Back in March 2003, some friends and I were hanging
out at a really good coffee shop in Sebastopol. This particular coffee
joint is housed in an old wooden train station building, with very high
ceilings, old style hanging industrial lamps, and even a couple of old
trains serving as small shops, still on the tracks.
Unfortunately, there's no wireless available at this shop (there was, once
upon a time, back when O'Reilly was located across the street from it. But
that was ages ago, and even then the signal wasn't all that it could have
been.) As we sat around drinking our high octane beverages, we got to
talking about the best way to provide coverage in such a huge space. The
room we were in was a common room, open at all hours (the front enterance is
huge, and doesn't even have a door.) While you could put an access point in
one of the enclosed shops in the building, coverage in the open area would
likely be spotty at best. You would want the AP to be located high up off
the ground, where everyone could see it.
Almost simultaneously, we all looked up and noticed the lamps hanging from
the wooden rafters. What if you could house an AP in a package the size of
a large lightbulb, and install it in an existing light socket? This seemed
like a good idea, but how would you get network access to it without running
CAT5 to the socket? Easy: Powerline Ethernet.
With the recent release of the
Siemens' SpeedStream series, such an insane, caffeine-induced idea
as an AP in a lightbulb might be a possibility. These devices are quite
small, about the size of a standard wall wart. They sport a CF wireless
adapter that acts as the AP (actually, it's the same card as the popular Linksys
WCF11 but with a different sticker.) The brilliant bit is that the
wireless network bridges directly to the AC power, so a standard Powerline
Ethernet adapter anywhere on the same power circuit can provide Internet
access to as many APs as you care to plug in. At a mere $85 retail, we
couldn't resist picking one up and seeing what we could do with it.
One of our first concerns was practical rather than
technical. Obviously, if you're going to replace a light bulb with an
access point, the room will likely get darker. That is, unless the AP can
also provide light as well. After fooling with a couple of lighting ideas,
we finally soldered some copper romex onto a fluorescent bulb as a
prototype. The romex is rigid enough to hold the lamp steady, and easy to
solder to. The fluorescent bulb would obviously be dimmer than a 300 watt
spot lamp, but it would be better than nothing. And as a flourescent runs
much cooler, it probably wouldn't turn the guts of the access point to
liquid. This solved the light issue well enough for the moment, but how
could we connect the whole thing to a standard light bulb socket?
One trip to the hardware store later, we had a
variety of Edison plugs, sockets, and adapters. We settled on a simple
extender type of device, with a female socket on one side and a male plug on
the other. Again, the contacts were copper, making it easy to solder on
more romex. We had the basic design together, but what could we possibly
use as a housing?
Tupperware, of course. Adam painted the inside of
a tupperware bowl white, and the entire device just managed to squeeze
inside. We first attempted to take the SpeedStream unit apart to save
space, but it's already tightly packed inside (much of the unit is occupied
by a large transformer.) Besides, keeping the original enclosure made us all
feel a bit more relaxed about plugging the thing in. The Edison plug poked
through the bottom of the bowl, where we simply screwed on another one to
keep it tightly attached.
So with all of the technical considerations accounted for, all that was left
was the all-important marketing phase of the project. Some electrical tape
and one nylon sticker later, the NoCat Night Light was born!
But how well would it
actually work? Wouldn't the fluorescent throw off all sorts of noise that
would interfere with the AP? We certainly thought so. Unfortunately, we
didn't have a machine handy with which to do real throughput testing, but
DSL reports showed a very respectable 2Mbps or so. This was well above the
rated capacity of the cable modem network we were using, so we were
definitely satisfied with the results.
One big improvement to the design would be to replace the fluorescent
bulb with a bright LED array, or even a simple socket so you could use
whatever (low temperature) light source you like. This design makes much
more sense than Siemen's original, as it gets the AP up off of the ground
and above your head, where presumably many more people can see it. Adding
more APs is as simple as screwing in a light bulb, as they bridge directly
to the same AC powerline segment, and terminate at the same ethernet.
While we have no current plans to actually produce the Night Light
commercially, we certainly hope that someone will take the hint and
mass-produce these things. Anything to help the cause of Infinite Bandwidth
Everywhere for Free...
