Wireless data from every light bulb: Harald Haas on

Posted by: Ben Lillie

What if every light bulb in the world could also transmit data? At TEDGlobal, Harald Haas demonstrates, for the first time, a device that could do exactly that. By flickering the light from a single LED, a change too quick to for the human eye to detect, he can transmit far more data than a cellular tower — and do it in a way that’s more efficient, secure and widespread. (Recorded at TEDGlobal 2011, July 2011, in Edinburgh, Scotland. Duration: 12:52.)

Watch Harald Haas’s talk on, where you can download it, rate it, comment on it and find other talks and performances from our archive of 900+ TEDTalks.

Comments (15)

  • Pingback: Have You Heard about the Li-Fi ? | أو عِلمٌ يُنتَفَعُ بِه

  • Cherukan C commented on Aug 30 2012

    So is it possible aliens have been transmitting using light ?

  • Pingback: Quora

  • Richard Corfield commented on Jun 26 2012

    On the other hand…

    Light doesn’t go through walls so home networks may less likely to cause interference. It does go through windows, but my home network won’t interfere with my neighbours. We use wired network at home because WiFi is not reliable in crowded suburbia.

    In the street if you could modulate the nearest lightbulb to the consumer, tracking them reliably, you could do quite well.

    As a guess – you’re inducing currents in the LED power supply – the induced current carrying the OFDM signal? Clever.

    I wonder how it would interact with PWM dimmers and regulated LED systems. The LED in the desk lamp looks like one that takes a smooth 12V DC supply.

    The usage scenarios, intrinsically safe, immediate proximity comms, sound very good.

    I wonder how existing work with much lower frequency shortwave radio to deal with multipath and multi-transmitter issues could be applied here.

  • Richard Corfield commented on Jun 26 2012

    I wonder how this differs from the old IrDA networking. I remember that at my work’s canteen back in the 90s, but it seems to have gone now. It was two way communications.

    Some notes:

    A visible light system has a lot of noise to deal with. This may make two way comms hard if the terminal node is replying in visible light . A visible reply would be annoying to humans so the uplink would have to be IrDA or some other. (Think mobile phone camera flash permanently on).

    You need to get the data to the lightbulb. Yes there’s network over power which could be made small enough.

    You’re modulating a high power lightbulb. That’s switching a large current at high frequency. Ouch! Maybe they hope to overlay a signal, so not 100% modulation depth? Would it be easier to put something like ZigBee (local radio) in the lighbulb? I understand Zigbee is very small and of course readily available and mitigates a lot of the issues with visible light.

    Camera won’t respond quick enough.

  • Pingback: The plant power plant | Make Wealth History

  • andrew Turton commented on Feb 9 2012

    Fibre Optics?

  • Neal Ehardt commented on Jan 18 2012

    bandwidth = power / distance

    Wireless data transfer always follows this rule. Notice how the lamp is powerful and close. If you put the lamp on the opposite side of the room, the light would have scattered and the sensor probably couldn’t pick up the signal.

    Visible light offers some huge opportunities for networking at the local level. But it won’t be HD-quality unless the the sender
    a) is very close to the receiver; or
    b) uses a laser instead of a lamp. A carefully aimed laser.

    Even at low bandwidth, the cool thing about visible light is that it can act as a handshake or a warning or even just a tag. Radio waves aren’t as well suited to those localized tasks.

  • Pingback: What invisible flicker do different types of light bulbs have? | Q&A System

  • Pingback: “Li-Fi”: wireless communications through light « Atrilife

  • Justin Hayden commented on Sep 14 2011

    Does anyone know how two way data transmission would work with devices like these? I’m a bit of a layman …

  • Pingback: Mass Energy Lab - Energy Efficiency Solutions

  • Pingback: Fredagsmoro: Li-Fi -Frontlysene på bussen snakker til deg? «

  • Timothy Jeter commented on Aug 4 2011

    And yes, this is a fabulous innovation!

  • Timothy Jeter commented on Aug 4 2011

    What was demonstrated was optical HDTV which is very nice. But the proposed networking use case is also very exciting even without SIM/OFDM. Provided that the new hardware (LED based transceivers) would work over a sufficient distance, why couldn’t this be implemented now using VFIR , or the even faster UFIR or Giga-IR protocols? At first glance, it looks as if only minimal changes would be needed to spec out the physical layer -swapping out the infrared hardware for LED hardware. The line of sight issues wouldn’t be resolved but this would still be an excellent advance. Is there a reason why it has to be coupled with SIM/OFDM?