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."

Comments

Great. More broadband noise

[Anonymous Coward]

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
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/isplc2003 /isplc2003a 7-4.pdf

Re:I don't understand the point of this....

[Suidae]

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.

Re:Great. More broadband noise

[Ungrounded Lightning]

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.