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The NoCat Wireless Access Point/Night Light
cascadefx writes "O'Reilly's Hacks page has a really great article about a wireless access point that was on display at the recent Emerging Technology Conference. The folks at NoCat.net rigged up a Siemens Speedstream series access point with a low power ultraviolet light to create a wireless lightbulb. Just screw it in place and combine powerline ethernet with a wireless network... and a light, to create a wireless lightbulb. Ubiquitous networking, here we come."
Everybody who thinks that powerlines are a great way to run ethernet through your house forget that all of the wire is unshielded thereby creating a large antenna. This typically results in static noise on frequencies up to 80Mhz. I also wonder how hard it would be to just listen to the
3 /isplc2003a 7-4.pdf
network and attach to it. I am still amazed that
the FCC lets any of this trash through. If you
are not convinced go here:
http://www.arrl.org/tis/info/HTML/plc/
And no this does not just affect amateur radio.
Ever thought about radio astronomy
http://www.qsl.net/jh5esm/PLC/isplc200
Don't confuse in-house PLC with distribution line (eg. from the power company) PLC.
From the same article:
"To date, with hundreds of thousands HomePlug systems sold, ARRL does not have any complaints of interference."
The ARRL is worried about PG&E selling broadband via this technology, not your average low-end linksys or siemens user.
X10 is also extremely slow. Without data compression you can max out at less than 8 bytes per second;
X10 transmits only during the zero crossing of the AC powerline. If memory serves its a 10kHz signal for 1mS. One bit every 1/60th of a second, less framing and retransmissions (X10 includes some redundancy to reduce errors). Effective data rate even with compression would probably be less than 4 bytes per second.
Everybody who thinks that powerlines are a great way to run ethernet through your house forget that all of the wire is unshielded thereby creating a large antenna. This typically results in static noise on frequencies up to 80Mhz.
And that's NOTHING compared to the noise generated on the wiring by connected non-communication appliances.
- Motors. (Especially brush-type, such as vacuum cleaners or hair driers.)
- Switching-type light dimmers.
- Arc lights (fluorescent, "neon" gas discharge tubes, vapor-capsule, etc.)
- Welders.
- Switching-regulators in electronic appliances.
- DIODES in power supplies.
- ANY load turning on or off.
Heck: Even an incandescent bulb produces broad-spectrum audio-through-radio interference on the line - though nothing like what a defective bulb produces as it flickers. (And an old carbon-filiment lamp in a closet has been known to knock out radio reception for much of a city block.)
Be prepared for a LOT of packet corruption - meaning a lot of packet loss plus enough that get past all the redundancy checks to corrupt the actual traffic - if you ever attempt to use a power line for network traffic.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
With the solar array in space it is not ubstructed by clouds or earth. The microwave energy can be focused on just the base station to such an extend that it is not a health concern (below approved levels) to surrounding areas.
The solar array in space could be quite large. I heard someone suggesting 15 miles in length.
Some current uses for this method might be to set up an emergency power connection between to sites in the event that the power lines have been wrecked.
CS
Actually I just picked up two of the Ethernet-to-Powerline adapters off of buy.com for $40/each and free shipping (Thank You Froogle!).
They also have a bundle One 802.11b-to-Powerline and One Ethernet-to-Powerline for $75.
I already have wireless, but this is cheaper than buying a new NIC+PCI adapter for my linux box (the SMC one I have gets terrible connections) and it gives me wired for my Playstation2 as a bonus.
In any case, I kind of don't see the point. Why not just a a wireless repeater? With 802.11a/g that's a lot faster than this, and it means you don't have two separate networking technologies to hassle with. And usually, you want to cover an area completely anyway, so all wireless access points need to overlap, which mean that they can act as repeaters.
Sorry, but you're mistaken.
Modern car stereos have two power leads going to them. One lead goes directly (ok, maybe through a fuse) to the battery, while the other goes to the ignition switch. Yes, when you shut your car off, the stereo powers off, but this doesn't mean that all power has been cut. The stereo keeps a constant power feed on the car's battery so it will remember the presets, as well as keep the clock up to date.
Yes, I've heard of NVRAM. But NVRAM still needs some kind of power to keep its previous settings. This is why your digital alarm clock has a battery backup, and your computer's motherboard has a CMOS battery.