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Chinese Professor Builds Li-Fi System With Retail Parts

timothy posted about 9 months ago | from the shine-on-crazy-diamond dept.

Networking 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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SO REALLY IT IS RI-FI ?? (-1)

Anonymous Coward | about 9 months ago | (#45335143)

You know being Chinese and all !!

does it work through walls? (-1, Flamebait)

alen (225700) | about 9 months ago | (#45335145)

i only ask because homes in the USA have them

Re:does it work through walls? (-1)

Anonymous Coward | about 9 months ago | (#45335175)

i only ask because homes in the USA have them

Yeah unlike those dumb Chinese huh? You're racist

Re:does it work through walls? (-1, Troll)

Anonymous Coward | about 9 months ago | (#45335371)

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

Re:does it work through walls? (1)

MightyYar (622222) | about 9 months ago | (#45335385)

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.

Re:does it work through walls? (1)

Fallso (2997549) | about 9 months ago | (#45335627)

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 (2)

BoRegardless (721219) | about 9 months ago | (#45335679)

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

Re:Race? Indeed (2)

mlts (1038732) | about 9 months ago | (#45335775)

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.

Re:Race? Indeed (1)

godefroi (52421) | about 9 months ago | (#45336049)

Historically, Persians were Zoroastrian, not Muslim, right?

Re:does it work through walls? (1)

sexconker (1179573) | about 9 months ago | (#45336571)

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? (-1)

Anonymous Coward | about 9 months ago | (#45335937)

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.

Re:does it work through walls? (1)

Anonymous Coward | about 9 months ago | (#45335181)

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

Re: does it work through walls? (4, Informative)

DigiShaman (671371) | about 9 months ago | (#45335457)

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).

Re: does it work through walls? (1)

KiloByte (825081) | about 9 months ago | (#45335523)

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

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

Re: does it work through walls? (0)

Anonymous Coward | about 9 months ago | (#45335595)

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.

Re: does it work through walls? (0)

Anonymous Coward | about 9 months ago | (#45336583)

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.

Re: does it work through walls? (0)

Anonymous Coward | about 9 months ago | (#45335735)

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.

Re: does it work through walls? (0)

Anonymous Coward | about 9 months ago | (#45335853)

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

Re: does it work through walls? (2)

Concerned Onlooker (473481) | about 9 months ago | (#45336173)

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

Man, that's one powerful ssh client.

Re: does it work through walls? (1)

IndustrialComplex (975015) | about 9 months ago | (#45336309)

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? (4, Interesting)

TWX (665546) | about 9 months ago | (#45335187)

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.

Re:does it work through walls? (1)

SJHillman (1966756) | about 9 months ago | (#45335275)

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

Re:does it work through walls? (4, Interesting)

Lumpy (12016) | about 9 months ago | (#45335339)

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.

Re:does it work through walls? (0)

Anonymous Coward | about 9 months ago | (#45335399)

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.

Re:does it work through walls? (1)

TWX (665546) | about 9 months ago | (#45335429)

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.

Re:does it work through walls? (0)

Anonymous Coward | about 9 months ago | (#45335927)

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.

Re:does it work through walls? (0)

Anonymous Coward | about 9 months ago | (#45336119)

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.

Re:does it work through walls? (1)

jiriw (444695) | about 9 months ago | (#45335441)

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.

Re:does it work through walls? (1)

RabidReindeer (2625839) | about 9 months ago | (#45336047)

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!

Re:does it work through walls? (0)

sg_oneill (159032) | about 9 months ago | (#45335197)

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.

Re:does it work through walls? (0)

dreamchaser (49529) | about 9 months ago | (#45335221)

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

Re: does it work through walls? (0)

Anonymous Coward | about 9 months ago | (#45335357)

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

Do you work for the NSA? (0)

Barnett (550375) | about 9 months ago | (#45335227)

Sorry for asking...

Re:does it work through walls? (-1)

Anonymous Coward | about 9 months ago | (#45335345)

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.

Re:does it work through walls? (1)

tlhIngan (30335) | about 9 months ago | (#45336491)

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.

Infrared? (1)

Anonymous Coward | about 9 months ago | (#45335147)

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

Re:Infrared? (1)

NatasRevol (731260) | about 9 months ago | (#45335427)

Yeah, at 400 baud.

Re:Infrared? (0)

Anonymous Coward | about 9 months ago | (#45335623)

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

Re:Infrared? (1)

NatasRevol (731260) | about 9 months ago | (#45335659)

Well, that will solve everything then!

Re:Infrared? (0)

Anonymous Coward | about 9 months ago | (#45335669)

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

Re:Infrared? (1)

NatasRevol (731260) | about 9 months ago | (#45335709)

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.

Re:Infrared? (0)

Anonymous Coward | about 9 months ago | (#45336161)

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.

Ah So (-1)

Anonymous Coward | about 9 months ago | (#45335149)

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

Re:Ah So (0)

Anonymous Coward | about 9 months ago | (#45335211)

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?

Re:Ah So (0)

Anonymous Coward | about 9 months ago | (#45335759)

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

Re:Ah So (1)

Kremmy (793693) | about 9 months ago | (#45336207)

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

Re:Ah So (4, Insightful)

cpicon92 (1157705) | about 9 months ago | (#45335263)

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.

Re:Ah So (1)

Anonymous Coward | about 9 months ago | (#45335485)

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.

Re:Ah So (0)

Anonymous Coward | about 9 months ago | (#45336589)

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.

Re:Ah So (2, Insightful)

firex726 (1188453) | about 9 months ago | (#45335521)

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

Re:Ah So (0)

Anonymous Coward | about 9 months ago | (#45335769)

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

Re:Ah So (0)

Anonymous Coward | about 9 months ago | (#45335671)

pornography is illegal in China,

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

Re:Ah So (1)

cpicon92 (1157705) | about 9 months ago | (#45335867)

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]

But how... (0)

TWX (665546) | about 9 months ago | (#45335163)

...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!

What's All The Fuss? (5, Insightful)

Anonymous Coward | about 9 months ago | (#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.

Re:What's All The Fuss? (1)

gl4ss (559668) | about 9 months ago | (#45335233)

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.

Re:What's All The Fuss? (0)

Anonymous Coward | about 9 months ago | (#45335389)

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"

Re:What's All The Fuss? (2)

sl4shd0rk (755837) | about 9 months ago | (#45335433)

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.

Re:What's All The Fuss? (1)

Calinous (985536) | about 9 months ago | (#45336209)

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

Re:What's All The Fuss? (1)

PlusFiveTroll (754249) | about 9 months ago | (#45335619)

>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.

Re:What's All The Fuss? (1)

mlts (1038732) | about 9 months ago | (#45335637)

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.

Re:What's All The Fuss? (0)

Anonymous Coward | about 9 months ago | (#45336053)

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).

Yes, it's freespace... (0)

Anonymous Coward | about 9 months ago | (#45336143)

...and it's been around for a while. Some background at Tikalon Blog [tikalon.com] .

Re:What's All The Fuss? (1)

CanHasDIY (1672858) | about 9 months ago | (#45336191)

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.

Is it me? (0)

lesincompetent (2836253) | about 9 months ago | (#45335195)

Never heard of RiFi.

Re:Is it me? (0)

Anonymous Coward | about 9 months ago | (#45335337)

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.

Re:Is it me? (1)

lesincompetent (2836253) | about 9 months ago | (#45336637)

Butthurt much?!

needs a science editor (0)

Anonymous Coward | about 9 months ago | (#45335277)

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.

Re:needs a science editor (0)

Anonymous Coward | about 9 months ago | (#45335379)

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.

Re:needs a science editor (0)

Anonymous Coward | about 9 months ago | (#45335435)

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?

Re:needs a science editor (0)

Anonymous Coward | about 9 months ago | (#45336435)

Yes, otherwise it isn't Li-Fi.

Re:needs a science editor (1)

tibit (1762298) | about 9 months ago | (#45335779)

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.

Si-fi (1)

Mirar (264502) | about 9 months ago | (#45335291)

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?

Re:Si-fi (1)

mlts (1038732) | about 9 months ago | (#45335699)

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

Re:Si-fi (1)

Mirar (264502) | about 9 months ago | (#45335861)

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

Didn't they do this in the War? (0)

Anonymous Coward | about 9 months ago | (#45335293)

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

What's wrong with Irda? (0)

Anonymous Coward | about 9 months ago | (#45335297)

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.

Great use of technology (1)

Enry (630) | about 9 months ago | (#45335325)

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.

RONJA (0)

Anonymous Coward | about 9 months ago | (#45335335)

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

Re:RONJA (0)

Anonymous Coward | about 9 months ago | (#45335649)

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.

IrDA (5, Interesting)

Dan East (318230) | about 9 months ago | (#45335347)

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.

Re:IrDA (1)

mlts (1038732) | about 9 months ago | (#45335733)

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.

Re:IrDA (1)

tibit (1762298) | about 9 months ago | (#45335803)

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.

Re:IrDA (1)

mlts (1038732) | about 9 months ago | (#45336465)

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.

Now try lasers! (1)

DdJ (10790) | about 9 months ago | (#45335381)

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.)

Re:Now try lasers! (0)

Anonymous Coward | about 9 months ago | (#45335495)

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.

Re:Now try lasers! (1)

tibit (1762298) | about 9 months ago | (#45335829)

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.

Better Caul Saul! (0)

Anonymous Coward | about 9 months ago | (#45335701)

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

Why not... (0)

Anonymous Coward | about 9 months ago | (#45335711)

...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!

38-year-old technology, at least (0)

Anonymous Coward | about 9 months ago | (#45335739)

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

Data Transmission in Glass, in Air: All the same (1)

BoRegardless (721219) | about 9 months ago | (#45335753)

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.

Re:Data Transmission in Glass, in Air: All the sam (1)

tibit (1762298) | about 9 months ago | (#45335847)

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

Re:Data Transmission in Glass, in Air: All the sam (1)

LeadSongDog (1120683) | about 9 months ago | (#45336097)

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!

Not news, nor discovery (0)

Anonymous Coward | about 9 months ago | (#45335837)

http://ronja.twibright.com

oh (0)

Anonymous Coward | about 9 months ago | (#45335883)

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

Meaningless comparisons FTW (5, Insightful)

wonkey_monkey (2592601) | about 9 months ago | (#45335897)

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 (1)

MancunianMaskMan (701642) | about 9 months ago | (#45335991)

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

"must be within three meters" (2, Informative)

csumpi (2258986) | about 9 months ago | (#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.

Lichtsprechgerät --- 'light' speaker appr (0)

Anonymous Coward | about 9 months ago | (#45336181)

        http://www.laud.no/ww2/lispr/

        Been done for years.... nicht war?

1990 called (1)

deadweight (681827) | about 9 months ago | (#45336509)

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