Forget Wi-Fi. Meet the new Li-Fi Internet
-
0:01 - 0:04I would like to demonstrate
for the first time in public -
0:04 - 0:08that it is possible to transmit a video
-
0:08 - 0:12from a standard off-the-shelf LED lamp
-
0:12 - 0:18to a solar cell with a laptop
acting as a receiver. -
0:18 - 0:21There is no Wi-Fi involved,
it's just light. -
0:21 - 0:24And you may wonder, what's the point?
-
0:24 - 0:26And the point is this:
-
0:26 - 0:29There will be a massive
extension of the Internet -
0:29 - 0:32to close the digital divide,
-
0:32 - 0:36and also to allow for what we call
"The Internet of Things" -- -
0:36 - 0:39tens of billions of devices
connected to the Internet. -
0:39 - 0:43In my view, such an extension
of the Internet can only work -
0:43 - 0:46if it's almost energy-neutral.
-
0:46 - 0:51This means we need to use existing
infrastructure as much as possible. -
0:51 - 0:56And this is where the solar cell
and the LED come in. -
0:57 - 0:59I demonstrated for the first time,
-
0:59 - 1:01at TED in 2011,
-
1:01 - 1:03Li-Fi, or Light Fidelity.
-
1:04 - 1:10Li-Fi uses off-the-shelf LEDs
to transmit data incredibly fast, -
1:10 - 1:12and also in a safe and secure manner.
-
1:13 - 1:16Data is transported by the light,
-
1:16 - 1:19encoded in subtle changes
of the brightness. -
1:20 - 1:24If we look around,
we have many LEDs around us, -
1:24 - 1:29so there's a rich infrastructure
of Li-Fi transmitters around us. -
1:29 - 1:35But so far, we have been using
special devices -- small photo detectors, -
1:35 - 1:38to receive the information
encoded in the data. -
1:39 - 1:43I wanted to find a way to also use
existing infrastructure -
1:43 - 1:46to receive data from our Li-Fi lights.
-
1:46 - 1:51And this is why I have been looking into
solar cells and solar panels. -
1:51 - 1:56A solar cell absorbs light
and converts it into electrical energy. -
1:57 - 2:02This is why we can use a solar cell
to charge our mobile phone. -
2:02 - 2:03But now we need to remember
-
2:03 - 2:09that the data is encoded in subtle changes
of the brightness of the LED, -
2:09 - 2:13so if the incoming light fluctuates,
-
2:13 - 2:16so does the energy harvested
from the solar cell. -
2:17 - 2:20This means we have
a principal mechanism in place -
2:20 - 2:26to receive information from the light
and by the solar cell, -
2:26 - 2:29because the fluctuations
of the energy harvested -
2:29 - 2:31correspond to the data transmitted.
-
2:32 - 2:34Of course the question is:
-
2:34 - 2:38can we receive very fast and subtle
changes of the brightness, -
2:38 - 2:42such as the ones transmitted
by our LED lights? -
2:43 - 2:46And the answer to that is yes, we can.
-
2:47 - 2:48We have shown in the lab
-
2:48 - 2:52that we can receive up to 50
megabytes per second -
2:52 - 2:54from a standard, off-the-shelf solar cell.
-
2:55 - 2:59And this is faster than most
broadband connections these days. -
2:59 - 3:03Now let me show you in practice.
-
3:05 - 3:09In this box is a standard,
off-the-shelf LED lamp. -
3:11 - 3:14This is a standard,
off-the-shelf solar cell; -
3:14 - 3:16it is connected to the laptop.
-
3:17 - 3:19And also we have an instrument here
-
3:19 - 3:23to visualize the energy
we harvest from the solar cell. -
3:23 - 3:26And this instrument shows
something at the moment. -
3:26 - 3:30This is because the solar cell already
harvests light from the ambient light. -
3:31 - 3:34Now what I would like to do first
is switch on the light, -
3:34 - 3:36and I'll simply, only switch on the light,
-
3:36 - 3:38for a moment,
-
3:38 - 3:42and what you'll notice is that
the instrument jumps to the right. -
3:43 - 3:45So the solar cell, for a moment,
-
3:45 - 3:48is harvesting energy
from this artificial light source. -
3:49 - 3:52If I turn it off, we see it drops.
-
3:52 - 3:53I turn it on ...
-
3:53 - 3:56So we harvest energy with the solar cell.
-
3:57 - 4:02But next I would like to activate
the streaming of the video. -
4:03 - 4:06And I've done this
by pressing this button. -
4:06 - 4:10So now this LED lamp here
is streaming a video -
4:11 - 4:15by changing the brightness of the LED
in a very subtle way, -
4:15 - 4:17and in a way that you can't
recognize with your eye, -
4:17 - 4:20because the changes
are too fast to recognize. -
4:21 - 4:24But in order to prove the point,
-
4:24 - 4:27I can block the light of the solar cell.
-
4:28 - 4:31So first you notice
the energy harvesting drops -
4:31 - 4:33and the video stops as well.
-
4:33 - 4:37If I remove the blockage,
the video will restart. -
4:37 - 4:44(Applause)
-
4:44 - 4:46And I can repeat that.
-
4:46 - 4:51So we stop the transmission of the video
and energy harvesting stops as well. -
4:51 - 4:56So that is to show that the solar cell
acts as a receiver. -
4:56 - 5:01But now imagine that this LED lamp
is a street light, and there's fog. -
5:02 - 5:04And so I want to simulate fog,
-
5:04 - 5:07and that's why I brought
a handkerchief with me. -
5:07 - 5:09(Laughter)
-
5:09 - 5:13And let me put the handkerchief
over the solar cell. -
5:14 - 5:16First you notice
-
5:16 - 5:20the energy harvested drops, as expected,
-
5:20 - 5:22but now the video still continues.
-
5:23 - 5:25This means, despite the blockage,
-
5:25 - 5:29there's sufficient light coming through
the handkerchief to the solar cell, -
5:29 - 5:35so that the solar cell is able to decode
and stream that information, -
5:35 - 5:37in this case, a high-definition video.
-
5:39 - 5:45What's really important here is that
a solar cell has become a receiver -
5:45 - 5:48for high-speed wireless signals
encoded in light, -
5:48 - 5:53while it maintains its primary function
as an energy-harvesting device. -
5:54 - 5:56That's why it is possible
-
5:56 - 6:00to use existing solar cells
on the roof of a hut -
6:00 - 6:03to act as a broadband receiver
-
6:03 - 6:07from a laser station on a close by hill,
or indeed, lamp post. -
6:08 - 6:11And It really doesn't matter
where the beam hits the solar cell. -
6:12 - 6:13And the same is true
-
6:13 - 6:17for translucent solar cells
integrated into windows, -
6:17 - 6:20solar cells integrated
into street furniture, -
6:20 - 6:25or indeed, solar cells integrated
into these billions of devices -
6:25 - 6:27that will form the Internet of Things.
-
6:27 - 6:28Because simply,
-
6:28 - 6:31we don't want to charge
these devices regularly, -
6:31 - 6:34or worse, replace the batteries
every few months. -
6:34 - 6:36As I said to you,
-
6:36 - 6:38this is the first time
I've shown this in public. -
6:39 - 6:41It's very much a lab demonstration,
-
6:41 - 6:42a prototype.
-
6:42 - 6:46But my team and I are confident
that we can take this to market -
6:46 - 6:48within the next two to three years.
-
6:48 - 6:54And we hope we will be able to contribute
to closing the digital divide, -
6:54 - 6:55and also contribute
-
6:55 - 6:58to connecting all these billions
of devices to the Internet. -
6:58 - 7:00And all of this without causing
-
7:00 - 7:02a massive explosion
of energy consumption -- -
7:02 - 7:05because of the solar cells,
quite the opposite. -
7:05 - 7:06Thank you.
-
7:06 - 7:11(Applause)
- Title:
- Forget Wi-Fi. Meet the new Li-Fi Internet
- Speaker:
- Harald Haas
- Description:
-
What if we could use existing technologies to provide Internet access to the more than 4 billion people living in places where the infrastructure can't support it? Using off-the-shelf LEDs and solar cells, Harald Haas and his team have pioneered a new technology that transmits data using light, and it may just be the key to bridging the digital divide. Take a look at what the future of the Internet could look like.
- Video Language:
- English
- Team:
- closed TED
- Project:
- TEDTalks
- Duration:
- 07:24
Brian Greene edited English subtitles for A breakthrough new kind of wireless Internet | ||
Brian Greene edited English subtitles for A breakthrough new kind of wireless Internet | ||
Brian Greene edited English subtitles for A breakthrough new kind of wireless Internet | ||
Brian Greene approved English subtitles for A breakthrough new kind of wireless Internet | ||
Brian Greene edited English subtitles for A breakthrough new kind of wireless Internet | ||
Brian Greene edited English subtitles for A breakthrough new kind of wireless Internet | ||
Brian Greene edited English subtitles for A breakthrough new kind of wireless Internet | ||
Camille Martínez accepted English subtitles for A breakthrough new kind of wireless Internet |