Chinese Professor Builds Li-Fi System With Retail Parts 155
alphadogg writes "The equipment is big and expensive, with the research costs at almost $500,000. But by just using retail components, Chinese professor Chi Nan has built her own Li-Fi wireless system that can use LED lights to send and receive Internet data. "I bought the lights from Taobao," she said, referring to the Chinese e-commerce site. The professor from Fudan University showed off the technology on Tuesday at the China International Industry Fair in Shanghai. Unlike traditional Wi-Fi routers that use radio signals, Chi's system relies on light to send and receive data wirelessly. Others scientists, especially in the U.K., have also been researching the technology, and dubbed it "Li-Fi". But rather than develop specialized hardware, Chi bought off-the-shelf retail parts to create her system."
Infrared? (Score:1)
Wasn't my palm pilot doing this years ago via infra red?
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Yeah, at 400 baud.
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Well, that will solve everything then!
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Who cares. It's a direct line of sight issue, and unless we all start wearing beanies with IR antennas on top of them, it will never be a good solution.
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But how... (Score:1)
What's All The Fuss? (Score:5, Insightful)
Can someone tell me what all the fuss about "LiFi" is? We've had free space optical networking for decades. It's not new and it's not a good general networking solution, especially for household use, which the LiFi buzz seems to be implying.
I just don't see a broad use case for this and I don't understand why it is getting so much press. Will they, next week, "discover" that they can make it work in the dark by using infrared TV remote controls?
P.S. As someone who is jumping through hoops and going to great lengths to eliminate flicker in household LED bulbs, the thought of intentionally flickering the light, even at high frequencies, does not sit well with me.
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what you mean they invented irda already?
I suppose for it to be realy lifi it would have to have ethernet kind of tolerance for multiple devices.
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Can someone tell me what all the fuss about "LiFi" is?
It seems that everytime things hit a lull in the industry, there is a surge in old technology with new acronyms (re-post!). We've had optical communications in our remote controls (and the Linux kernel) for decades. Acoustic networking is older than I am yet the latest BIOS infector [arstechnica.com] is being pushed as some kind of new magic-mystery-machine. It's unique for a virus to replicate acoustically, but the technology isn't new to anyone who has used a modem.
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Not to mention infrared (IrDA) - it was common on PDAs (and you could connect to an IrDA printer, for example)
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>We've had free space optical networking for decades.
I hope renewed interest both raises speeds and reduces cost of FSO, as someone who runs a lot of p-t-p wireless links the more options the better.
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This isn't new technology either. Ages ago (circa 1989), there was a LocalTalk [1] adapter that mounted on top of a cubicle. You mounted all the adapters, focused them all on a wall that all of them could see, a green light would come on when they were happy, then tightened them in place. From there, all the machines would yak happily with each other via infrared. This worked quite well in a cube farm, and one could use infrared adapters so traffic could be carried to a different room.
I'm sure "LiFi" ha
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Can someone tell me what all the fuss about "LiFi" is? We've had free space optical networking for decades. It's not new and it's not a good general networking solution, especially for household use, which the LiFi buzz seems to be implying.
This.
Hell, the Romans had an optical communication network that stretched across a good portion of their empire, in the form of a chain of signal towers equipped with torches and mirrors.
If "Li-Fi" is news, then please excuse me while I go hit the bath and discover buoyancy.
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Once upon a time long distance communication was done with light. When copper became feasible we started using electrons. However; most miles of communication are once again done with light.
Sometimes the old solutions solve the new problems.
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The implementation that this researcher has come up with may be new and novel, and I respect that.
My problem is with the media, who is acting like using visible light for data communications is some sort of previously unknown wündertech.
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Actually it is ideal for home use. The 2.4GHz band is like two heavy metal concerts trying to drown each other out while Justin Bieber fans scream wildly on either side. 5GHz is okay for now but eventually will get crowded too. Light has the advantage of not travelling through walls.
Lifi won't flicker either. Consider that a pathetic 1Mb/sec with encoding is going to require at least 100KHz flickering, which is orders of magnitude above what you could ever hope to see. Furthermore the flickering that is the
Is it me? (Score:1)
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Yep, it's quite the opposite. If it was limited to working in complete darkness, one could save a little bit of money by getting rid of IR-pass filters that those devices need.
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Yep, it's quite the opposite. If it was limited to working in complete darkness, one could save a little bit of money by getting rid of IR-pass filters that those devices need.
If it's going to use "visible" light, wouldn't it need IR and UV blocking filters?
Although since using light in a completely dark room kind of does away with the whole "completely dark" thing, I may have misunderstood where you were going with that.
Si-fi (Score:1)
I thought the trend these days was to build a computer network using the built-in speakers and microphones, outside of the human hearing range. ;)
Also, that looks indeed like specialized hardware?
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That's just for malware, which arguably is the most reliable software made these days.
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Oh, I see. And the Li-fi is maybe too bright for malware, that needs to stay in the shadows? :)
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That's just for malware, which arguably is the most reliable software made these days.
Congratulations, you just wrote your new sig file.
Great use of technology (Score:2)
Ship it to the kids in Afghanistan that wanted to hook up their C-64s to the Internet to watch movies. Good thing they were stored buried underground all this time.
IrDA (Score:5, Interesting)
News just in: IrDA wants its acronym back. On a more serious note, I really did like IrDA. It was slow as crap and the range sucked, but at one point in time, pretty much EVERYTHING had IrDA support. Laptops, cell phones, PDAs, HPCs, etc. You could buy serial dongles to add to any PC for $5 or so. It was the go-to fallback to transfer a file or data between two devices that had disparate storage card types (PC-Card vs CF cards, etc), or you didn't have cables to connect them up directly. Bluetooth has sort of replaced it, but you can't just bit-bang communication with a bluetooth device using a microcontroller and two 25 cent components. Plus Bluetooth has been implemented by OEMs as more of a method to connect dumb peripherals than a method of communicating directly between devices.
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I liked IrDA because it was secure. If you wanted to copy data privately between one device and another, you placed the IR ports nearby each other, and started a transfer. Unlike Bluetooth, an eavesdropping device has to not be just present, but close enough (within a couple feet) of both devices in order to get any significant data.
Plus, IrDA is simple. It takes a lot less to get it communicating data than even a basic USB slot, so it can be a method to upgrade/configure a microcontroller without having
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As long as you have an open window into a room where IrDA is in use, and are within a couple hundred feet, all you need is a $200 reflector telescope from WalMart and you can receive it using off-the-shelf gear. Been there, done that as a proof of concept. It's not secure unless you run encrypted protocols on top of it.
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Very true. However, if worse comes to worst, I can go into a meeting room. Of course, it can be done, but the telescope and transceiver are a lot less common than a smartphone with a BT or Wi-Fi antenna.
For a Diffie-Hellman key exchange, it is ideal. One can watch the exchange take place, but it would be very difficult to MITM it. Implementing NFC to have two devices validate their public keys is a lot simpler than trying to do the same over NFC, or even audio.
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When I see every new laser printer coming out with bluetooth included, I'll agree with you. Until then, no.
IrDA didn't have a lot of practical uses, but back in college, I was God-like for being able to write-up documents with full formatting, embedded charts, graphs, and images on my pocket-sized Psion PDA, and just use IrDA to print it out, right there in class, the lab, or at the library. The time saved was tremendous versus scribbling notes, going home to type it up a
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Now try lasers! (Score:2)
The first time I saw this basic thing done, in a hacky way, was between the ham radio clubs of my university and our neighboring university, in... the late 1980s.
They took two helium-neon laser tubes (laser diodes not being as available to hackers yet), two photosensors, and two little shutter-like things that modulated light proportionally to some voltage. Then they took two acoustic modems. They hooked the sound-generation output to the thing that modulated the light and the sound input to the photosen
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We did it back in the 70s.... with voice. Could have done it again later when acoustic modems became available to the average person.
IrDA existed in the 80s and 90s.. And was a life saver when the parallel port went out on my *expensive* laser printer.. It had irDA... was great for syncing my PDA to my PC and not having to futz around with cables. Could even pipe it thru a fiber in a light-noisy environments.
Xerox was experimenting with it for office transmission back in the 80's too, trying to make 'unive
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Basically you modulate them fully, but they respond with a shallow-modulated optical output. Needs a bit of filtering at the receiving end to correct the roll-off.
Data Transmission in Glass, in Air: All the same (Score:2)
Been doing light transmission in glass fibers for decades. Early "air" transmission was signal flags & smoke, but transmitting data via in air has been done via lasers on various frequencies for decades too, initially to submerged submarines, albeit with a megawatt lasing tube.
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And let's not forget the clacks towers [wikia.com]!
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Meaningless comparisons FTW (Score:5, Insightful)
Chinese Professor Builds Li-Fi System With Retail Parts...
...which isn't as good as pro kit.
The equipment is big and expensive, with the research costs at almost $500,000.
Research costs don't tell you anything about the cost of "the equipment," whatever that refers to. A modern mobile phone might set you back $200, but you could easily make the research costs total several billion dollars depending how far you want to go back. If someone comes along with a couple of tin cans and a piece of string, I don't really see how that's automatically newsworthy.
But by just using retail components, Chinese professor Chi Nan has built her own Li-Fi wireless system that can use LED lights to send and receive Internet data.
There are plenty of things I can do with retail components that wouldn't be possible without prior billions being spent on research. That doesn't make me the King of Awesome (I am, but it's entirely unrelated).
FWIW, Chi's system works over about 3m, the hardware is large and heavy, and it achieves a speed of about 150mbps.
Upstream (Score:2)
"must be within three meters" (Score:3, Informative)
Because it is dependent on light, the technology can't penetrate walls or work in complete darkness. In Chi's case, the Li-Fi receiver must be within three meters of the router, and placed under the LED bulbs so that the sensor can read it.
Am I missing something here? If it can't work in total darkness, and the receiver has to be within 3 meters, what's the application for this? We have a whole bunch of other solutions, like bluetooth for example, that's low power, invisible, and go way further than that.
Sounds like a fun project, but doesn't seem more useful than building a cnc machine out of legos.
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Let me know when bluetooth hits "3.5 Gbps"...
And bluetooth really needs MORE power, because something like this can use your already-on LED lights in your house.
Something like this could make sense for any high-speed and mostly one-way communications. Streaming video to your TVs (or tablets, phones, etc.) around the house is an obvious use that WiFi does very, very poorly.
1990 called (Score:2)
you missed the point (Score:2)
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Its been done before for less (Score:2)
Its been done before for less
Microprocessor
http://www.linux-cae.net/Projects/Serial/Laser/laser.htm [linux-cae.net]
Aurdio Laser Modem:
http://makezine.com/2008/08/13/laser-modem-with-an-ardui/ [makezine.com]
Raspberry Pi
http://www.ohmpie.com/lasermodemvideo/ [ohmpie.com]
Features so awesome it was REMOVED from laptops (Score:1)
Seriously, using light to communicate is so awesome that ... laptops STOPPED carrying the stupid IrDA port that worked like shit. Its not impressive that someone did it now with shit that radio shack has been selling kids for 30 years. I know, cause I could by the parts to build and do this at radio shack 25 years ago, I know since I did just that for my TRS-80. I wasn't the first then, since I was following the directions in some magazine.
Line of sight? (Score:1)
I assume the technology is for export, because line of sight in China should be good for, oh, about twenty feet or so [chinaairdaily.com].
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Only if you use laser LEDs that are powerful enough to burn through them.
Comment removed (Score:5, Informative)
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you really need CAT5e installed (outside the walls unfortunately).
You see, I got this here tool that can tunnel through walls.
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"You see, I got this here tool that can tunnel through walls."
Man, that's one powerful ssh client.
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Depends on the material of the wall I would think.
My SSH client tunnels through firewalls all the time!
Re: does it work through walls? (Score:1)
Not me I tunnel with diodes.
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Only if you use laser LEDs that are powerful enough to burn through them.
Unfortunately lasers that powerful have to be cooled by a continuous saline solution stream.
Although I hear some research has been done in that area that involves mounting them on large, constantly moving ocean creatures.
Re:does it work through walls? (Score:5, Interesting)
A wireless medium that doesn't use something capable of penetrating through walls would actually be an advantage in these kinds of environments. Granted, to be practical it would require peoples' devices to have both WIFI and LIFI, but they often have both WIFI and copper capability now anyway, so more than one interface isn't a stretch.
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So how is it different than infrared, which has been in use for quite some time?
Re:does it work through walls? (Score:5, Interesting)
Nothing really. It's a new buzzword that everyone is oogling. we were getting 4mbps over IR point to point using PVC and some lenses to steal internet from the college back in the early 90's. One of the buildings was visible from our rental so we ran wires and had an old linux PC at each end using the DB15 ports on the old ethernet cards we found and set up a photodiode and an IR led on each end to set up an optical link. WE actually used visible LED's to start with to set everything up, and then went IR for stealth.
Worked great we had the fastest internet around for a house with 12 random nerds in it. I will bet that the transmitter portion is still on the roof of that school building 20 some years later.
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Infrared currently is used as a point-to-point connection where (most of the time) there has to be a clear (as in: only air) path from one node to the other. It's mostly used as a device-to-device type of connection, not as a network of devices.
Li-Fi should integrate into the lighting plan of rooms, should be capable of operation using reflections instead of direct point-to-point. Of course, reflections and re-transmissions probably cause signal degradation if no filter capability exists so the software pro
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Infrared currently is used as a point-to-point connection where (most of the time) there has to be a clear (as in: only air) path from one node to the other. It's mostly used as a device-to-device type of connection, not as a network of devices.
Li-Fi should integrate into the lighting plan of rooms, should be capable of operation using reflections instead of direct point-to-point. Of course, reflections and re-transmissions probably cause signal degradation if no filter capability exists so the software protocols should be able to compensate or, if unable, scale back to lower network speeds. The same for 'foreign' light sources (the sun included). Individual light points should act as repeaters with one point in a room connected to the 'regular' network being enough to provide the entire room (however large it may be) with full network access. At least, those are the 'promises' I heard about Li-Fi.
And, indeed, being unable to penetrate walls can be an advantage.
Precisely. Instead of setting up a separate funny-looking wart on the ceiling or some such, the room light itself is a transceiver. As a bonus, for room illumination it would draw about 1/4 the power of equivalent incandescents, based on what I've seen for sale lately.
Even with IR, I routinely bounce off a wall or mirror for my remotes. Unless the room is painted black, chances are that a visible frequency will reflect even better. Of course, that also means that it will go through windows, so keep the shr
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So how is it different than infrared, which has been in use for quite some time?
It's not, it's different from infrared.
But mostly just in carrier frequency.
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IR doesn't always need to be direct line-of-sight. Most peoples' experience with IR is from TV remotes which generally do have to be aimed, but I've got a couple of devices whose remotes are powerful enough that pointing them just about anywhere in the room will control the device. It is possible to use refraction if the setup is designed for it.
And if you have a white or light-colored ceiling or wall, you can use reflection as well.
We have an overhead light fixture in the same room as the main television, and it has a flat white diffuser under its 4 incandescent bulb sockets, and I can carom a remote beam off of that quite easily if I'm standing in the right spot.
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The solution then is high powered wall penetrating lazers.
In fact the solution is always lazers. For everything.
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But how do you get the sharks to hold still long enough to get a signal across???
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Lazers.
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You jest, but if the fixtures are cheap enough, it's a great way to do wireless networking *without* the myriad of security issues that plague traditional RF-based WiFi - namely, the signal escaping your house. Knowing the Li-Fi signal stops at the wall (and can probably be tuned so very little spills out the windows) means to actually break into the network requires physical presence.
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No. That's a feature. If an attacker can't see into your room, he can't see your network.
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Homes in the USA also have windows...
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Homes in the USA also have windows...
Windows also have blinds and/or shades.
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And even with your blinds fully closed, it's still easy to tell whether the lights are on or off.
Very few people have dark, black-out curtains, but that's want you need to be sure data isn't leaking out of the building.
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Re: does it work through walls? (Score:1)
People who live in glass houses...
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We have Chinese-descended people in the USA. The joke might be at the expense of the PRC, but it is not about race at all.
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i only ask because homes in the USA have them
Yeah unlike those dumb Chinese huh? You're racist
The word you're looking for is bigoted. The Chinese are not a race.
Re:Race? Indeed (Score:3)
Over 170 ethnic groups inhabit inside China's borders. The only race that controls China is the ultra wealthy Communist Party.
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I think it is because some people confuse "Chinese" with the Han race. It is similar to how Muslims are always classified as Arabs, even though Persians are a different ethnic group.
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Historically, Persians were Zoroastrian, not Muslim, right?
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Historically, no one was Muslim before approximately 600ad. So if that's your test then Arabs fail it just the same as Persians.
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i only ask because homes in the USA have them
Yeah unlike those dumb Chinese huh? You're racist
The word you're looking for is bigoted. The Chinese are not a race.
Bigotry refers to rejecting another person's views with no consideration when they differ from your own simply because they differ from your own.
Bigotry has nothing to do with hatred or animosity. It has to do with stubbornness, ego, zealotry, etc.
Re: does it work through walls? (Score:1)
One who studies bigonometry
Betcha it works through water.... (Score:1)
The "talk on a beam of light" has been a popular science fair project since LED's and photodiodes became available.
Nothing new, but the idea of having divers being able to communicate underwater, voice or texts, seems useful. You wanna text someone? Use your flashlight. Light him up. The light contains the message.
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Re:Ah So (Score:5, Insightful)
You're thinking of Japan... pornography is illegal in China, and tentacles aren't a part of their culture to begin with. Also, the "Chinaman" you speak of is a woman.
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Yeah, pornography is illegal, yet whilst I was managing the I.T. department at kink.com I would constantly see a not insignificant number of mbps going to china from our CDN.
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Also, what's with all the racist jokes in this thread?
Seems like an unusually high number compared to other stories involving Chinese people.
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That's simply not true. Pornography is legal in Japan. The display of genitals in pornography is not, which they circumvent using pixelation. Even if what you say were true, the cultural significance of tentacles in sexuality predates laws on pornography. See: http://en.wikipedia.org/wiki/The_Dream_of_the_Fisherman's_Wife [wikipedia.org]
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Even though it was an AC, the parent here was actually funny and should have been modded up.
No, it is not funny. Switching the "R" and "L" sounds is Japanese thing, not Chinese.
What the starving Chinese ...
The Chinese are not starving. This is 2013, not 1961 [wikipedia.org]. There are more middle class people in China than in America.
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There are more middle class people in China than in America.
With a population about 4 times greater, I'd hope so.
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The Chinese are not starving. This is 2013, not 1961 [wikipedia.org]. There are more middle class people in China than in America.
There are more every class people in China than in America.
Vs. anyone with more than half a brain, bullshit statistics do not work.
Re: mod parent up (Score:1)
As I've seen it explained, China is a country pretty similar to the US; plus a couple of billion subsistence farmers.
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1) correct. The /r/ /l/ differentiation distinction is problematic for Japanese and Thai speakers especially. The Thais lump the /n/ in as well. Koreans also have the problem in some phonetic contexts. /r/ is remarkably different from the western European /r/
But, I should add that the Chinese
2) while almost correct, as in "yes the Chinese today do have a robust middle class while we have a moribund and retrograde middle class"
saying that they have "more" mile class people than we do ignores the fact that th
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Light Beam Communications, copyright 1975, Forrest Mims, ISBN 978-0672211478 Howard W. Sams
I was wondering when someone would bring him up, although I think his chief claim to fame in that area was using Light-Emitting Diodes as detectors of light, rather than just as emitters of it.