back to article Wireless-data LED lamps to replace lightbulbs - US profs

The US government is funding research into using LED lighting as data network access points. Room or street lamps would link with devices using visible light, carrying data beyond over existing power lines. "This is a unique opportunity to create a transcendent technology that not only enables energy-efficient lighting, but …


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  1. Rosco

    Best. Name. Ever

    I want to be called 'Inder Monga'

  2. Anonymous Coward
    Anonymous Coward

    What about those of us sensitive to flicker?

    Here I was thinking LEDs would be a perfect energy efficient solution, low usage and no flicker, now as usual some muppet decides that people wont be able to see it (I can discern flicker even on 100hz plus CRT screens (why I went to TFT) and now they want to irritate people with flickering lightbulbs.....remind me again whats wrong with wireless? oh yeah the claims of "cancer" which is a genetic flaw rather than a to love the dumbing down of everything

  3. Steven


    as long as everyone only uses the internet at night...

  4. JohnP
    Thumb Down

    switch off

    so you can break the data network by the simple act of switching off a light!

  5. Dominic Kua
    Paris Hilton

    I can see it as broadcasting

    But how do you send thing upstream with this? Fall back on good old wifi and lose the directionality and security they're pushing?

  6. Peter Ford
    Thumb Down

    One way?

    So how do these smart lights receive the data I want to transmit from my (for example) laptop?

    Do I have to have a 20W LED flashing away on to top of my device so the receiver can pick it out from (say) passing car headlights?

  7. CeeJay

    "not unlike IrDA kit "

    Hope that's not really a valid comparison. Because if so, it'll suck mercilessly.

  8. Wize

    Flickering lights is a bad idea

    I can feel a headache already.

    You'll also be stuffed if you want to pick up a signal in a second floor flat (like many students) as you'll be on the wrong side of the bulb.

  9. D@v3

    nice idea

    but what about when you 'want' to have access to your wireless network outside, ie. out of the range of cables. Would you have to have some sort of 'light post' connected by power line to the rest of your house, which would no doubt be susceptible to some kind of interferance from the Sun (large nuclear light source, not tabloid comic strip)

  10. Anonymous Coward
    Anonymous Coward


    How does this work during the daytime? Will I have to close the curtains to surf the web (even when it isn't pr0n)?

  11. Vincent
    Thumb Down

    Increased security is all fine and well...

    Increased security is all fine and well, but what's the point in using wireless if you can only use it in one room? You might as well just use an Ethernet cable and be done with it.

  12. Eddie Edwards

    Calm down

    "now as usual some muppet decides that people wont be able to see it (I can discern flicker even on 100hz plus CRT screens (why I went to TFT) and now they want to irritate people with flickering lightbulbs"

    To transmit useful amounts of data the LEDs will need to flicker at more than 100,000Hz. You can't discern that.

    In fact many LEDs flicker; it's called Pulse-Width Modulation and it's used to dim them. Generally this occurs at over 1kHz and is also impossible to discern. Look at the pulsing LED on a Mac when it's asleep. Do you see flicker?

  13. Anonymous Coward
    Anonymous Coward

    Didn't we get rid of IrDA for a reason?

    Oh yeah, it's slow and pretty useless.

    And what's this about it being secure? I can't see unsecured WiFi access points from across the river, but I CAN see streetlights. So unless they're having some serious encryption, it's not exactly "secure" or even "secure-ish".

    I really can't see what this can do that WiFi/Bluetooth can't do better EXCEPT provide woefully slow, Line-Of-Sight internet connections. And people who want those can either use a unidirectional WiFi or other microwave link or a laser link.

    Maybe it could be used in lighthouses? Broadcast their actual position so that ultra-cheapo DGPS (DGPS "light" if you will...) style systems can be created around coastal areas. Or used in cars to pass automated messages between each other?

  14. Nigel


    You can see flicker at 50Hz and possibly at a few hundred. You certainly can't at the hundred megahertz or so you'd need for wireless optical networking.

    I also doubt that it's possible. White LEDs use a phosphor to convert blue, violet or ultraviolet light from the LED into visible light. Those phosphors stay glowing for many microseconds after the illumination ceases, so you could not modulate them at 100MHz. Maybe there's enough leakage of raw LED light to carry a signal., but that still leaves the problem of how your computer, phone, whatever is going to signal back!

  15. Cameron Colley

    More secure, are you sure?

    This may be more secure if you're sitting in a windowless room -- but if the light can be seen from a window then a decent telescope could pick it out from miles away.

  16. John Chadwick

    Yeah but...

    What use is a data transfer mechanism that only works when:

    a) The lights are on.

    b) The lights are the brightest available light source.

    And what happens when:

    a) There's a mirror or two in the room.

    b) The LED's begin to fail.

    I look forward to the results of this research with interest, I can't see this kind of light bulb being cheap. I use LED lighting at home and it does flicker. Oh and light does bend round corners, and reflect off all sorts of things.

  17. Anonymous Coward
    Anonymous Coward

    This story got me thinking

    Of the lyrics of a dance music track and I put some more appropriate words to it.

    Here we go

    "I wear my sunglasses at night, so I can, so I can, catch streaming data in my eyes"

  18. Anonymous Coward
    Black Helicopters


    Bad for laptops.

    Good for a national (people) monitoring network. You could monitor all sort of things...

    The speed of traffic, or a specific car. Traffic patterns, or location/patterns of a specific car or device.

    If the light sources overlap, maybe you could count the number of people or objects under the light. Then track the movement of these objects from one light source to another.

    This sounds like revolutionary tech. I wonder what kind of light bulbs they are using in Iraq?

  19. Richard

    Inevitable Disc World reference

    So Finally someone wants to create...

    " The Light WANtastic..."

    Sounds like More Pork than Anything...

    Mines the one with the stars and sequins falling off......

  20. Anomalous Cowherd Silver badge

    Dance track?

    It's Corey Heart you heathen, from 1983. Kids these days.

  21. Steve
    Thumb Down

    what's that?

    Network connection disconnected, "hey, don't stand there, you're casting a shadow".

    The whole point of wireless is that it's not LoS, LoS sucks unless you're using a remote control on a tv (where your eyes need LoS as well).

  22. M7S

    They havent't thought of .....

    if you fit a receiver to news produced cars, the LED warning lamps now being fitted to emergency vehicles coud over-ride your stereo to say "Get out of the way". Nicely, or not. The ones on recovery/council trucks could say "beware possible hazard" In the first case it saves the futility of blasting the siren at those who cant hear above the bass that causes their car to vibrate excessively.

    There's bound to be a photosensitive epileptic who goes off at the same time this goes on. It may not be cause and effect but the resulting legal action will instill doubt in many regardless of the facts.

    The paranoid will claim it can be used as a form of mind control. Given that you cant really wear tinfoil visors, they're going to want some really good (welders?) glasses.

  23. Anonymous Coward
    Thumb Down

    secure, really?

    I'm sorry, I fail to see how this will actually be secure. It sounds as though they are throwing around the word 'secure', when we all know its not going to bed.

    I may need to invest in electrical tape as I'm not keen on wondering around and having my devices passively tracked by this ubiquitous network...

  24. Anonymous Coward
    Anonymous Coward

    We're not seeing the whole story, but...

    Unlike some of the posters above I'm bright enough to realise that the story is not giving us all the details of how this will work. Do these eejits really think that somebody developing a new technology is going to give away all their secrets in a story on El Reg? However...

    I'd be interested to know how they expect this to work in bright daylight.

    I'd also be interested to know how this "line of sight" techology is inherently more secure than say 802.11a. I have worked on my 11a network so that there is little or no leakage to the outside world except where there are windows. Positioning of the APs and devices and tuning of power output means 11a can be tuned to give very little leakage, but signals will still get out of windows. Now using your ambient lighting as a carrier will mean that anybody who can see your window can see your signal. Not only that but they will probably be able to pick it up from further away than they could with current technology. As an aside to this I just love the fact that 11n is being sold to home users on the strength of it's improved range. Nobody is telling Joe Public that if he can see his wireless network from further away then so can everybody else.

    My main concern, however, is the idea that light driven networks will intefere with each other less than current tech. Sounds good when you consider the line of site issue, which would be fine for the like of home networks. What happens where these networks operate within line of site of each other? Outside spaces? Large interior spaces like shoppin malls? Accessing your connection from your garden while your neighbour does the same? Your signal will be messed up for sure. Are they suggesting that we all use slightly different frequencies of light in order to avoid this issue?

    I'm not pooh poohing the tech until I see it demonstrated, however I will be very interested to see how they get round these and other issues.

  25. Ed Blackshaw Silver badge


    "As visible light doesn't penetrate walls or travel round corners, the developers say that the system would be more secure than present-day WiFi"

    Light doesn't travel round corners, but it does reflect off things quite well - after all it is our primary way of interacting with the world around us. Light also does not travel through walls, but windows don't seem to provide much of an issue.

    I would have thought that monochromatic light sources, such as those produced by LEDs would actually make these problems worse, as unlike radio-frequency waves, coherence of the reflected light would probably remain high for quite some distance, as long as an observer has a sensitive enough way of picking up the photons. Like any freely-available commercial CCD for instance...

  26. Ondrej Doubek

    re: "I wear my sunglasses at night..."

    I know another song, this time from Nazareth: "Dreeam Oon, it's so hard to see, the data You stream to me..."

    Just some 'romatic' thoughts:

    When working I rely on the light my screen is emitting, using some additional, low ambient light to save my eyes. I HATE white light, it is unatural and makes me uncomfortable (and I am not alone on that). That is why I don't use any energy saving lamps, LEDs, etc. I use a s good as no other light sources other than 40W warm toned glow bulbs- or candles- except for places like above kitchen sink or in the bathroom. I offset this pretentious use of inefficient lamps with using them really only where and when needed.

    And in any household I have been so far people prefer dimmed, warm toned light to stadium floodlights.

    Even in offices light designed to enhance wellbeing is becoming more and more popular. Less LUX of 'good quality light' are actually more ergonomic than abundant LUX of 'poor quality light' like white (actually green or blue) neon tubes.

    I don't believe that LEDs will ever become popular as a source of ambient light. Which means the whole idea of wireless-light@home or in the office is DOA.

    Leaves us only the streetlights. Well, it actually might work in public places. If I feel the need to browse the web while walking down the street or waiting for the bus, that is.


    The glasses because a tinfoil hat won't be enough anymore...

  27. Anonymous Coward

    Oh where to begin??

    Possibly the daftest idea in the world for many reasons tho.

    1) Line of Sight disappears

    2) Sooooo much interference from surrounding lights

    3) As rightly pointed, it sounds very similar to irda - brilliant

    4) Flickering at high frequencies doesn't mean it won't affect humans - think about sampling rates, and also the weird effects you see when looking at a helicopter rotor. Two people would not see the exact same effect

    5) Why is "light" thought of as different to normal wireless signals? It's just in a different frequency - the only real worry is high energy

    6) "Mirrors" a new problem - they're not, they cause problems with any signal - in fact any surface will cause the same issue depending on how dark it is. See MIMO for how it can be used to your advantage!

    Can we rename this "Morse Code 2.0" please?

  28. Anonymous Coward
    Anonymous Coward

    We're not seeing the whole story, but...

    Of the prok barrelling, there's no doubt.

  29. Anonymous Coward

    Epileptics Rejoice!

    This means I can now surf p0rn and set off break dancers at the same time! :)

  30. Anonymous Coward


    Surely this will only work when the LED bulbs are switched on? I don't know about fat lazy energy guzzling Yanks but I tend not to put my lights on during the day, when there is enough daylight to see by...

    I'm guessing the improved efficiency of the LEDs might be offset (at least partially) but having to switch on a bulb or 2 every time you need to connect to the internet.

  31. Anonymous Coward


    Is not an inherent property of the transmission medium. It is effected, or not, by the protocols being used.

    The human component(s) in any.end-to-end interface is/are always the weakest security link(s).

  32. Tim Schomer

    Does this mean...

    ... that they will finally start to fit new homes with a low voltage ring main? Does anyone know what standards they'll be using? (are there any standards yet??)

    Seems like a VERY good idea (easy to separate subnets by room etc..) and pretty secure, how will the PC transmit the data back to the network though? (lots of questions to be answered)

    Imagine you're whole home running on 12V - make it easy for battery backup.

  33. Anonymous Coward
    Black Helicopters


    Ican"t beleive youa re usinh the internet without wering tinfoilk sunglases. I have been using themfor years to advoid goberment mind conttrol.

  34. Anthony
    Thumb Down


    What a stupid idea.

    Epileptics won't even be able to be even out at night because of some stupid idea. Just give the lightsockets integrated wireless<>powerline converters and you'll not have to throw away expensive electronics whenever a lightbulb goes out.

  35. Charles Silver badge

    @Anonymous Coward

    Then how do you find your way around the community without need of a stick or a seeing-eye? Little problem with tinfoil is that it's *opaque*, so it's a little hard to see where one is going with them on.

    But back to the LED networking technology, I would imagine the bandwidth capability is a lot higher than IrDA. I believe the first intention of the technology is for home or office cubicle applications, particularly those with lights on all the time. As for the reverse trip, I would imagine a receptor can be placed into the base of the bulb to pick up and transmissions made by the computer.

  36. druck


    "if you fit a receiver to news produced cars, the LED warning lamps now being fitted to emergency vehicles coud over-ride your stereo to say "Get out of the way". Nicely, or not."

    If you haven't seen the flashing lights and heard the sirens over your stereo, you shouldn't be out on the road.

  37. GrahamT

    The lack of common knowledge is pitiful

    Epileptic fits are triggered by flashing strobe lights of a few hertz, not several thousand/million. When was the last time a seizure was triggered by a light bullb (100/120Hz flicker on 50/60 Hz mains) or even a TV (25/30 Hz interline, 50/60Hz interframe) or cinema (24/48 Hz)

    Secondly, 12Volt mains: someone has not studied Ohms law. For a given power current is inversely proportional to voltage. Reduce voltage from 240 -> 12, i.e divide by 20, and you multiply the current by 20, so instead of 13 amps flowing to your 3Kw appliance, you now have 260 amps. The mains wiring would be like 1/2 inch copper rods per conductor. (think car battery connections) As heat loss in the cable is proportional to the square of the current, then the heat would be 400 times what it is now for a given cable. That is why we move electricity around at high voltages then transform it down at the point of use if we need lower voltages or higher currents.

    If you want a practical example, compare the huge low voltage third rail of the Underground and the - higher powered - thin overhead high voltage line of mainline electrified railways.

  38. joe K
    IT Angle

    Come on techies!

    @Ondrej Oubek "I don't believe that LEDs will ever become popular as a source of ambient light. Which means the whole idea of wireless-light@home or in the office is DOA" - Well, domestic LED lighting will be delivered sooner than you think, within the next five years at the very most. Its quite a topical reason in the scientific and R&D communities for a reason.

    @AC "Sooooo much interference from surrounding lights" -Have a look at the solar spectrum, its all about where you select your communication wavelength. I could say the same thing about radio coomunications, even they suffer from interference from neighbouring devices and space.

    @Nigel "I also doubt that it's possible. White LEDs use a phosphor to convert blue, violet or ultraviolet light from the LED into visible light. Those phosphors stay glowing for many microseconds after the illumination ceases, so you could not modulate them at 100MHz" - Semiconductor engineering combined with nanotechnology means devices can be fabricated that emit at a precise wavelength, with a very short lag between electrical stimulation and photon emission. Look up quantum dots as a sample, phosphors are previous century technology.

    @Peter Ford "So how do these smart lights receive the data I want to transmit from my (for example) laptop?" - There are plenty of applications whose major requirement is for a downlink. You could use the technology for TV broadcasts, freeing up valuable spectrum.

    @Cameron Colley "This may be more secure if you're sitting in a windowless room -- but if the light can be seen from a window then a decent telescope could pick it out from miles away."- If the wavelengths and pulse shapes are chosen correctly, the signals will be far too degraded to recover an useful information following refraction/reflection through optical materials like glass. Also, having filtering optical signals can be done so much easier than with radio due to the higher frequencies and consequent required filter characteristics. Think red goggles, or IR absorbing quartz.

    It is an $18m dollar project, and consequently will have been peer reviewed extensively to make sure it is a viable project. Trust the scientists to do their job and develop the technology, and what you should all be debating is its applications. When Marconi, Tesla and co. pioneered radio technology they were laughed at. Who's laughing now? ( Fine, they're dead, and so aren't laughing at the moment but you get my point!)

  39. Anonymous Coward
    Anonymous Coward

    White Light?!

    Andrej: "I HATE white light, it is unatural and makes me uncomfortable "

    Assuming you are measuring the white balance by colour temperature what do you consider to be "white" and what do you consider to be "natural"?

    I ask because natural ambient light can only really be considered to be sunlight. Direct midday sunlight generally has a temerature of about 5-6000K. Truly natural daylight would generally include a degree of skylight and is generally considered to be 6500K. Shade in summer tends towards 7-8000K.

    Domestic tungsten lighting is around 2600-3000K.

    So natural light (daylight!) is considerably whiter than domestic lighting. So how can you consider white light unnatural? Do tell. I would be genuinely interested to know.

  40. M7S


    I agree, but they keep getting out there. I drive emergency vehicles. I know.

    Its just an idea similar to the original "Code 3" sf story from many years back.

    Also sirens are generally no good at motorway speeds, but an internal speaker to draw the drivers attention (if any) to their mirror (if any) might be good, especially for shifting traffic out of the way in columns instead of one at a time as each can only see behind them and then generally only see me when the last car behind them has moved aside.

  41. kventin
    Paris Hilton

    blast from the past?

    data: tick

    lamps: tick

    wifi: kind of

    as hot as back in 2004:

    (Ms. Hilton, because she looks as if she has forgotten something. (where is The Forgetting Vulture(TM) icon when you need it?))

  42. Frumious Bandersnatch Silver badge

    @epileptic commenters

    I believe it was The Andromeda Strain which featured a plot twist like this. Come to think of it, Jodie Foster's character in Contact also had a knack for spotting patterns in TV snow. I wonder what she'd make of this?

  43. Anonymous Coward
    Anonymous Coward

    Does anybody read the articles ?

    *Devices equipped with visible-light ports not unlike IrDA kit* would have a data connection whenever such a lamp was in line of sight.

    The data would be transmitted by the same LEDs which provided white-light illumination, flickering like tremendously fast signal lamps. *The data flicker would be imperceptible to humans.*

    As visible light doesn't penetrate walls or travel round corners, the developers say that the system would be more secure than present-day WiFi, and would avoid the problem of multiple radio networks competing for bandwidth. Furthermore, the much higher frequency of visible light compared to radio waves would mean there was much more wireless bandwidth to use.

    Nothing there is improbable or unusable. The people moaning about the flashing are wrong, the people moaning about not having line of sight upstairs are wrong (you have lights upstairs don't you ?), the people moaning about "how to upload" are wrong, the people talking about street lights are wrong (can you see an LED in the daylight, I can.).

    So just read the article, and it all becomes clear. This WILL make the net ubiquitous.

    Whether that's a good thing is better left for another time.

  44. E
    Thumb Down


    Acronym is 'SMERC'!

    What were they thinking?

    Not as bad as 'SLORC" though.

  45. Anonymous Coward


    "Can we rename this "Morse Code 2.0" please?"

    Call it "clacks" instead!

  46. Anonymous Coward
    Anonymous Coward


    Can you see an LED in daylight? Well yes, if it's powerful enough. The sensors will have a much even harder time since they are presumably working on a trigger switching between light and dark. If the ambient light is high enough they will have a very hard time "seeing" the dark bits.

    One issue with it being line of site is where you put the sensor/LED unit on the client. If the sensor is on the side of the computer facing away from your LED "access point" then it might just pick up the signal, but how powerful would the client LED need to be for the AP to pick up the signal from the client. Especially if the client LED is facing towards a window in bright sunlight or perhaps a dark surface. Will we all have to redecorate our houses in light colours?

    And there remains the issue of having different "APs" visible from the client location. Do you have different light frequencies for different APs? Otherwise how would you differentiate between on and off between the two or more APs you could see?

    None of these are necessarilly show stoppers, but it will be interesting to see how the developers plan to overcome them.

    Doesn't anybody read the articles? Yes they do, but they don't blindly believe everything they read.

  47. Britt Johnston

    1 password per lightbulb - valid 60 days

    A signal converter needs embedding in every light. (The signal must come from somewhere: a wifi router linked to the house mains? Perhaps a LED bank in the cellar and fiber optic pipes to each room would be cheaper?)

    This will move GNP on and upwards. Lights will become so expensive that they can be taxed. A licence to fit lightbulbs will become obligatory for safety reasons.

    Seriously, this discussion might be valuable to the floater of this lightly-baked idea, since many legitimate problems can probably be solved in the design phase.

  48. Britt Johnston

    low-voltage DC in houses

    I agree with both Tim Schormer in principle, and Graham Ts reminder on Ohms law.

    The point is that each gadget with electronics requires a highly inefficient transformer. The energy savings plus the melted down transformers would allow you to install broad-band copper underflooring.

    I haven't yet worked out how to turn this into the next Microsoft, or what to do with my Rio Tinto shares.

  49. It wasnt me


    Is Dawkins involved in this ? Or that nutter from Reading with the RFID forearm?

  50. Cortland Richmond

    Smart Lights Dim Brain of Britain

    One glaring weakness is that the system will broadcast that "secure" data to nearby radio receivers; the backhaul is just our old friend PLC. Along with that, nearby transmitters will disrupt, reset or shut down the system.

    But using coax or twisted pair to lamp info hubs sounds so "ethernet."

    This is tbe Beeb...breeep breeep breeep breeep buzzzzz


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