How Smart Homes Work

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Introduction to How Smart Homes Work

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Could this remote control program your entire house?
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When you're not home, nagging little doubts can start to crowd your mind. Did I turn the coffee maker off? Did I set the security alarm? Are the kids doing their homework or watching television?

With a smart home, you could quiet all of these worries with a quick trip online. When you're home, the house takes care of you by playing your favorite song whenever you walk in or instantaneously dimming the lights for a movie. Is it magic? No, it's home automation. Smart homes connect all the devices and appliances in your home so they can communicate with each other and with you.

Anything in your home that uses electricity can be put on the home network and at your command. Whether you give that command by voice, remote control or computer, the home reacts. Most applications relate to lighting, home security, home theater and entertainment and thermostat regulation.

The idea of a smart home might make you think of George Jetson and his futuristic abode or maybe Bill Gates, who spent more than $100 million building his smart home [source: Lev-Ram]. Once a draw for the tech-savvy or the wealthy, smart homes and home automation are becoming more common. About $14 billion was spent on home networking in 2005, and analysts predict that figure will climb to more than $85 billion by 2011 [source: Regan].

Inside Bill Gates' Home
Microsoft Chairman Bill Gates' home just outside of Seattle, Wash., might be the most famous smart home to date. Everyone in the home is pinned with an electronic tracking chip. As you move through the rooms, lights come on ahead of you and fade behind you. Your favorite songs will follow you throughout the house, as will whatever you're watching on television. You can entertain yourself by looking at Gates' extensive electronic collection of still images, all available on demand. The chip keeps track of all that you do and makes adjustments as it learns your preferences. When two different chips enter the same room, the system tries to compromise on something that both people will like.

Why are smart homes becoming more popular? Are they easy to operate? And why did that light just turn off behind me? On the next page, we'll take a look at the technology in a smart home.

Smart Home Software and Technology

Smart home technology was developed in 1975, when a company in Scotland developed X10. X10 allows compatible products to talk to each other over the already existing electrical wires of a home. All the appliances and devices are receivers, and the means of controlling the system, such as remote controls or keypads, are transmitters. If you want to turn off a lamp in another room, the transmitter will issue a message in numerical code that includes the following:

An alert to the system that it's issuing a command,
An identifying unit number for the device that should receive the command and
A code that contains the actual command, such as "turn off."

All of this is designed to happen in less than a second, but X10 does have some limitations. Communicating over electrical lines is not always reliable because the lines get "noisy" from powering other devices. An X10 device could interpret electronic interference as a command and react, or it might not receive the command at all. While X10 devices are still around, other technologies have emerged to compete for your home networking dollar.

Instead of going through the power lines, some systems use radio waves to communicate, which is also how WiFi and cell phone signals operate. However, home automation networks don't need all the juice of a WiFi network because automation commands are short messages. The two most prominent radio networks in home automation are ZigBee and Z-Wave. Both of these technologies are mesh networks, meaning there's more than one way for the message to get to its destination.

The green and red dots represent devices that could be connected to your smart home network.

Z-Wave uses a Source Routing Algorithm to determine the fastest route for messages. Each Z-Wave device is embedded with a code, and when the device is plugged into the system, the network controller recognizes the code, determines its location and adds it to the network. When a command comes through, the controller uses the algorithm to determine how the message should be sent. Because this routing can take up a lot of memory on a network, Z-Wave has developed a hierarchy between devices: Some controllers initiate messages, and some are "slaves," which means they can only carry and respond to messages.

ZigBee's name illustrates the mesh networking concept because messages from the transmitter zigzag like bees, looking for the best path to the receiver. While Z-Wave uses a proprietary technology for operating its system, ZigBee's platform is based on the standard set by the Institute for Electrical and Electronics Engineers (IEEE) for wireless personal networks. This means any company can build a ZigBee-compatible product without paying licensing fees for the technology behind it, which may eventually give ZigBee an advantage in the marketplace. Like Z-Wave, ZigBee has fully functional devices (or those that route the message) and reduced function devices (or those that don't).

Using a wireless network provides more flexibility for placing devices, but like electrical lines, they might have interference. Insteon offers a way for your home network to communicate over both electrical wires and radio waves, making it a dual mesh network. If the message isn't getting through on one platform, it will try the other. Instead of routing the message, an Insteon device will broadcast the message, and all devices pick up the message and broadcast it until the command is performed. The devices act like peers, as opposed to one serving as an instigator and another as a receptor. This means that the more Insteon devices that are installed on a network, the stronger the message will be.

On the next page, we'll take a look at the products you'll need to get your smart home running.

Setting Up a Smart Home

X10, Insteon, ZigBee and Z-Wave just provide the technology for smart home communication. Manufacturers have made alliances with these systems to create the products that use the technology. Here are some examples of smart home products and their functions.

Cameras will track your home's exterior even if it's pitch-black outside.
Plug your tabletop lamp into a dimmer instead of the wall socket, and you can brighten and dim at the push of a button.
A video door phone provides more than a doorbell -- you get a picture of who's at the door.
Motion sensors will send an alert when there's motion around your house, and they can even tell the difference between pets and burglars.
Door handles can open with scanned fingerprints or a four-digit code, eliminating the need to fumble for house keys.
Audio systems distribute the music from your stereo to any room with connected speakers.
Channel modulators take any video signal -- from a security camera to your favorite television station -- and make it viewable on every television in the house.
Remote controls, keypads and tabletop controllers are the means of activating the smart home applications. Devices also come with built-in web servers that allow you to access their information online.

Don Farrall/Photodisc/Getty Images
This keypad will send a message to your lamp.

This keypad will send a message to your lamp.These products are available at home improvement stores, electronics stores, from technicians or online. Before buying, check to see what technology is associated with the product. Products using the same technology should work together despite different manufacturers, but joining up an X10 and a Z-Wave product requires a bridging device.

In designing a smart home, you can do as much or as little home automation as you want. You could begin with a lighting starter kit and add on security devices later. If you want to start with a bigger system, it's a good idea to design carefully how the home will work, particularly if rewiring or renovation will be required. In addition, you'll want to place strategically the nodes of the wireless networks so that they have a good routing range.

While the networks claim that the products are easy to program and use, about 60 percent of homebuilders who have installed home automation devices hired professional help [source: Regan]. If you're looking for a technician, check if they have CEA-CompTIA certification. This certification is the result of a partnership between the Consumer Electronics Association (CEA) and the Computing Technology Industry Association (CompTIA), and it represents proficiency in installing, maintaining and troubleshooting any vendor's home networking equipment.

Smart Appliances

While most home automation technology is focused on lighting, security and entertainment, smart appliances may be on their way as well. Ideas include:

Trash cans that monitor what you throw away and generate online orders for replacements.
Refrigerators that create dinner recipes based on the ingredients stored inside.
Washers and dryers that send text message alerts when their cycle has ended.

The cost of a smart home varies depending on how smart the home is. One builder estimates that his clients spend between $10,000 and $250,000 for sophisticated systems [source: McKay]. If you build the smart home gradually, starting with a basic lighting system, it might only be a few hundred dollars. A more sophisticated system will be tens of thousands of dollars, and elements of home theater systems raise the cost of a system about 50 percent [source: Gloede].

Is it worth the money? To learn more about the benefits of smart homes, go to the next page.

Smart Home Benefits

Smart homes obviously have the ability to make life easier and more convenient. Who wouldn't love being able to control lighting, entertainment and temperature from their couch? Home networking can also provide peace of mind. Whether you're at work or on vacation, the smart home will alert you to what's going on, and security systems can be built to provide an immense amount of help in an emergency. For example, not only would a resident be woken with notification of a fire alarm, the smart home would also unlock doors, dial the fire department and light the path to safety.

baby in crib with surveillance camera on it

Thomas Jackson/Stone/Getty Images
With smart home security, you can check on your little one from anywhere.

Here are a few more examples of cool smart home tricks:

Light a path for nighttime bathroom trips
Instantly create mood lighting for time with that special someone
Program your television so that your children can watch only at certain times
Access all your favorite DVDs from any television in the home
Have your thermostat start warming the bedroom before you get out of bed so that it's nice and toasty when you get up
Turn on the coffee maker from bed

Smart homes also provide some energy efficiency savings. Because systems like Z-Wave and ZigBee put some devices at a reduced level of functionality, they can go to "sleep" and wake up when commands are given. Electric bills go down when lights are automatically turned off when a person leaves the room, and rooms can be heated or cooled based on who's there at any given moment. One smart homeowner boasted her heating bill was about one-third less than a same-sized normal home [source: Kassim]. Some devices can track how much energy each appliance is using and command it to use less.

Religious Benefits of Smart Homes

For some members of the Jewish faith, installation of a smart home doesn’t just make life simpler, it can aid religious practice. Some Orthodox Jews are prohibited to turn lights on or off, or operate any sort of electricity, on the Sabbath. A programmed light system can maintain a home at an adequate state of lighting without requiring any human interaction [source: Forbes].

Smart home technology promises tremendous benefits for an elderly person living alone. Smart homes could notify the resident when it was time to take medicine, alert the hospital if the resident fell and track how much the resident was eating. If the elderly person was a little forgetful, the smart home would perform tasks such as shutting off the water before a tub overflowed or turning off the oven if the cook had wandered away. One builder estimates that this system could cost $20,000, which is less expensive than a full-time nursing home [source: Venkatesh]. It also allows adult children who might live elsewhere to participate in the care of their aging parent. Easy-to-control automated systems would provide similar benefits to those with disabilities or a limited range of movement.

Smart Dog Houses?

Pets can benefit from smart technology as well. Here's a sample of automated products for man's best friend:

Devices that stop a dog's barking by emitting ultrasonic tones.
Feeders that give your pet a preset amount of food at three selected times per day.
Pet carriers that automatically heat or cool your pet as the temperature changes.

To see more pet technology, visit SmartHome.com's Pet Care page.

Smart homes look great on paper, but are they for everyone? On the next page, we'll look at some of the disadvantages of this technology.

Smart Home Challenges

A smart home probably sounds like a nightmare to those people not comfortable with computers. Those who routinely fumble around with a remote control just trying to change the television channel might have stopped reading by now.

It may be your fear that if you try to turn on the television in your smart home, lights will start flashing, and this does happen occasionally. (Power outages, however, activate backup battery and safe mode, which means you can still perform tasks like unlocking a door manually). One of the challenges of installing a smart home system is balancing the complexity of the system against the usability of the system. When planning the system, it's important to consider a few factors:

How large will the system be?
What kinds of components are part of the system? Are they basic, such a light dimmer, or more imposing, like an alarm system or a video camera?
How intuitive will the system be to a non-user?
How many people will be required to use the system?
Who will know how to operate the system? Who will know how to maintain the system and address failures? How often will people who can only operate the system be left alone in the home?
How easy is it to make changes to the interface? For example, if your house is programmed to wake you up at 7 a.m., how will you let it know that you're away overnight on business or sleeping in on a Saturday?

Image Source Pink/Getty Images
Smart homes may be difficult for some people to operate.

For these reasons, it may be easier to start with a very basic home network and expand as enhancements are needed or desired. However, there's some concern that with the market so new, technologies are developing all the time, sometimes leaving old versions of products useless. If you invest too soon, you may end up with a model that has impossible-to-find components and spare parts. Like many new technologies, smart homes require a significant investment to keep up.

Smart homes also come with some security concerns. Hackers who access the network will have the ability to turn off alarm systems and lights, leaving the home vulnerable to a break-in, or the theft could be more electronic. If music is saved on a hard drive so that it can be played around the house, make sure that sensitive information, such as passwords or identifying numbers, are saved elsewhere.

Some smart home devices also raise ethical questions about privacy, or evoke an Orwellian feeling of "Big Brother." It's great to be able to check in on a four-year-old in his room while you're cooking dinner in the kitchen, but how will that child feel when he's constantly monitored through puberty? The information that a smart home collects might start to feel like a weapon to a teenager who gets caught sneaking in after a late-night party. When setting up a smart home, it's a good idea to discuss it with the whole family first.

Of course, there's also the question of whether an individual needs all this technology. Is our society really so lazy that we can't turn flip a light switch? It's an interesting argument, but smart homes are coming. The good news is that with all the time we save from home automation, we'll have time to work on other pursuits. Like developing robot maids.

To learn more about smart homes, visit the links on the next page.

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How Smart Homes Work