. So, in this video, we will learn about the Li-Fi technology. Which is the abbreviation of term Light Fidelity. So, in simple terms, we can say that this Li-Fi technology is nothing but light based wi-fi technology. And as we know, this Wi-Fi is fully networked, bi-directional wireless communication technology. Where data is being transmitted using the radio waves. While in the case of Li-Fi technology, the data is transmitted in the form of visible light using the LED light source. So, this house hold LED bulbs and LED lamps which are used as a light source can also be used to transmit the data. So, first of all, let's understand how this Li-Fi technology works. So, if you see any LED light source, if you provide the constant current to this LED bulb, it provides the constant illumination or constant brightness. So, as we change the current that is flowing through the LED bulb, the illumination or brightness of this bulb will change. So, this princi[ple is used for transmitting the data wirelessly using this Li-Fi technology. So, if no current or minimum current is flowing through this LED bulb then, the brightness of this LED source will be minimum. And that will be treated as digital 0. So, digital 0 will be transmitted at the receiver side. Similarly, when the light bulb is ON, or we can say that if the maximum amount of current is flowing through this LED bulb then the illumination or brightness of the LED bulb will be maximum. And that will be treated as digital 1. So, whenever the LED is ON, so digital 1 will be transmitted at the receiver side. So, in this way, by flickering the LED light source very rapidly we can transmit the data in the form of 1's and 0's to the receiver. And if this flickering is happening at million times per second then we can not see this flickering by our naked eyes. And we can treat this LED bulb source as normal regular bulb source. So, now let's see the schematic of Li-Fi transmitter and receiver system. So, as you can see, the data which is coming from the web server or the internet first it will go to the MODEM, which provides the necessary modulation to the incoming data stream. Then this modulated data is fed to the LED driver, which changes the driving current for this LED bulb according to the incoming streaming data. At the receiver end, if you see, the optically received data is first converted into the electrical signal using the photo receiver or photo diode. And after the signal conditioning, this data is being fed to the computer or laptop. So, to receive this incoming data, at the receiver side we require the Li-Fi dongle, which consists of photo receiver as well as IR transmitter. Now this infrared transmitter can be used to transmit the uplink data back to the LED source. Now, one such company which provides the complete Li-Fi solution is Pure LiFi. Which generally makes these Li-Fi dongles. So, now as we know, how this Li-Fi technology works, now let's see the advantages of this Li-Fi technology over the other wireless communication technologies. So, these are the some of the advantages of the Li-Fi technology over the other wireless communication technologies. So, first let's talk about the speed. So, so far the researchers have achieved the speed up to the 10 Gbps in the lab scale prototype models. And this speed can further be enhanced by using the array of LED source or by using the multiple colours of LEDs like RGB LEDs, where each LED source is able to transmit the data up to the 10 Gbps. So, using such technologies, the researchers have achieved the maximum speed up to the 100 Gbps. So, now let's compare its speed with other wireless communication technologies. So, if we compare it with 4G/LTE or particularly the LET advanced, the maximum achievable speed under this LTE advanced is 1 Gbps for the stationary user and 100 Mbps for the mobile user. But all these speeds are the theoretically achievable maximum speed. But actual speed may be much lesser compared to this theoretically achievable maximum speed. So, if you see the countries which provide the fastest internet in the world, the average 4G/LTE speed in such countries is in the range of 40-50 Mbps, which is much lesser compared to the speed which is provided by the Li-Fi. So, now let's compare the speed of Li-Fi with Wi-Fi. Now, in case of Wi-Fi, if you see the standard IEEE 802.11.ac, the maximum speed which can be supported by this standard is 1.3 Gbps. And that is in the 5 GHz band, which is almost 100 times lesser compared to the speed which is supported by the Li-Fi. And if you see the another Wi-Fi standard, which is not commercially available yet, that is IEEE 802.11.ad, the maximum speed which can be supported by this standard is 7 Gbps. And all the speeds which are mentioned over here are the theoretically achievable maximum speeds. But the actual speeds may be quite lesser compared to the theoretically achievable maximum speeds. And still, if we consider the maximum speed which is supported by this Wi-Fi technology, the Li-Fi technology is still 10 times faster compared to this Wi-Fi technology. Well, right now the speed which is provided by the Wi-Fi technology is sufficient for our day to day life. But as we are moving in the era of Internet of Things, where each device is able to communicate with each other, soon you will find that the speed which is provided by the Wi-Fi technology is insufficient. And you will require the insane speed like 100 Gbps, which as of now looks like a dream. So, next, if you see the electromagnetic spectrum, the bandwidth of the radio wave is up to 300 GHz. But if you see the bandwidth of this visible spectrum alone, the bandwidth of this visible spectrum is around 300 THz. Which is almost 1000 times more compared to the bandwidth of the radio waves. So, not only you can achieve the higher speed but also you will not find any kind of electromagnetic radio interference. So, now in the case of Li-Fi, as we are using the visible light source, the visible light source can not cross the walls, unlike the case of Wi-Fi, where the radio waves are able to transmit across the walls. So, in this way, this Li-Fi technology provides the one more layer of security. So, these are the advantages of this Li-Fi technology over the other wireless communication technologies. So, now let's see the different applications of this Li-Fi technology. So, this Li-Fi technology can be used in the hospitals. As this Li-Fi technology is providing very high-speed internet communication, so the real time health monitoring of the patient will be possible. So, apart from that this Li-Fi technology can be used for the under water communication. Also, using this technology, the vehicles can communicate with each other using the front and the rear lights. And using this technology, we can prevent the accidents. Also, this Li-Fi technology can be used in the aeroplanes to provide the internet to the passengers. And not only that if this technology is fitted into our street lights, then even our street lights can provide us high-speed internet. So, these are the some of the applications in which this Li-Fi technology can be used. But still, if you see, this Li-Fi technology is the futuristic technology. That means, the commercially there are no products which are available which provides the insane speed up to the 10 Gbps or 100 Gbps. So, in the upcoming years, we might see the technlgies or devices which support this Li-Fi technology. So, right now, as we are seeing the Free Wi-fi Zone in the cafeteria, in future we might see Free Li-Fi zone in the cafeteria. So, now bigger question is if Li-Fi is the future of internet then what about the already existing wireless technologies. So, the answer is that in future also all the existing technologies will remain. And rather this Li-Fi technology will complement all the existing technologies. Because this Li-Fi is short range communication. So, using this technology we can not cover the entire area using the light. So, grossly we can say, when you require large coverage, we will still prefer Wi-Fi and 4G/LTE but in short coverage, like in the case of our room or hotel or even offices, we can still prefer this Li-Fi technology. So, I hope in this video, you understood about this Li-Fi technology.

imagine a world where light becomes data Wi-Fi is simple but powerful we all know how a lightbulb works when an electrical current is applied to an LED light bulb a constant stream of light is emitted from the bulb which we see as illumination since LED bulbs are electronic devices the current and therefore the light can be modulated at extremely high speeds this can be detected by a photo detector and converted back to electrical current therefore carrying data this is the nervous system of an internet revolution Wi-Fi doesn't replace your internet service provider you'll still need them to get the Internet to your home or office via wires however once you have that high-speed connection you can deploy your fast secure Wi-Fi network using power over ethernet or power line communications Wi-Fi offers greater density than many other radiofrequency solutions for example if you have an average Wi-Fi router in your office that provides up to 100 megabits per second and 15 people are connected to that router it means that you might only be able to access or megabits per second however with a live by network of lights that offer 42 megabits per life even if you had only eight lights in your room those same 15 people could share more than 300 megabits per second that's dense and fast wireless communication real life I is also bi-directional full duplex and high-speed data is transmitted and received at the same time resulting in a really fast reliable user experience especially when doing things like Skype calls video streaming and virtual reality real life I is fully networked that means all the lights in your life I network can speak to each other and handover as you move around the space each light even has its own IP address which means that you can offer location tracking and geofencing within your network Wi-Fi a world with unprecedented data and bandwidth be part of the light revolution

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velma eye is reimagining the role light plays in the universe [Music] a new wireless communication technology that uses lightweights from leds for data transmission potentially offering 10 times the speed than traditional wi-fi [Music] li-fi uses light spectrum to enable high-speed and secured wireless communication data input from the router is transferred to the li-fi access point the same data is encoded and communicated in form of ones and zeros to the li-fi dongle using light spectrum this data is then decoded by li-fi dongle for user access simultaneously performing necessary encoding for uplink communication [Music] spectrum providing 1 000 times more unlicensed spectrum than traditional wireless communication security light cannot transfers through the physical environment enabling secure data passage speed offering high speed internet and data transfer which is 10 times faster than the traditional wi-fi speed safety the technology is environment friendly and has immunity against electromagnetic interference [Music] velma eye and bonnet electronics limited are aiming to drive li-fi adoption in indian defense sector li-fi is poised to replace wide land infrastructure for defense officers enabling backhaul connectivity to temporary defense units surveillance security and building to building connectivity establishing communication with underwater drones creating wireless chain enabling data connectivity for longer distances and submarine communication enabling point-to-point wireless communication system in defense equipments and vehicles li-fi imagined and engineered in india

hello everyone you are welcome to our channel marv tech so today we are going to gain knowledge about the lifi technology before starting the video i would like to say that please subscribe if you had until now and if you enjoy the video then please ensure to hit that like button it gives us motivation to make great content for you people so let's start the video so let's first learn that what is lifi the full form of lifi as light fidelity a lifi network uses the light from led lamps to send data to a device such as a laptop or tablet li-fi uses light beam that is called li-fi visible light communication for data transmission now you would think that why can we see the data transmission actually the beam or rays of light containing data can't be seen by human eyes now let's see that how li-fi technology works li-fi is designed to use led light bulbs similar to those currently in use in many energy conscious homes and offices however li-fi bulbs are outfitted with a chip that modulates the light imperceptibly for optical data transmission li-fi data is transmitted by the led bulbs and received by photoreceptors that simply means a light bulb with li-fi technology inside you would be thinking that what is the difference between li-fi and wi-fi well nice question so let's see the differences between these both the main difference between wi-fi and li-fi is wi-fi uses radio waves in order to transmit data at a slower data rate whereas li-fi uses visible light in order to transmit data at a much faster rate lifi is a groundbreaking technology which has been introduced recently in wireless communication through this technology the bulbs at homes offices and streets will not only be able to light and illuminate the environment but will also be able to transmit data wirelessly at high speed now let's discuss some pros and cons of li-fi first the pros of li-fi li-fi comes with a lot of other benefits here are its major advantages first speed light waves are able to carry far more information than radio waves used in wi-fi technology since the visible light spectrum is almost 10 000 times larger than the spectrum occupied by radio waves this is why data transmission using li-fi is 100 times faster than data transmission using wi-fi li-fi connection can transmit data at the rate of 224 gigabytes per second at this speed a high-definition video can be downloaded in seconds second efficiency li-fi holds the potential to be more energy efficient and cheaper due to the nature of led bulbs which are already efficient on their own lifi technology gives them another purpose this will save costs in homes and workplaces because it could do without electronic devices such as routers modems signal repeaters wave amplifiers and antennas these devices have to be connected to power 24 7 in order for them to function the fact that a lot of infrastructures probably has led lights already in place using li-fi would not be an extra cost on top of that the company pure lifi is also developing solar cells as photo detectors to enable wireless battery charging and wireless internet simultaneously third security radio waves can be intercepted by people outside your network since they can pass through walls compromising the security of your data but light is stopped by opaque objects making lifi significantly more secure than other wireless technologies you won't have to worry about leaking your connection to public spaces potentially giving other people access to your network some rooms could even be designated as high security areas with their own li-fi networks isolating them from other areas of the building where vulnerable iot devices might be connected now let's discuss the cons of li-fi first internet cannot be used without a light source this could limit the locations and situations in which li-fi could be used second because it uses visible light and light cannot penetrate walls the signal's range is limited by physical barriers third other sources of light may interfere with the signal one of the biggest potential drawbacks is the interception of signals outdoors sunlight will interfere the signals resulting in interrupted internet fourth a whole new infrastructure for lifi would need to be constructed okay so guys that's all for today thank you for watching please like the video if you enjoyed it share it with your friends if you find it useful and please don't forget to hit that red subscribe button all these things are free to use and all our social media handles are given below in the description box goodbye and see you in the next video

in the beginning there was fire then the lanterns it was used to communicate with ships at the end of the 19th century edison then revolutionized everything by creating the incandescent light bulb eureka a few years later driven by progress and an increased need for healthy and efficient connectivity a technological revolution appeared all right the li-fi li-fi or light fidelity is a means of communication through life leds have the ability to turn on and off several million times per second by using the invisible spectrum of light the infrared oled.com converts this information into binary data such as optical morse code this modulation occurs so quickly more than 10 million times per second that the eye cannot perceive it with a transmitter and a receiver li-fi transfers data at a very high speed this new communication network is radio wave free very fast super robust and ultra secure it's like fiber optics but wireless intended to replace cables and to offer a stable connection in a healthier and safer environment lifi is developing in various sectors such as aerospace education medical offices and administrative buildings or transportation oled comp brightly reinventing the way we connect

so we have the infrastructure there look look at the ceiling you see all these lightbulbs go to the main floor you see these lightbulbs can we use them for communications Wi-Fi is life to most of people but what if Internet is provided through light sounds awesome right this is what life is all about basically your light bulb will act as your router it stands for light fidelity and works as visible light communication system or we can say VLC which runs wireless communication through light the travel at very high speed VLC is not newly introduced actually Alexander Graham Bell may be better known as the person who invented VLC with the first practical telephone known as photo phone these photo phone used the transmission of human speech on a beam of light in the same path professor Harald Haas is pioneering his own light centric wireless communication system called life I now when we are comparing speed Wi-Fi is hundred times faster than Wi-Fi in 2011 professor Harold at the TED talks demonstrated his vision for the future of wireless communication now let's talk about Wi-Fi well first I want to say that this is not recently introduced it has been talk from around 2000 when Japanese researchers proposed the concept of communication through visible light in early 20s the term Wi-Fi was first coined by professor Harald during TED talks in 2011 that's good how data is transmitted through light source but what's the difference between life I and Wi-Fi wireless fidelity or Wi-Fi runs on radio waves there are slight fidelity or life Ahrens on light waves now in Wi-Fi or in routers they require many components to generate frequencies like radio circuits antennas and complex receivers whereas in life I it uses direct modulation method simply as remote control units using infrared communication to control TV Wi-Fi uses common household lights to enabled data transfer boosting space of 100 gigabits per second this light waves coming to light source is invisible to human eye the collected information from transmitted data is then interpreted by receiver this is conceptually similar to decoding Morse code but in much faster rate so in speed connectivity data transfer life I leave Wi-Fi in dust but what if we turn off light or there is no electricity if all power to light is turned off there is no life I the sly fireworks in dark area or dark room the answer to this is LED bulb can be dim low enough that room can appear dark there will be an advantage to use life I wear radio frequency waves don't reach like metal for example elevator there are many applications well life I can be used like Airlines dance areas due to low interference underwater and operation theater in hospitals other limitation is that it can travel only up to 10 meters while Wi-Fi up to 35 meters based on antennas LED bulb or any light source producing light waves can travel through walls like radio waves but very sly fi it has been predicted that life I will release to public by 2022 that's all guys thanks for watching if like a video give the thumbs up consider subscribing and see you next time