The goal of this article is to bring you up to speed on the current offerings in home automation technology. I'll starting by defining what home automation is and then describe the wide variety of systems and protocols available. I'll then finish with some tips for getting started and links to helpful online resources. Let's get to it!
"Home Automation" is a term that is sometimes hard for those who are new to the subject to understand the scope of. However, I think it's easier to explain to those of you who are already familiar with the concepts of home data networking.
When you first decided to build a home network, you probably started with a simple router and a few PCs. Then you probably added other components to that network, such as a file server or a networked printer.
Well, this is exactly how many people approach setting up a home automation network. In fact your home automation network could even be an extension of your existing basic home network (Figure 1).
Figure 1: Example Network
Home automation is nothing more than a network of devices, such as computers, lighting, security, irrigation and home theater systems, that all have a method to communicate with each other. Actions are then performed based on the state of each of those devices.
For example, if you turn on your home theater and push "Play" on a remote, the theater would tell the other devices that this event has taken place. Other devices may then respond by turning off lighting and increasing the temperature in the theater room.
But Home Automation can also be as simple as a "universal" remote control that runs a macro. Every time you turn on your DVD player using the universal remote, the controller can send out a series of IR signals to also turn on your TV and surround sound system. All you have to do is press one button and several actions are performed.
Every family has their own unique needs, which can be as simple as controlling the TV and as complex as knowing where every child is, in and around the house, using RFID and motion sensors. Since I'm sure you can all program a universal remote and this is a networking site, we will be focusing on the more interesting and complex applications.
A home automation network consists of one or more automation controllers and devices that are controlled. Controllers can be anything from a PC running inexpensive software, to a dedicated solid state hardware controller.
The key to a good automation controller is its input and output capabilities, which allow connecting various types of devices as well as its programable logic engine that gives the controller intelligence.
PCs are the most flexible controllers in that they allow you to add additional serial and USB ports as you need them. You can also use third party products for analog and digital inputs for performing measurements such as temperature sensing or monitoring the state of a relay.
Solid state hardware controllers are the most reliable, because they don't have moving parts and therefore don't have mechanical failures like a PC would. Dedicated hardware controllers also consume less energy. Some solid state controllers are extremely flexible and allow you to add additional modules to expand the capabilities of the system.
The remaining parts of your home automation network are made up of just about anything you can think of. Some of the more common components are light switches, thermostats, sprinkler systems, and audio and video equipment, just to name a few.
Typically, each of these devices communicates with the automation controller using one of a few communication mediums. Some may use wireless, while others may be hardwired.
Devices also speak different languages that are typically referred to as their protocol. Just because two devices are wireless does not mean they can talk directly to each other. If they don't speak the same language then you must rely on them talking to the controller and then the controller would talk back to the other device. The controller essentially becomes an intelligent hub.