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Networking China Hardware Hacking Build

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."
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Chinese Professor Builds Li-Fi System With Retail Parts

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  • by Anonymous Coward

    Wasn't my palm pilot doing this years ago via infra red?

  • ...am I supposed to maintain my pasty-pale complexion if I have any light sources on? The tan from my six monitors and blue LEDs is already bad enough!
  • by Anonymous Coward on Tuesday November 05, 2013 @09:02AM (#45335183)

    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.

    • by gl4ss ( 559668 )

      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.

    • 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.

      • Not to mention infrared (IrDA) - it was common on PDAs (and you could connect to an IrDA printer, for example)

    • >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.

    • by mlts ( 1038732 ) *

      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

    • 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.


      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.

      • Sometimes an old solution can solve a new problem. Back in the IrDA days there wasn't as much radio interference. With a new implementation (higher speeds, more devices, maybe some beam forming technique) this could help.
        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.
        • 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.

    • by AmiMoJo ( 196126 ) *

      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

  • Never heard of RiFi.
  • by Mirar ( 264502 )

    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?

    • by mlts ( 1038732 ) *

      That's just for malware, which arguably is the most reliable software made these days.

      • by Mirar ( 264502 )

        Oh, I see. And the Li-fi is maybe too bright for malware, that needs to stay in the shadows? :)

      • by unitron ( 5733 )

        That's just for malware, which arguably is the most reliable software made these days.

        Congratulations, you just wrote your new sig file.

  • 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)

    by Dan East ( 318230 ) on Tuesday November 05, 2013 @09:28AM (#45335347) Homepage Journal

    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.

    • by mlts ( 1038732 ) *

      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

      • by tibit ( 1762298 )

        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.

        • by mlts ( 1038732 ) *

          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.

    • Bluetooth has sort of replaced it

      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

    • News just in, IrDA isn't an acronym it's an abbreviation, sometimes the two are the same but usually they are not as is the case here.
  • 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

    • by nurb432 ( 527695 )

      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

  • 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.

    • by tibit ( 1762298 )

      And let's not forget the clacks towers [wikia.com]!

    • Ever hear of rain, snow, smoke, smog, fog, dust, or deciduous trees? (Ok, maybe not, this is /. But some people must emerge from their moms' basements occasionally to reload on pizza and Jolt). Long range free space optical transmission is a PITA outdoors unless you can afford to wait around a few days for the weather to change. Indoors, there may be a place for it if you can make it cheaper than cables (installed and operated). Might be a good fit for convention centres. To really work well, you'll want
  • by wonkey_monkey ( 2592601 ) on Tuesday November 05, 2013 @10:28AM (#45335897) Homepage

    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.

  • could anyone in the know enlighten us how the uplink is supposed to work? TFA doesn't clarify.
  • by csumpi ( 2258986 ) on Tuesday November 05, 2013 @10:39AM (#45336015)
    from TFA:

    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.

    • We have a whole bunch of other solutions, like bluetooth for example, that's low power, invisible, and go way further than that.

      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.

  • WTF? My early 1990s era laptops had this. How is this NEW?
  • Its been done before for less

    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]

  • 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.

  • 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].

Pause for storage relocation.