Home Automation Hardware
Hardware is the meat of the home automation system--it's what carries out your commands and actually gets stuff done. This page covers both the computer hardware and the HA hardware that makes up my system.
First thing's first--in order to have an intelligent house, you need to give it a brain. While there are a proliferation of plug in controllers and timers out there, you really need to have a dedicated computer to run control software and accept inputs from complex devices. Additionally, having a dedicated computer allows you link your system into the internet, giving you access to virtually limitless quanities of data.
A home control computer doesn't have to be good. In fact, complexity can be a liability--the more complex the machine, the more things there are to go wrong. Since you want your computer to run 24/7 with as few interruptions as possible, the best thing to do is get a relatively capable machine and then make its tasks as simple as possible. Basically, you want to bore your computer--if it can perform tasks far more complex than the ones you ask it to perform, you'll have a good margin for error and a reliable system.
Personally, I use an old Powerpec PC (the store brand at Microcenter, our local computer place). It was given to me because it was completely inundated with spyware--I had to wipe the drive three times just to get rid of the popups. It runs XP, and it has a 60gb harddrive. Since most HA functions are carried out using radio waves or powerline connections, the computer doesn't have to be centrally located--mine is in the attic.
If you want to invest in a new computer, get the bottom-of-the-line model from HP or Dell. For a couple hundred bucks, you'll have a machine that is probably far better than you need it to be. If you don't want to bother buying a new computer, see if you can scrounge one from a friend--you can always install a new OS and add some memory. The other option is to run your software on an existing computer (preferably not one in a sleeping area).
Choosing a Standard
Once you have a computer to run your control software, you'll need things to control. Luckily, this is one of the easiest parts of the whole production. There are already a few mass-market modular home automation solutions out there, and you can get modules to control elements of your home for as little as $10-20 each.
Most of the mainstream ones work by sending signals through your home's power lines--all you have to do is plug in a little box or install a special lightswitch, and your home will be remote-controllable. If you're the sort of person who enjoys reading complex, jargon-filled reports on electromagnetic theory, there's a great explanation of the actual mechanics of these systems here.
The two dominant standards for powerline transmission are Insteon and X10. I use X10, chiefly because the modules are cheap and easy to find. With software like Powerhome, you can opt to use both, but this page will focus on X10.
In order for your computer to send commands, you'll need an interface. These either connect to your computer via USB or through a serial cable. Interfaces serve two purposes--they connect your computer to your home's powerlines, and they recieve radio signals from modules, allowing them to communicate with your computer.
You can buy interfaces through websites like Smarthome, or even through mainstream places like Amazon.com--just make sure they're compatible with Powerhome and X10. I've heard that the Powerlinc is an excellent option.
Some modules contain onboard memory. This allows those without a dedicated computer to store timers directly on the interface. Since Power Home doesn't support saving things to onboard memory, I won't bother going into it.
If you choose to go with Activehome for your control software, you'll be using the CM15a, a USB interface.
Unfortunately, Power Home doesn't currently support the CM15a. Since I started with Activehome and upgraded to Power Home, I had to find a workaround--the Firecracker.
The Firecracker (cm17a) is a little device that plugs into a serial port. It sends x10 RF signals, which the cm15a picks up and sends through the powerlines. The cm17a can't recieve signals, but for about $12 it's a good stopgap solution if you start with Activehome and upgrade.
X10 works using a series of modules. Each module allows you to remote-control a different kind of device. Some modules offer 2 way communication, while others simply recieve commands. In order to connect a device to your system, all you have to do it install or plug in the right kind of module. Here is an overview of the basic types.
allow you to control incandescent lightbulbs. You plug the module into an outlet, then plug the lamp or light fixture into the module. Lamp modules can be dimmed, but they can only handle a certain load, so you shouldn't use them for appliances.
A variant on the lamp module is the Socket Rocket.
It screws directly into a light socket and performs the same functions as Lamp Module.
When it comes to local control, both modules are problematic. With both, you can still operate the light using its switch, but the system won't know if you turn a light on, and it sometimes takes several flicks of the switch. For this reason, it's best to use lamp modules only when you won't need to control the device using its own switch.
act just like lamp modules, except they handle bigger loads, and they aren't dimmable. They are basically a remote controlled relay, so they make a distinctive "clunk" when triggered. The same issues with local control apply.
modules replace an existing wall switch. Since they use the same switch cover and wiring as the old switch, they are relatively unobtrusive and easy to install. As modules go, these are some of the most versatile--they allow built in light fixtures in your home to be controlled remotely, while leaving local control uncompromised.
There are a lot of variations on the basic design--companies offer 3 way switches, switches with dimmers built in, etc. For details on installing these swtiches, see the Installing Modules section.
These motion sensors act slightly differently from other modules. They are wireless, so rather than sending signals through the powerlines, they send them through the air, where they are received and relayed by the interface. This allows you to place the sensors wherever you want--some are even waterproof. Eagle Eye
is the X10 brand name for these sensors.
Like motion sensors, remote switches
transmit x10 signals through the air. That, combined with the fact that they're extremely thin, means you can place them anywhere. It's a great alternative to drilling holes and running wires if you need to install a new switch.
are great for tinkerers and DIYers. They have two contacts that are switched when the module recieves a command. The contacts can handle up to 24v, and they can operate as normally open or normally closed. Additionally, the module can switch the contacts for 5 seconds, or leave them switched on until an off command is recieved. Universal modules can be used to automate everything from electonic drapes to garage door openers--I even use one to control my furnace.
In addition to the basic control hardware, it's often useful to add other hardware, like sensors, cameras, etc. into your system. These kinds of hardware are covered in more detail on other pages of the site.