Hardware Reference
In-Depth Information
Standard Case
The next step after the simple case shown earlier is to utilize wireless controllers. Most of the equipment on the
market uses radio frequency (RF, at 433MHz), allowing devices to be controlled from the garden, through walls,
through floors, and through ceilings. The precise range varies according the materials through which the signal is
traveling, the other devices operating in the 433MHz range such as TV senders or RFID readers, and the strength of
the transmitter, with some mid-price devices having a 25-meter range when unobstructed.
Because RF has no connection to the power lines, it also requires the use of an RF-to-X10 gateway, which plugs
into a wall socket, picks up the RF signals sent by any suitable controller, and places the data message onto the X10
power line. Although such devices have a configurable house code, their unit code is invariably hard-coded to one, so
be sure to avoid using such a code for any devices if you plan on migrating from a simpler environment.
Adopting an RF-to-X10 gateway in this way provides a lot more scope for automation, because controllers are
wireless and no longer need to be situated next to a power socket, enabling them to appear in bathrooms where such
sockets contravene domestic housing regulations in many countries by being within 1.5 meter of a water tap, as is
the case in the United Kingdom, for example. There are RF controllers that stick to walls, sit on desks, and even fit
on key rings!
The primary issue with RF remote control is that rogue transmissions are very difficult to filter out,
1
meaning
someone outside could conceivably control your inside lights.
Fully Automated
The big difference between this and the standard automated example is the inclusion of a computer interface,
generally the CM11, covered later in this chapter and shown in Figure
1-14
. This doesn't have an X10 address, but it
passively monitors the messages on the power lines and passes them back to the computer via the serial or USB port.
Similarly, the computer can use the device to place new messages onto the power lines, which will be picked up by
the devices you already have. Once a computer is involved, the possibilities open up. I'll be covering these possibilities
later in this chapter when covering the range of available X10 devices.
It is perfectly possible to have a fully automated solution using the computer that doesn't use RF wireless or suffer
its problems. Instead of RF, you can use a more secure transport and protocol such as HTTPS through a web browser
that could be on an iPod touch, iPhone, or other suitably connected handheld device such as a mobile phone to send
the message to the computer, which is turn places suitable data on the power line.
Assigning Addresses
Because every automated device in your house needs an address, it makes sense to assign them something sensible
and memorable at the start of the process. The most important thing to remember here is that your X10 configuration
can grow as your budget increases, and you're more likely to add a couple of new appliances in your house than you
are to add a couple of new rooms!
Determining a house code is simple enough. If you have a neighbor, or neighbors, with an X10 setup, then pick
any letter that isn't used by them. It might sound obvious, but you should
talk
to them about whether they have
one and what codes they're using. Just because you're not seeing any irrational behavior at the moment doesn't
mean there won't be a conflict in the future. I would also avoid using P, since some devices (the TM13UAH, for
example) considers P as “accept message on any house code,” which could be confusing and problematic. My only
other advice here is to avoid A, which is the default for most equipment. This has two benefits. First, it ensures that
anyone “playing” with X10 devices in the neighborhood won't accidentally stumble onto your network and cause
!&ARADAYCAGEWORKSBUTISNOTGENERALLYPRACTICALINAHOMEENVIRONMENT
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