It's 6:25 p.m., and you guide your car into your garage after an exhausting day at the office. By the time you reach the door, the downstairs lights are already on, and the thermostat is set to a comfortable 68 degrees. You're just in time to catch the local news, so the television in the family room clicks on and is tuned to your favorite channel. Sound like a scene from a sci-fi movie? With some add-on hardware and a versatile application called XTension, you can automate your household appliances with your Mac today.
The XTen in XTension stands for X10, a popular home-automation protocol that transmits signals over existing electrical wiring. Originally developed more than 20 years ago, X10 systems include four components: hardware modules that control lights and other electrical devices; interfaces that send and receive X10 signals from the modules; remote controls; and computer programs -- such as XTension -- that tell the interface what to do. (Several vendors, including X10 Wireless Technology, Marrick, and Radio Shack, sell X10 hardware, which typically costs about $5 to $15 per item. If you have a USB-only Mac, you'll also need a USB-to-serial adapter to connect your computer to an X10 interface.)
With XTension, you can view your X10 modules in List or Icon view. Unlike MouseHouse 2.0 (3.0 mice. , February 1999) or Thinking Home (3.0 mice. , April 2000), XTension doesn't let you download commands to an X10 interface where they can run on a schedule without your Mac. But that's not a liability -- part of the power of Xtension is that it allows the Mac to generate X10 commands in real time, whenever the modules require them. So, you can, for example, set up a script that runs whenever a door opens or a light is switched on. You will need a dedicated computer that's on at all times, but fortunately, XTension runs on any 680X0 or PowerPC-based Mac with System 7.1 or later, so it's an ideal job for an older computer.
Because XTension works in real time, its power extends far beyond activating timed events, such as turning on outside lights at sunset or heating up the coffee pot at 7 a.m. You can set up scripts to have modules respond to remote sources in addition to instructions from the Mac. X10 sells a wireless controller, and with this device and a simple XTension script, you can control as many lights and appliances as you like with a handheld remote. Also, because XTension uses AppleScript as its scripting language, it can even control and interact with other applications.
Although you don't have to be a programming whiz to write basic XTension scripts, complex functions, such as boosting your thermostat when the outside temperature drops, are more challenging. To help get you started, XTension's electronic manual includes an introduction to scripting, and Sand Hill's Web site provides loads of helpful ideas and tips.Home on Autopilot: XTension shows you a graphical view of all of your X10 modules, and allows you to script your appliances to do just about anything.