CIRCUIT CELLAR • MARCH 2014 #284
70
TESTS & CHALLENGES
Sponsored by WIZnet — circuitcellar.com/wiznet2014
there are powerline communication “starter
kits” that come with a pair of adapters (such
as my Rosewill RPLC-201KIT) in the $20 to
$40 price range.
If you’re recalling the shaky early days
of power line communication, be advised the
latest generation of gear works a lot better.
There can still be situations where particular
AC outlets are hard to reach, but usually
you can find a nearby one with a decent
connection.
Since these new adapters are designed
to handle streaming AV, I’ve found that even
marginal connections (as indicated by the
adapters signal quality LED) work fine with
my low-bandwidth apps. Presumably the
powerline adapter and/or W5500 are working
their own magic handling any issues (e.g.,
automatic retry of corrupted/lost packets,)
which is fine by me.
If there isn’t AC nearby and you’re faced
with stringing wire, Power over Ethernet
(PoE) is the way to go. It’s perfect for things
such as security webcams and VoIP phones,
and now the popularity of those applications
has fueled the market with new suppliers and
lower prices (less than $100 routers and less
than $10 modules) for IEEE standard 802.3af
PoE gear.
An even simpler roll-your-own option
is “Passive PoE,” which uses the four spare
wires in a standard Ethernet cable for power
transmission (see Photo 4). Note that this
hack doesn’t work with Gigabit Ethernet
(which uses all eight wires) or “Active PoE”
(i.e., IEEE standard 802.3af) gear, just plain
vanilla 10/100.
You may have to consider voltage
drop, especially for long cable runs (iup to
PHOTO 3
My garage door monitoring “Thing” uses a powerline adapter to connect with the household LAN.
PHOTO 4
All you need are some cheap “cheater” cables (splitter and injector) and a variable power supply to homebrew
your own “Passive PoE” solution.
PHOTO 2
The WIZ550io module has everything you need (e.g., transformer,
RJ45, and MAC address) to plug and play.
Copyright © 2014 by Circuit Cellar, Inc.
Subscription: http://circuitcellar.com/subscription/
Manymanuals.com
Manymanuals.de
Manymanuals.fr
Manymanuals.it
Manymanuals.pl
Manymanuals.cz
Manymanuals.es
Manymanuals-pt.com
Comentarios a estos manuales