Forget Wi-Fi. Meet the new Li-Fi Internet | Harald Haas

翻译人员: Ziyu Zhao 校对人员: Chenfei Zhang

I would like to demonstrate for the first time in public

我想要第一次向公众证明

that it is possible to transmit a video

视频可以由一台LED台灯

from a standard off-the-shelf LED lamp

to a solar cell with a laptop acting as a receiver.

传送至太阳能电池板上， 并由一台手提电脑接收

There is no Wi-Fi involved, it's just light.

没有Wi-Fi介入，只是光

And you may wonder, what's the point?

那么你可能想知道， 这样做有什么意义？

And the point is this:

意义就是：

There will be a massive extension of the Internet

将来互联网会大规模覆盖

to close the digital divide,

“数字鸿沟“将不复存在

and also to allow for what we call "The Internet of Things" --

并且让我们所说的“物联网”变为可能——

tens of billions of devices connected to the Internet.

数以亿计的设备连接到互联网

In my view, such an extension of the Internet can only work

在我看来，互联网的大程度扩张

前提是需要基本保证“能源中性化” （指尽量减少能源消耗）

if it's almost energy-neutral.

This means we need to use existing infrastructure as much as possible.

这就是说， 我们需要 尽可能的多用现存的基础设施

And this is where the solar cell and the LED come in.

这就是为什么前面提到太阳能电池和LED

I demonstrated for the first time,

我之前第一次证明这件事

at TED in 2011,

是2011年在TED演讲

Li-Fi, or Light Fidelity.

我称它为Li-Fi，即光保真

Li-Fi uses off-the-shelf LEDs to transmit data incredibly fast,

用现存的LED灯可以极快地传递Li-Fi数据

and also in a safe and secure manner.

并且这种方式安全可靠

Data is transported by the light,

数据由光传输

encoded in subtle changes of the brightness.

由亮度的细微变化解码

If we look around, we have many LEDs around us,

如果我们环视四周，在我们身边有很多的LED灯

so there's a rich infrastructure of Li-Fi transmitters around us.

因此在我们周围有着非常丰富的Li-Fi发射装置

But so far, we have been using special devices -- small photo detectors,

但是目前，我们通常使用一个特别的设备—— 小型照片探测器

to receive the information encoded in the data.

来接收由数据解码出来的信息

I wanted to find a way to also use existing infrastructure

我想要找到一种方法，利用现有的基础设施

to receive data from our Li-Fi lights.

来接收Li-Fi灯发出的数据

And this is why I have been looking into solar cells and solar panels.

这也是为什么我一直研究 太阳能电池和太阳能电板

A solar cell absorbs light and converts it into electrical energy.

太阳能电池吸收光并转化成电能

This is why we can use a solar cell to charge our mobile phone.

这就是为什么我们能用 太阳能电池给我们的手机充电

But now we need to remember

但我们知道

that the data is encoded in subtle changes of the brightness of the LED,

数据是由LED亮度的微妙变化来编码的

so if the incoming light fluctuates,

所以如果入射的光有波动

so does the energy harvested from the solar cell.

那么太阳能电池收集的能量也有波动

This means we have a principal mechanism in place

这就意味着我们具备了一项基本原理：

to receive information from the light and by the solar cell,

信息通过光的传导，由太阳能电池板接收

because the fluctuations of the energy harvested

因为收集的能量波动 与传输的数据相对应

correspond to the data transmitted.

Of course the question is:

当然问题就在

can we receive very fast and subtle changes of the brightness,

我们是否能够收集到 非常迅速和微小的亮度变化

such as the ones transmitted by our LED lights?

比如通过我们的LED灯传递的那种

And the answer to that is yes, we can.

答案是 是的，我们可以

We have shown in the lab

我们在实验室已经展示

that we can receive up to 50 megabytes per second

我们能够接收达到每秒50MB的数据

from a standard, off-the-shelf solar cell.

通过一个标准的，现有的太阳能电池

And this is faster than most broadband connections these days.

这比目前最高速的宽带连接还要快

Now let me show you in practice.

现在让我来实践展示一下

In this box is a standard, off-the-shelf LED lamp.

在这个盒子里，是一个现有的标准LED灯

This is a standard, off-the-shelf solar cell;

这是一个现有的标准太阳能电池

it is connected to the laptop.

它连接到笔记本电脑上

And also we have an instrument here

这儿我们还有一个测量仪

to visualize the energy we harvest from the solar cell.

用来显示我们从太阳能电池收集的能量

And this instrument shows something at the moment.

现在这个仪表上有读数

This is because the solar cell already harvests light from the ambient light.

这是因为太阳能电池 已经开始从周围环境收集光了

Now what I would like to do first is switch on the light,

现在，首先我将把灯打开

and I'll simply, only switch on the light,

只是简单的打开灯，等一段时间

for a moment,

and what you'll notice is that the instrument jumps to the right.

你会注意到指针跳到了右边

So the solar cell, for a moment,

所以现在 太阳能电池 正在从这个人工光源接收能量

is harvesting energy from this artificial light source.

If I turn it off, we see it drops.

如果把它关掉，我们看到读数降回去了

I turn it on ...

再打开

So we harvest energy with the solar cell.

所以我们用太阳能电池收集了能源

But next I would like to activate the streaming of the video.

接下来， 我将要启动视频传导

And I've done this by pressing this button.

通过按下这个按钮来实现

So now this LED lamp here is streaming a video

所以现在这个LED灯正在通过亮度的细微变化传导一个视频

by changing the brightness of the LED in a very subtle way,

and in a way that you can't recognize with your eye,

这种亮度变化太快，不能用肉眼识别

because the changes are too fast to recognize.

But in order to prove the point,

为了证明这一点

I can block the light of the solar cell.

我可以阻挡太阳能电池接收的光

So first you notice the energy harvesting drops

首先你会注意到收集的能源下降了

and the video stops as well.

并且视频也停止了

If I remove the blockage, the video will restart.

如果我移开阻碍物， 视频会继续播放

(Applause)

（掌声）

And I can repeat that.

这个操作可以重复

So we stop the transmission of the video and energy harvesting stops as well.

所以当我们阻止视频的传输 能源收集也相应停止

So that is to show that the solar cell acts as a receiver.

这说明太阳能电池可以作为一个接收器

But now imagine that this LED lamp is a street light, and there's fog.

但是现在想像一下这个LED灯是街灯 并且周围有雾

And so I want to simulate fog,

我想模拟有雾的情况

and that's why I brought a handkerchief with me.

因此我随身带来一个手帕

(Laughter)

（笑声）

And let me put the handkerchief over the solar cell.

让我把手帕放到太阳能电池上

First you notice

首先你会注意到

the energy harvested drops, as expected,

能源收集量降低了，和预料的一样

but now the video still continues.

但是现在视频仍在继续播放

This means, despite the blockage,

这意味着，尽管有阻碍物

there's sufficient light coming through the handkerchief to the solar cell,

还是有足够的光穿过手帕到太阳能电池

so that the solar cell is able to decode and stream that information,

因此太阳能电池仍然 能够解码、传导数据信息

in this case, a high-definition video.

甚至是我们现在用的高清视频信息

What's really important here is that a solar cell has become a receiver

重要的是 太阳能电池 在这里成为了一个接收器

for high-speed wireless signals encoded in light,

接收编码成光的高速无线信号

while it maintains its primary function as an energy-harvesting device.

同时也保持了它作为 能源收集设备的基本功能

That's why it is possible

这就是说，屋顶上那些现有的太阳能电池

to use existing solar cells on the roof of a hut

to act as a broadband receiver

可以用来作为宽带网络的接收器

from a laser station on a close by hill, or indeed, lamp post.

信号可以来自靠近山坡的 激光站，或者街边的路灯

And It really doesn't matter where the beam hits the solar cell.

哪里的光束到达太阳能电池并不要紧

And the same is true

并且实际上

for translucent solar cells integrated into windows,

窗户上安装的半透明太阳能电池

solar cells integrated into street furniture,

安装在街道设施上的太阳能电池

or indeed, solar cells integrated into these billions of devices

甚至安装在成千上万 其他设备上的太阳能电池

that will form the Internet of Things.

它们将会形成物联网

Because simply,

这是因为我们不想经常给这些设备充电

we don't want to charge these devices regularly,

or worse, replace the batteries every few months.

更不想每几个月就要更换电池

As I said to you,

我之前说

this is the first time I've shown this in public.

这是我第一次向公众展示这些

It's very much a lab demonstration,

这次展示可以说是一个实验证明

a prototype.

一个原型

But my team and I are confident that we can take this to market

但是我和我的团队有信心 接下来两到三年，这项产品会进入市场

within the next two to three years.

And we hope we will be able to contribute to closing the digital divide,

希望我们能够对终结“数字鸿沟”做出贡献

and also contribute

并且帮助成千上万的设备连接到互联网

to connecting all these billions of devices to the Internet.

And all of this without causing

而且所有设备不会造成巨大的能源消耗

a massive explosion of energy consumption --

because of the solar cells, quite the opposite.

因为我们将利用现有的太阳能电池

Thank you.

谢谢

(Applause)

（掌声）