

HD video demonstrated streaming over a light bulb - ukdm
http://www.geek.com/articles/mobile/hd-video-demonstrated-streaming-over-a-light-bulb-2011085/

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eande
This demo looks at a first glance convincing, but it is a one way data stream.
The point of using existing infrastructure to fill the room with high speed
data reminds me of all the R&D and attempts made by infrared LEDs. The line of
sight (LoS) problem and interference by sunlight turned even simple
applications like wireless speaker systems to complicated technologies. The
supposedly simple ICs with an AGC (auto-gain-control) turned to complicated
over 110dB solutions with all kind of stability problems. Extracting the
datastream from multipoint sources without data corruption, the increased
power demand for longer distance communication out of mobile devices were all
application problems, which did not allow to get that solution of the ground.
Dr. Haas lab solution looks great, but for me considering the idea form a
practical implementation point of view using visible light via LEDs is a far
distance.

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dpryan
One of the (many) issues with IrDa is that there are severe restrictions on
the power output, since the radiation is invisible. Using visible light,
especially in the context of general purpose lighting, allows you to achieve
much higher SNR.

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bugsy
I suppose at night someone could pick this up if there is a window in the room
being used, but this is no different than normal wifi which can be picked up
outside the house.

More of the problem is that it doesn't work room to room, only line of sight
like with a remote control. Could be useful sending to wireless speakers from
the media player, if the player is in a different location than the TV for
some reason, but in the same room. I suppose it breaks down if you add a
second device unless each one grabs its own specific light frequency and you
have narrow optical filters able to distinguish between them.

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owenmarshall
>More of the problem is that it doesn't work room to room, only line of sight
like with a remote control.

If you could cheaply make the lights transmit _and_ receive, and if the data
were recoverable at very low illumination, you could employ mesh routing --
there's often quite a bit of overlap from lightbulb to lightbulb.

But you're correct -- answering the LoS problem is significant. This could be
very useful in many applications, but it's no silver bullet.

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aganick
While the LoS aspect is potentially desirable in specific applications, I
agree that initially it can be perceived as a limiting factor. Researchers at
Boston University,Rensselaer Polytechnic Institute, and Nakagawa Lab in Japan
are working with software tools to characterize non LoS applications using
reflective and refractive surfaces found indoors. A powerful system can be
envisioned if someone managed to utilize these principles with a device that
contains a receiver with a wide view.

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alok-g
This is not a new idea. Saw a functional demo more than eight years back.
Checkout: <http://www.talking-lights.com/>

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gfodor
This seems to be different. In your link posted, the lights serve as simple
positioning beacons. It seems analogous to the bandwidth we've come to expect
from things like infrared remote controls.

In this case, and indeed the whole point of the talk, is they're transmitting
HD video.

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pyoung
The concept of transmitting data through light has been around forever. For my
undergrad physics lab class in college, my team used a laser to transmit
audio. Another team did a similar thing except they hooked it up to computers
and sent jpeg's. This was probably seven years ago, and this wasn't the first
time that projects like this had been done for this class.

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Magnin
Edison only had you beat by 100 years

<https://secure.wikimedia.org/wikipedia/en/wiki/Photophone>

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js4all
This could also be useful for people who fear electro-smog.

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burgerbrain
Doubtable. Those people are not rational, they'll find a reason to not like
it.

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Magnin
A high-speed pulsing current running nearby.... Should throw off radio and/or
magnetic waves along with the light.

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dctoedt
Prof. Haas talked about using this technology in smartphones, but he didn't
explain what would happen when my phone is in my (dark) pocket.

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Geee
This would be useful for some ad-hoc broadcasts (whatever that would be), not
sure about any other use.

