Smart homes and home automation
by Chris Woodford. Last updated: August 28, 2011.
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!
