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Chinese Professor Builds Li-Fi System With Retail Parts

Posted by timothy on from the shine-on-crazy-diamond dept.

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."

155 comments

  1. SO REALLY IT IS RI-FI ?? by Anonymous Coward · · Score: -1

    You know being Chinese and all !!

  2. does it work through walls? by alen · · Score: -1, Flamebait

    i only ask because homes in the USA have them

    1. Re:does it work through walls? by Anonymous Coward · · Score: -1

      i only ask because homes in the USA have them

      Yeah unlike those dumb Chinese huh? You're racist

    2. Re:does it work through walls? by Anonymous Coward · · Score: 1

      Only if you use laser LEDs that are powerful enough to burn through them.

    3. Re:does it work through walls? by TWX · · Score: 4, Interesting

      I would bet that it's more tuned to commercial markets. For density in classrooms it's not uncommon to place two WAPs in one room for the express purposes of serving the 30+ devices in that room, and with the bleed-over between rooms all of the WAPs have to step-down their power to avoid interfering with each other.

      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.

      --
      Do not look into laser with remaining eye.
    4. Re:does it work through walls? by sg_oneill · · Score: 0

      i only ask because homes in the USA have them

      The solution then is high powered wall penetrating lazers.

      In fact the solution is always lazers. For everything.

      --
      Excuse the Unicode crap in my posts. That's an apostrophe, and slashdot is busted.
    5. Re:does it work through walls? by dreamchaser · · Score: 0

      But how do you get the sharks to hold still long enough to get a signal across???

    6. Re:does it work through walls? by SJHillman · · Score: 1

      So how is it different than infrared, which has been in use for quite some time?

    7. Re:does it work through walls? by Lumpy · · Score: 4, 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.

      --
      Do not look at laser with remaining good eye.
    8. Re:does it work through walls? by Anonymous Coward · · Score: -1

      She'll be heralded as the inventor of Li-Fi in China now. That's how it works in Asia. Plagiarism and rip-off = invention. That's the ugly Ugly side of this. Otherwise though, great to see it!

      Hint: Asia didn't invent Li-Fi, or anything much for that matter- maybe a few fire crackers, some paper.. 5000 years of mediocrity and counting ..
      Western Civ. is older btw.

    9. Re: does it work through walls? by Anonymous Coward · · Score: 0

      On the plus side, this tech. will cut off the internet leech neighbor.

    10. Re:does it work through walls? by Anonymous Coward · · Score: -1, Troll

      You pull the racist card so much that eventually will loose any meaning at all. The same for homophobic, socialist, fascist et all.

    11. Re:does it work through walls? by MightyYar · · Score: 1

      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.

      --
      W..w..W - Willy Waterloo washes Warren Wiggins who is washing Waldo Woo.
    12. Re:does it work through walls? by Anonymous Coward · · Score: 0

      I guess I don't know for certian but the difference between this and IR would be IR needs direct line of sight where this would need general line of sight, so I don't think you need the LIFI to be aligned directly with each other, they can kind of just see each other, so it would work better with mutliple hosts sharing one receiever vs two devices with direct line of sight. And I'm guessing you don't need to 'aim' the lifi was much as you would the IR.

    13. Re:does it work through walls? by TWX · · Score: 1

      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.

      --
      Do not look into laser with remaining eye.
    14. Re:does it work through walls? by jiriw · · Score: 1

      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.

    15. Re: does it work through walls? by DigiShaman · · Score: 4, Informative

      Most homes in Chinese cities are in buildings like condominiums. Only the walls are poured concrete. That's because the walls are load-bearing as part of the design. At least that's my understanding. Regardless, getting WiFi access several rooms away can be real difficult if not impossible.

      If you're part if the growing middle class that plans on expanding network connectivity in the home, you really need CAT5e installed (outside the walls unfortunately).

      --
      Life is not for the lazy.
    16. Re: does it work through walls? by KiloByte · · Score: 1

      you really need CAT5e installed (outside the walls unfortunately).

      You see, I got this here tool that can tunnel through walls.

      --
      The creatures outside looked from Alt-Right to Antifa; but already it was impossible to say which was which.
    17. Re: does it work through walls? by Anonymous Coward · · Score: 0

      you really need CAT5e installed (outside the walls unfortunately).

      You see, I got this here tool that can tunnel through walls.

      So, you think no one will mind you putting holes through the concrete walls in your condo to run cabling? Maybe you can chip out a channel around the room so you can have a jack on the other side also.

    18. Re:does it work through walls? by Fallso · · Score: 1

      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.

    19. Re: does it work through walls? by Anonymous Coward · · Score: 0

      I do hope that you are not thinking about a thing called a drill? No, you could not be that stupid because that would mean that you have no clue what you are talking about and I am sure that you must have. So I assume you have a Kango hammer and you do not care about your neighbours or your wall.

    20. Re: does it work through walls? by Anonymous Coward · · Score: 0

      Don't be stupid. Drills drill through walls. For tunneling you use ants.

    21. Re:does it work through walls? by Anonymous Coward · · Score: 0

      Typically projectors have their photo-sensor aimed at the screen. This allows people to aim the remote at the screen just like they do with the TV.

    22. Re:does it work through walls? by Anonymous Coward · · Score: -1

      I really didn't take anything racist from that at all. If anything, it would be more about poverty and living conditions in China...but I didn't even take it that way at first. So many times on slashdot, someone is reprimanded for thinking a certain way and accused of living in the US. I thought the joke was about that. But this 'race card' game sounds quite interesting and fun. Let's play!

      When do you Chinese people still use primitive stick to eat? Can't you figure out how to make a wooden fork or spoon? Try it with wood first. I'd hate for you guys to get lead poisoning.

      When you get tired of living in homes without walls or with paper walls, my home is open to your attractive females here in the US. I also have openings for new male and female garden gnomes.

    23. Re:does it work through walls? by RabidReindeer · · Score: 1

      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 shrubbery patrolled!

    24. Re:does it work through walls? by Anonymous Coward · · Score: 0

      Back in the early days before satellite TV receivers had built-in DVRs, I had one with a built-in "IR blaster" which would bounce the signal off the opposite wall to control a VCR.

    25. Re: does it work through walls? by Concerned+Onlooker · · Score: 2

      "You see, I got this here tool that can tunnel through walls."

      Man, that's one powerful ssh client.

      --
      http://www.rootstrikers.org/
    26. Re: does it work through walls? by IndustrialComplex · · Score: 1

      Depends on the material of the wall I would think.

      My SSH client tunnels through firewalls all the time!

      --
      Out of modpoints but really liked a post? 1BDkF6TtmmeZ3yqXbz9yhdYVqRYnwFoXDj
    27. Re:does it work through walls? by tlhIngan · · Score: 1

      i only ask because homes in the USA have them

      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.

    28. Re:does it work through walls? by sexconker · · Score: 1

      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.

    29. Re: does it work through walls? by Anonymous Coward · · Score: 0

      So, you think no one will mind you putting holes through the concrete walls in your condo to run cabling?

      Yeah, I think no one will mind...

      First, go to the condo hassle administrator(s) and offer them a choice: silver or lead. Then, go to the neighbor(s) and offer them a choice: copper or lead.

      Maybe you can chip out a channel around the room so you can have a jack on the other side also.

      One could probably chip out a channel in no time flat, given enough lead.

    30. Re: does it work through walls? by Anonymous Coward · · Score: 0

      So does the upside-down-ternet!

    31. Re:does it work through walls? by istartedi · · Score: 1

      No. That's a feature. If an attacker can't see into your room, he can't see your network.

      --
      For all intensive purposes, "whom" is no longer a word. That begs the question, "who cares"?
    32. Re:does it work through walls? by unitron · · Score: 1

      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.

      --

      I see even classic Slashdot is now pretty much unusable on dial up anymore.

    33. Re:does it work through walls? by unitron · · Score: 1

      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.

      --

      I see even classic Slashdot is now pretty much unusable on dial up anymore.

    34. Re:does it work through walls? by unitron · · Score: 1

      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.

      --

      I see even classic Slashdot is now pretty much unusable on dial up anymore.

    35. Re:does it work through walls? by unrtst · · Score: 1

      Lazers.

    36. Re:does it work through walls? by Anonymous Coward · · Score: 0

      in fact, no one is...
      'race' is an artificial construct of poodles to look down upon cur dogs...
      we are ALL the same dog, just some dogs think their shit don't stink...

    37. Re:does it work through walls? by evilviper · · Score: 1

      If an attacker can't see into your room, he can't see your network

      Homes in the USA also have windows...

      --
      Slashdot gets worse every day... Pipedot: News for nerds, without the corporate slant
    38. Re:does it work through walls? by istartedi · · Score: 1

      Homes in the USA also have windows...

      Windows also have blinds and/or shades.

      --
      For all intensive purposes, "whom" is no longer a word. That begs the question, "who cares"?
    39. Re:does it work through walls? by evilviper · · Score: 1

      Windows also have blinds and/or shades.

      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.

      --
      Slashdot gets worse every day... Pipedot: News for nerds, without the corporate slant
    40. Re: does it work through walls? by LordWabbit2 · · Score: 1

      There is a better option

      --
      There are three kinds of falsehood: the first is a 'fib,' the second is a downright lie, and the third is statistics.
    41. Re: does it work through walls? by Anonymous Coward · · Score: 0

      Not in a dense environment. If you use a mass of homeplugs in an apartment block, adjacent clusters start interfering with each other (much like wifi), which shows up as speed reductions.

      Besides, LiFi can run at Gb/s, homeplug isn't there yet.

    42. Re:does it work through walls? by Palamos · · Score: 1

      For all 'intents and' purposes. Whom has it's place and in such places no other word is appropriate.

    43. Re: does it work through walls? by gzuckier · · Score: 1

      One who studies bigonometry

      --
      Star Trek transporters are just 3d printers.
    44. Re: does it work through walls? by gzuckier · · Score: 1

      Not me I tunnel with diodes.

      --
      Star Trek transporters are just 3d printers.
    45. Re: does it work through walls? by gzuckier · · Score: 1

      People who live in glass houses...

      --
      Star Trek transporters are just 3d printers.
  3. Infrared? by Anonymous Coward · · Score: 1

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

    1. Re:Infrared? by NatasRevol · · Score: 1

      Yeah, at 400 baud.

      --
      There are two types of people in the world: Those who crave closure
    2. Re:Infrared? by Anonymous Coward · · Score: 0

      IrDA actually went up to 4Mbps, so you are off by four orders of magnitude.

    3. Re:Infrared? by NatasRevol · · Score: 1

      Well, that will solve everything then!

      --
      There are two types of people in the world: Those who crave closure
    4. Re:Infrared? by Anonymous Coward · · Score: 0

      I guess these are the current speeds for infra red

      SIR: 9.6-115.2 kbit/s, asynchronous, RZI, UART-like, 3/16 pulse
      MIR: 0.576-1.152 Mbit/s, RZI, 1/4 pulse, HDLC bit stuffing
      FIR: 4 Mbit/s, 4PPM
      VFIR: 16 Mbit/s, NRZ, HHH(1,13)
      UFIR: 96 Mbit/s, NRZI, 8B10B
      GigaIR: 512 Mbit/s – 1Gbit/s, NRZI, 2-ASK, 4-ASK, 8B10B
      5/10GigaIR: seems to be a new IrPHY coming soon

    5. Re:Infrared? by NatasRevol · · Score: 1

      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.

      --
      There are two types of people in the world: Those who crave closure
    6. Re:Infrared? by Anonymous Coward · · Score: 0

      we all start wearing beanies with IR antennas on top of them

      That's brilliant! Just the thing for an Arduino Lilypad.

      I for one welcome our IR beanie wearing overlords.

    7. Re:Infrared? by Anonymous Coward · · Score: 0

      Palm Pilot?

      Pffft, we amateur radio operators were doing light communication decades ago (many decades in fact).

    8. Re:Infrared? by Lehk228 · · Score: 1

      gameboy color also had such a device. i think 2 games used it

      --
      Snowden and Manning are heroes.
  4. Ah So by Anonymous Coward · · Score: -1

    Ah yes, Chinaman build great big antenna, now he watch chick in short skirt get demon tentacle-fucked!

    1. Re:Ah So by Anonymous Coward · · Score: 0

      Ah yes, Chinaman build great big antenna, now he watch chick in short skirt get demon tentacle-fucked!

      Suspiciously white looking chick too. I forgot, why do anime characters look so non-asian? There was definitely some reason for that. And uh, what's with the tentacles anyway?

    2. Re:Ah So by cpicon92 · · Score: 4, Insightful

      Ah yes, Chinaman build great big antenna, now he watch chick in short skirt get demon tentacle-fucked!

      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.

    3. Re:Ah So by Anonymous Coward · · Score: 1

      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.

    4. Re:Ah So by firex726 · · Score: 2, Insightful

      Also, what's with all the racist jokes in this thread?
      Seems like an unusually high number compared to other stories involving Chinese people.

    5. Re:Ah So by Anonymous Coward · · Score: 0

      pornography is illegal in China,

      It's illegal in Japan as well. Hence tentacles, which don't technically meet the definition.

    6. Re:Ah So by Anonymous Coward · · Score: 0

      A tentacle is like a prehensile penis. A prehensile penis > non-prehensile penis.

    7. Re:Ah So by Anonymous Coward · · Score: 0

      Please do not give stupid comments the credability of the title "joke". It was not even funny

    8. Re:Ah So by cpicon92 · · Score: 1

      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

    9. Re:Ah So by Kremmy · · Score: 1

      The Western characters in anime tend to have a very different cut than the Asian characters that you say look non-Asian.

    10. Re:Ah So by Anonymous Coward · · Score: 0

      Much like porn being illegal for muslims and seal team 6 finding volumes of it at Bin Laden's hideout, it don't matter the age or religion, guys just want a beer and to see something naked.

    11. Re:Ah So by Anonymous Coward · · Score: 0

      Also, what's with all the racist jokes in this thread?
      Seems like an unusually high number compared to other stories involving Chinese people.

      Propaganda to soften-up Democratic and Republican consumers for war@China, as interest/belief in war@drugs and war@terra' lose focus/funding.

    12. Re:Ah So by Anonymous Coward · · Score: 0

      Japan outlaws pornography but their legal definition of such requires the display of genitals. Similarly, prostitution is illegal but the definition is sufficiently narrow to exclude many acts considered sex in other countries' laws. We're arguing semantics. The tentacle thing is certainly not without precedent but it was nurtured to its current significance by more recent laws.

    13. Re:Ah So by Palamos · · Score: 1

      Agreed. I think the subtext of the racism is the fear on the part of our american cousins that they are about to be usurped on the world's stage by our other cousins from China, it's a form of nervous laughter and also displays the atrociously poor reporting of non american news in the home country.

  5. But how... by TWX · · Score: 0

    ...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!

    --
    Do not look into laser with remaining eye.
  6. What's All The Fuss? by Anonymous Coward · · 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.

    1. Re:What's All The Fuss? by gl4ss · · Score: 1

      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.

      --
      world was created 5 seconds before this post as it is.
    2. Re:What's All The Fuss? by Anonymous Coward · · Score: 0

      I thought this hit its peak and fizzled out when somebody got the bright idea of rigging the office florescents as carriers.

      "Well, I saw how the office lights were always flickering, and wondered if we could put that to good use."
      -- Imaginary asshole who purposefully made the office lights flicker to get in the "news"

    3. Re:What's All The Fuss? by sl4shd0rk · · Score: 2

      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 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.

      --
      Join the Slashcott! Feb 10 thru Feb 17!
    4. Re:What's All The Fuss? by PlusFiveTroll · · Score: 1

      >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.

    5. Re:What's All The Fuss? by mlts · · Score: 1

      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" has some improvements with it, but fundamentally, this was done before.

      [1]: LocalTalk as in Apple's networking solution which was a different L1 media than Ethernet. Of course, there was LocalTalk as a protocol which helped confuse things even more.

    6. Re:What's All The Fuss? by Anonymous Coward · · Score: 0

      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.

      Capacitor? It's possible you're using a poorly (and inefficiently) designed system; one with a transformer without bridge rectifier or capacitor as it's power source. A transformer only supply will make LEDs flicker at line frequency with significantly less than 50% duty cycle. A Transformer/bridge/capacitor supply will make LEDs flicker at 2x line frequency and not by much. A switching power supply will make LEDs flicker at nx10^4 hz which will be imperceptable (but you must choose the power supply carefully to avoid a high pitched noise if that is a concern).

    7. Re:What's All The Fuss? by CanHasDIY · · Score: 1

      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.

      --
      An enigma, wrapped in a riddle, shrouded in bacon and cheese
    8. Re:What's All The Fuss? by Calinous · · Score: 1

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

    9. Re:What's All The Fuss? by AmiMoJo · · Score: 1

      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 there won't be more than a few percent of the total brightness, because to get high speeds you need to have very small changes in signal amplitude. The flicker you see in some crap bulbs is due to the 50/60Hz mains frequency or really shoddy switch mode power supplies.

      What needs to happen is for a low cost standard to be developed and made available in quality LED light bulbs.

      --
      const int one = 65536; (Silvermoon, Texture.cs)
      SJW, n: "Someone I don't like, and by the way I'm a fuckwit" - AC
    10. Re:What's All The Fuss? by Anonymous Coward · · Score: 0

      Light has the advantage of not travelling through walls.

      Too bad for most homes, it has the disadvantage of not travelling through walls. Though, I'm sure it would work great in the straw huts of Gilligan's Island.

    11. Re:What's All The Fuss? by Neil+Boekend · · Score: 1

      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.

      --
      Well, I might have a way, but it only works on a semi spherical planet in a vacuum.
    12. Re:What's All The Fuss? by CanHasDIY · · Score: 1

      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.

      --
      An enigma, wrapped in a riddle, shrouded in bacon and cheese
  7. Is it me? by lesincompetent · · Score: 0

    Never heard of RiFi.

    1. Re:Is it me? by Anonymous Coward · · Score: 0

      Never heard of RiFi.

      Get over your own stupid.

      I guarantee you that your Chinese is far worse than her English, and there will be sounds in Chinese (and several other languages) you can't quite make either.

      If you don't grow up using certain phonemes, it's almost impossible to get them right later in life.

    2. Re:Is it me? by lesincompetent · · Score: 1

      Butthurt much?!

  8. Do you work for the NSA? by Barnett · · Score: 0

    Sorry for asking...

  9. needs a science editor by Anonymous Coward · · Score: 0

    From the article, emphasis mine

    But Li-Fi isn't without its drawbacks. Because it is dependent on light, the technology can't penetrate walls or work in complete darkness.

    That seems.... unlikely.

    1. Re:needs a science editor by Anonymous Coward · · Score: 0

      When an air purifier is advertised to work in complete silence, it means that it doesn't cause noise, not that it requires silence to function. Same here.

    2. Re:needs a science editor by Anonymous Coward · · Score: 0

      When an air purifier is advertised to work in complete silence, it means that it doesn't cause noise, not that it requires silence to function. Same here.

      So, they have to use only visible light for this?

    3. Re:needs a science editor by tibit · · Score: 1

      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.

      --
      A successful API design takes a mixture of software design and pedagogy.
    4. Re:needs a science editor by Anonymous Coward · · Score: 0

      Yes, otherwise it isn't Li-Fi.

    5. Re:needs a science editor by unitron · · Score: 1

      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.

      --

      I see even classic Slashdot is now pretty much unusable on dial up anymore.

    6. Re:needs a science editor by Anonymous Coward · · Score: 0

      When an air cleaner is advertised to work in complete silence, it means it doesn't work.

  10. Si-fi by Mirar · · 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?

    1. Re:Si-fi by mlts · · Score: 1

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

    2. Re:Si-fi by Mirar · · Score: 1

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

    3. Re:Si-fi by unitron · · Score: 1

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

      Congratulations, you just wrote your new sig file.

      --

      I see even classic Slashdot is now pretty much unusable on dial up anymore.

  11. Didn't they do this in the War? by Anonymous Coward · · Score: 0

    Yes, they did: http://www.laud.no/ww2/lispr/lispr2.htm OK,so it was for voice, but surely data is data.

  12. What's wrong with Irda? by Anonymous Coward · · Score: 0

    I mean, that was pretty common technology (including chipsets etc) about a decade ago. I used it, for example, for getting dialup service for my Thinkpad laptop via a Siemens Si35 mobile phone while on the road (9600 baud is enough for Email exchange). Somewhat handier (though less reliable) than a serial cable.

  13. Great use of technology by Enry · · Score: 1

    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.

  14. RONJA by Anonymous Coward · · Score: 0

    How is this different fron RONJA that has been around quite a while?

    1. Re:RONJA by Anonymous Coward · · Score: 0

      yep.. looks like re-inventing the whe^h^h^h RONJA to me too, and that has been going since year 2004 at least (the wikipedia article has been created on october 2004).

      https://en.wikipedia.org/wiki/RONJA

      The official RONJA page, http://ronja.twibright.com/ shows a copyright of 1998-2013 and the early RONJA versions used an AUI network interface, so i think the year 1998 is when that project started.

  15. IrDA by Dan+East · · 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.

    --
    Better known as 318230.
    1. Re:IrDA by mlts · · Score: 1

      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 to have a physical connection to it.

    2. Re:IrDA by tibit · · Score: 1

      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.

      --
      A successful API design takes a mixture of software design and pedagogy.
    3. Re:IrDA by mlts · · Score: 1

      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.

    4. Re:IrDA by Anonymous Coward · · Score: -1

      Wait WTH did i miss something here Interchanging between pcmcia and CF last i checked both of those are based on ATA to some extent and adapters very much DO exist.

    5. Re:IrDA by evilviper · · Score: 1

      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 and print it out.

      Only a few could afford laptops, and they:

      1) Didn't carry them around much because of size/weight and expense. Being too big to carry every time someone got up (e.g. to grab a book), several got stolen.
      2) Took too long to pull out and start-up to use for quickly scribbling notes. Suspend/Hibernate didn't exist yet, and Standby was inconsistent and used lots of power.
      3) Were big, taking up most of a desk. And were distractingly noisy.
      4) Couldn't directly print on-campus. Instead had to find a PC without many restrictions on it, use a floppy (or e-mail) to copy the file over, and print from there.

      Cell phones are vastly more powerful than my old PDA, but phones don't have touch-type keyboards, battery life is poor, and direct IrDA printing is a thing of the past. WiFi printing might be an option these days, but it is far more complex to setup.

      --
      Slashdot gets worse every day... Pipedot: News for nerds, without the corporate slant
    6. Re:IrDA by Anonymous Coward · · Score: 0

      IrDA can also be used to control things that have an IR remote. This is the reasoning behind having IR on the S4, though I'm wondering whether the S4 has a receiver and emulates devices it sees, versus having a DB of devices with known patterns.

    7. Re:IrDA by Palamos · · Score: 1

      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.

  16. Now try lasers! by DdJ · · Score: 1

    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 photosensors, lined up the beams, and got the modems talking to each other.

    As I recall, they had a working 1200 baud connection from over a dozen blocks away. Didn't have any practical use, but it was kinda awesome.

    (I think I've still got a box of old helium neon laser tubes in my basement somewhere.)

    1. Re:Now try lasers! by Anonymous Coward · · Score: 0

      Actually, some electronics magazine went over several kilometers using big incandescent spotlights for transferring speech (should be good for 2400 bps I guess). Turns out that at shallow modulation depths, the filaments are quite more responsive than one would think.

    2. Re:Now try lasers! by tibit · · Score: 1

      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.

      --
      A successful API design takes a mixture of software design and pedagogy.
    3. Re:Now try lasers! by nurb432 · · Score: 1

      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 'universal tablet' devices that had no local storage, just pick up one and use it like a pad of paper. It used Infrared from transceivers in the ceiling.

      While its nice to see it making a comeback, I really don't see the big deal or the 'big and expensive' nonsense..

      --
      ---- Booth was a patriot ----
  17. Re:Race? Indeed by BoRegardless · · Score: 2

    Over 170 ethnic groups inhabit inside China's borders. The only race that controls China is the ultra wealthy Communist Party.

  18. Better Caul Saul! by Anonymous Coward · · Score: 0

    And you thought the epileptic seizure problems from video games were bad, wait until you start putting LI-FI emitters everywhere!

  19. Why not... by Anonymous Coward · · Score: 0

    ...use Fiber Optic lines?
    This "li-fi" technology has no place in a home if it costs a prohibitive cost ABOVE FiO and only goes 3 meters.
    Sheesh!

  20. 38-year-old technology, at least by Anonymous Coward · · Score: 0

    Light Beam Communications, copyright 1975, Forrest Mims, ISBN 978-0672211478 Howard W. Sams

    1. Re:38-year-old technology, at least by unitron · · Score: 1

      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.

      --

      I see even classic Slashdot is now pretty much unusable on dial up anymore.

  21. Data Transmission in Glass, in Air: All the same by BoRegardless · · Score: 1

    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.

  22. Re:Race? Indeed by mlts · · Score: 2

    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.

  23. Not news, nor discovery by Anonymous Coward · · Score: 0

    http://ronja.twibright.com

  24. Re:Data Transmission in Glass, in Air: All the sam by tibit · · Score: 1

    And let's not forget the clacks towers!

    --
    A successful API design takes a mixture of software design and pedagogy.
  25. oh by Anonymous Coward · · Score: 0

    took me a moment to realize that Li Fi was not the name of the professor...

  26. Meaningless comparisons FTW by wonkey_monkey · · 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.

    --
    systemd is Roko's Basilisk.
  27. Upstream by MancunianMaskMan · · Score: 1

    could anyone in the know enlighten us how the uplink is supposed to work? TFA doesn't clarify.

  28. "must be within three meters" by csumpi · · Score: 2, Informative
    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.

    1. Re:"must be within three meters" by Anonymous Coward · · Score: 0

      Does everything researched require an application? Sometimes stuff is just fun to research.

    2. Re:"must be within three meters" by evilviper · · Score: 1

      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.

      --
      Slashdot gets worse every day... Pipedot: News for nerds, without the corporate slant
    3. Re:"must be within three meters" by Anonymous Coward · · Score: 0

      Bluetooth works whether or not your lights are on. It even works in places where there are no lights at all.

  29. Re:Race? Indeed by godefroi · · Score: 1

    Historically, Persians were Zoroastrian, not Muslim, right?

    --
    Karma: Poor (Mostly affected by lame karma-joke sigs)
  30. Re:Data Transmission in Glass, in Air: All the sam by LeadSongDog · · Score: 1

    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 lots of access points that look like ordinary LED "bulbs"... Oh shit, THAT's why those things are made in China, they've gotten us to bug our own houses!

    --
    Oh, I'm sorry sir, I thought you were referring to me, Mr. Wensleydale.
  31. Yes, it's freespace... by Anonymous Coward · · Score: 0

    ...and it's been around for a while. Some background at Tikalon Blog.

  32. Lichtsprechgerät --- 'light' speaker appr by Anonymous Coward · · Score: 0

            http://www.laud.no/ww2/lispr/

            Been done for years.... nicht war?

  33. 1990 called by deadweight · · Score: 1

    WTF? My early 1990s era laptops had this. How is this NEW?

    1. Re:1990 called by Anonymous Coward · · Score: 0

      Did you ever try using it? It only works across a few inches of gap.

    2. Re:1990 called by deadweight · · Score: 1

      We had an IR system one place I worked with "IR balls" up above the cubes. Seemed to work over that gap OK.

  34. Re:Data Transmission in Glass, in Air: All the sam by Anonymous Coward · · Score: 0

    You are absolutely correct. All we need is a hub of fiber ends taped together instead of GBICs and switching. Broadcom has been making a killing on port costs for years for nothing...

  35. Re:Race? Indeed by Arker · · Score: 1

    Historically, no one was Muslim before approximately 600ad. So if that's your test then Arabs fail it just the same as Persians.

    --
    =-=-=-=-=-=-=-=-=-=-=-=-=-=-
    Friends don't let friends enable ecmascript.
  36. mod parent up by frovingslosh · · Score: -1, Troll

    Even though it was an AC, the parent here was actually funny and should have been modded up. I'm amazed that the modder had nothing better to do with his mod points than mod this down in a mistaken display of Poritical collectness.

    What everyone seems to be missing here is this fantastic accomplishment. What the starving Chinese should take grate pride in is there is no little trinket that Chi Nan can fail to duplicate, as long as she doesn't have to pay for it herself.

    --
    I'm an American. I love this country and the freedoms that we used to have.
    1. Re:mod parent up by ShanghaiBill · · Score: 2

      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. There are more middle class people in China than in America.

    2. Re:mod parent up by JeffAtl · · Score: 1

      There are more middle class people in China than in America.

      With a population about 4 times greater, I'd hope so.

    3. Re:mod parent up by The+Mighty+Buzzard · · Score: 2

      The Chinese are not starving. This is 2013, not 1961. 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.

      --
      Violence is like duct tape. If it doesn't solve the problem, you didn't use enough.
    4. Re:mod parent up by Antonovich · · Score: 1

      The other way round might have worked actually - there are large parts of at least the south east of China (like Fujian) that pronounce both "r" and "l" the same as "l"(meaning there is no phonetic difference).

    5. Re:mod parent up by Anonymous Coward · · Score: 0

      Man, all my best shit gets censored...

    6. Re: mod parent up by gzuckier · · Score: 1

      As I've seen it explained, China is a country pretty similar to the US; plus a couple of billion subsistence farmers.

      --
      Star Trek transporters are just 3d printers.
    7. Re:mod parent up by nobodie · · Score: 1

      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.
      But, I should add that the Chinese /r/ is remarkably different from the western European /r/

      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 they have more poor people in China than the entire population of the US. It's a matter of scale. You have to look in terms of proportion to say anything of value.

      --
      Subversion of spatial scale luxury decoration ideas.
  37. Its been done before for less by randomErr · · Score: 1

    Its been done before for less

    Microprocessor
    http://www.linux-cae.net/Projects/Serial/Laser/laser.htm

    Aurdio Laser Modem:
    http://makezine.com/2008/08/13/laser-modem-with-an-ardui/

    Raspberry Pi
    http://www.ohmpie.com/lasermodemvideo/

    --
    You say things that offend me and I can deal with it. Can you?
  38. you missed the point by frovingslosh · · Score: 1

    Sure, but your 1990's laptop didn't manage to accomplish it by spending $500,000 of someone else's money.

    --
    I'm an American. I love this country and the freedoms that we used to have.
  39. Really? by Anonymous Coward · · Score: 0

    Unlike traditional Wi-Fi routers that use radio signals, Chi's system relies on light to send and receive data wirelessly.

    ::FACEPALM::

  40. Features so awesome it was REMOVED from laptops by BitZtream · · 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.

    --
    Persistent Volume manager for Kubernetes - https://github.com/dwimsey/openshift-pvmanager
  41. Line of sight? by loshwomp · · 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.

  42. Betcha it works through water.... by anubi · · Score: 1

    My take is if she may well patent it as an UNDERWATER communication medium.

    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.

    --
    "Prove all things; hold fast that which is good." [KJV: I Thessalonians 5:21]