Smart homes and home automation
Last updated: November 5, 2009.
Back in 1923, brilliant Swiss-born architect Le Corbusier (1887–1965)
described a house as "a machine for living in"—and slowly, during the 20th century,
that metaphor turned into reality. First, the arrival of convenient, electric power started to
strip away the drudgery from all kinds of domestic chores, including
washing clothes and
dishes and
vacuuming the floor. Then, when
transistors
made electronics more affordable in the mid-20th century, appliances
started to control themselves in a very limited way, using built-in
sensors and programmers. But it's only now, in the 21st century, that
the vision of the fully automated home is actually being realized.
Thanks to the Internet, it's easy to set up
virtually any electric appliance in your home so you can control it
from a Web browser anywhere in the world. Like the idea of living in
a smart home? Let's take a closer look at how it might work!
Photo: Future homes will be smart as well as eco-friendly.
Photo by John Avenson
courtesy of US
Department of Energy/National Renewable Energy Laboratory (DOE/NREL).
What is a smart home?
A smart home is one in which the various electric and
electronic appliances are wired
up to a central computer control system so they can either be
switched on and off at certain times (for example, heating can be
set to come on automatically at 6:00AM on winter mornings) or if certain
events happen (lights can be set to come on only when a
photoelectric sensor detects that it's dark).
Most homes already have a certain amount of "smartness" because many appliances already
contain built-in sensors or electronic controllers. Virtually all
modern washing machines have programmers that make them follow a
distinct series of washes, rinses, and spins depending on how you set
their various dials and knobs when you first switch on. If you have a
natural-gas-powered central heating system, most likely you also have
a thermostat on the wall that switches it on and off according to the
room temperature, or an electronic programmer that activates it at
certain times of day whether or not you're in the house. Maybe you're
really hi-tech and you have a robotic vacuum cleaner that constantly
crawls around your floors sweeping the dust?
Photo: Simple electronic controls like this thermostat give all our homes a certain
amount of "smartness." Photo by Warren Gretz courtesy of US
Department of Energy/National Renewable Energy Laboratory (DOE/NREL).
All these things are examples of home automation, but they're not really what we mean by a
smart home. That concept takes things a step further by introducing
centralized control. In the most advanced form of smart home, there's a computer that
does what you normally do yourself: it constantly monitors the state of
the home and switches appliances on and off accordingly. So, for
example, it monitors light levels coming through the windows and
automatically raises and lowers blinds or switches the lights on at dusk.
Or it detects movements across the floor and responds appropriately:
if it knows you're home, it switches light and music on in different
rooms as you walk between them; if it knows you're out, it sounds an
intruder alarm.
How do smart homes work?
Assuming you're not (yet) in the Bill Gates league of having a
multimillion dollar smart home built from the ground up, you'll probably be more
interested in adding a bit of automation to your existing appliances
with as little fuss as possible. Modestly smart homes like this
range in complexity from basic systems that use a few plug-in modules and
household electricity wiring to sophisticated wireless systems you
can program over the Internet. Here are the three most common flavors:
Plug-in X-10 modules
Developed in 1975, the oldest and best-known smart home automation system is called
X-10
(sometimes written "X10") and uses your ordinary
household electricity wiring to switch up to 256 appliances on and off with no
need for any extra cables to be fitted.
You plug each appliance you want to automate into a small control unit (usually called a module)
and plug that into an ordinary electrical power outlet. Using a small
screwdriver, you then adjust two dials on each module. One dial is
what's called the house code and you set this to be a letter from A
through P. You can use the house code to link appliances together (for example, so
all the lamps on the first floor of your home can be controlled as a group).
The other dial is set so each individual appliance has a unique
identifier known as its unit code, which is a number 1-16.
Next, you plug a central controller unit into another electrical socket and program it to switch the various
appliances on and off (identifying them through their codes) whenever
you wish.
Photo: An X-10 module used for controlling household appliances made by
Powerhouse. You can see the two dials used for setting the unit code (top) and house code
(bottom). Photo by Phylevn
published on Flickr
in 2009 under a Creative Commons Licence.
How does it work? The central controller sends regular switching
signals through the ordinary household wiring, effectively treating
it as a kind of computer network. Because these signals work at roughly twice the switching frequency
of ordinary AC power (which works at 50-60Hz), they don't interfere with it
in any way. Each signal contains a code identifying
the unit it relates to (a table lamp in your living room, perhaps, or
a radio in your bedroom) and an instruction such as turn on, turn off,
or (for lamps) brighten, or dim. Although all the control units listen
out for and receive all the signals, a particular signal affects
only the appliance (or appliances) with the correct code.
Apart from appliances that receive signals, you can also plug in
sensors such as motion detectors,
thermostats, and so on, so the system will respond automatically to
changes in daylight, temperature, intruders, or whatever else you
consider important. With
most systems, you can also switch appliances on and off with a
handheld remote control (similar to a TV remote). The remotes either
send signals directly to each module using radio wave (RF)
signals or communicate with the central controller, which relays the signals
accordingly.
X-10 has become an international standard for controlling appliances, but it's not the only system that works this way.
Computer-controlled X-10 system
If you're just automating a few security lights, a basic X-10 system with a few
modules and a single controller should be more than enough for your
needs. But if you want to run a more sophisticated setup, with
many different appliances coming on and off in all kinds of different
ways, you might want to use your home computer as the controller
instead. That's easy too! You buy an X-10 home computer interface kit
comprising a module (which plugs into a power outlet like any other
module), an interface cable to connect the module to your computer
(using either a standard serial or USB port), and some software.
Typical software shows a graphical representation of all your
appliances and lets you set on/off patterns for a day, a week, or
even longer. You can also create your own macros so groups of
appliances switch on and off in a certain sequence at a certain time
each day. There's X-10 software for both Windows and Linux systems.
Wireless Internet system
Security is one of the biggest reasons why many people are interested in smart homes. If
you're away at work or on holiday, making your home seem lived in is
a good way to deter intruders. A basic X-10 system can turn the
lights and the TV on and off at unpredictable times, but if you
really want to push the boat out on security, a wireless,
Net-connected system is much better. Effectively, it's a
computer-controlled X-10 system with an interface you can access over
the Web. With a system like this, you can hook up webcams to watch
your home (or your pets), switch appliances on and off in real time,
or even reprogram the whole system. Harmony Home Automation is an
example of a system that works like this.
Photo: You can use a wireless router to control an X-10 system remotely over the Internet,
but you'll need to set up an IP address so you can access your router and computer securely from elsewhere.
Dynamic DNS and Port Forward
are very useful if you're going to do this kind of thing.
Another view: do you really need a smart home?
If you're elderly or disabled, home automation systems like this can make all the
difference to your quality of life, but they bring important benefits
for the rest of us as well. Most obviously, they improve home security,
comfort, and convenience. More importantly, if they incorporate
energy monitors, such as thermostats, or sensors that cut the lights
to unoccupied rooms, they can help you reduce household energy bills;
automated systems such as Bye Bye Standby, which cut the power to
appliances when they're not being used, can dramatically reduce the
energy wasted by appliances such as washing machines,
dishwashers,
and TVs when they're not actually being used.
But do you really need things like this? Do you need to buy even more appliances just
to control the ones you already have? Isn't it just as easy to
get into the habit of switching things off yourself? Gadgets that
kill your TV's standby mode sound cool, but how hard is it to pull
out the plug? What about switching the TV off altogether and reading a book? Or putting your
games console away in the cupboard and getting into the habit of taking walks in the country
instead? And instead of going to great lengths to wire up your house for while you're away
on vacation, how about befriending the neighbors and asking them to look out for you instead?
For many of us, a house really is a machine for living in—and if that's the way you like
living, it's just fine. But it's important to remember that there are
plenty of alternatives to living that way as well. If small is beautiful and
simple is best, the smartest home might be one that has no gadgets at all!
Further reading
Books
Products and systems
Please note that not all systems are available in all countries.
