Re: ~e; fluorescent lights

From human being <>
Date Thu, 9 May 2002 22:54:43 -0500
In-reply-to <p05100309b8ff743414d8@[]>
References <a05111702b8fe2caaec50@[]><p05100309b8ff743414d8@[]>

  [Very interesting article Sj, thanks for the fwd. here are a few
  quotes from: ]

"To create fluorescent tubes that can communicate, their inventor, Dr. Steven
Leeb, has modified ordinary fluorescent fixtures so that they beam data as
well as illumination. Dr. Leeb, who teaches circuit design and other subjects
at M.I.T., does this by changing one component in the fixture to produce
fluctuations in the light that can be read as a digital signal. These
fluctuations, imperceptible to the eye, are easily detected by light
sensors that pick up the signals and pass them to processors and software
that produce voice, music or text messages. The lights may be linked to
create inexpensive data networks.

The process of using the lights to transmit data starts with a ballast, the
component of fluorescent tubes that controls the current needed to create
the light. The ballast causes the vapor inside the tube to ionize many
times a second, creating the imperceptible flicker. Dr. Leeb has modified
the ballast to modulate the number of times per second that the light flickers.

"The ballast is what makes the magic happen," Dr. Leeb said. "We drop it in,
just as we would replace a bulb."

If, for instance, the light is flickering at 40 kilohertz, or 40,000 times
per second, which is standard for modern fluorescent fixtures using
electronic ballasts, the modified ballast might alter the frequency
slightly to create a digital 1, and then alter it slightly differently
to create a digital 0, thus producing a binary datastream.

"The trick is that our ballast moves the frequency around in such a way that
the light doesn't flicker visibly," Dr. Leeb said.

  [has me thinking about 2 things. one being that fluorescence is a few
  hundred years old. {see note-1}, it seems. gases glowing in glass,
  luminous. but then, was not understood and may have been forgotten, as
  with fuel cells, or other EM technologies (such as the Tesla tech e.g.]

  [the other thought was that of a sculptor who uses flourescent lightbulbs
  in their work. i thought it was dan flavin but my last attempt at finding
  out (going to a museums archivists) did not solve the riddle. the artist
  made both white-light (varients) and multi-colored tubes of fluorescent
  light sculptures. have seen only a few, yet was caught by surprise at
  seeing one, as it changed my relation to the technology and the often
  buzzing and broken ballasts and flickering noise of the lights themselves.
  probably mentioned here before, or elsewhere, but so too, digital signals
  can go through e-wires in houses (local area networks through power out-
  lets and plugs) and also through structural steel in buildings, and is
  also reconstructed for various purposes, from pipes that are vibrating.]

note-1: 1709 C.E. - Francis Hawksbee (English) creates "a primitive
ELECTRIC LIGHT" machine, (17) that eventually evolved into "'s
brilliant fluorescent lamps and the blue-white mercury vapor lamps
in the streets and factories [as a practical result]." (18)  from:

  the electromagnetic internetwork-list
  electromagnetism / infrastructure / civilization