|Integrated home automation
systems have been on the market since the early 1980’s but during
the last few years their lower cost and ease of operation and installation
have made them very attractive for installation in middle income homes.
The sudden increase in Ethernet based home networks and Ethernet enabled
devices in only the last two years promises to make home automation
systems even more affordable, useful, and easy to use.
Terms and Definitions
Whole-house automation system – a system that integrates the
operation of various subsystems of the house through a common user
interface. In this section the term “home automation system”
and “whole-house automation system” are used to mean the
same thing. The term “system” implies an integrated controller,
either dedicated to home automation tasks or part of a PC.
Event – An event (as in “event driven”) is
something that can be defined in a HA system to trigger an action.
Typical events are 8:15 AM (time of day), security system armed,
front door open, motion sensor activity, an X10 command, and so
on. Usually, anything that can be monitored by the HA system can
be used as an event.
Program – All HA systems can be programmed to perform various
subsystem tasks based on events or user requests. The term does
not refer to program code written in C+ or a traditional programming
language used to run the system. HA programs (referred to as automation
programs) are proprietary sets of instructions entered into the
system by the installer or homeowner and are unique to each manufacturer.
Some systems use a purely graphical technique of “programming”,
while some manufacturers use a sort of pseudo-code such as:
outside_light = ON
- A scene is a preset list of operating modes defined in
a home automation system of all the subsystems in the house for
a specific event or activity of the house. Typical scenes include
“good morning”, “at work”, “arrive
home”, “evening”, “sleeping”, “party”,
and so on. The parameters that define a scene are programmed into
the HA system by the installer or homeowner and are triggered by
an event such as a time of day. A “good morning” scene
may be triggered by a time of day such as 7:00 AM and cause the
HA system to turn off outside lights, disarm the security system,
turn on the front lawn sprinklers for 20 minutes, turn on the coffee
maker, and so on.
Home Automation Systems
There are two general categories of home automation systems: hardware-based
systems that use a dedicated micro-controller hardware platform or
“controller”; and software-based systems that rely on
a PC as the controller.
Hardware- based systems will use a dedicated hardware controller and I/O electronics,
typically housed in an enclosure with power supply and backup battery.
They will always be supplied with several dedicated user interface
devices and optionally can use PC’s, telephones, PDA, etc.
as a user interface. The main advantage of hardware-based automation
systems is their inherent stability. The hardware is dedicated to
the task of automation and does not rely on a Windows operating
system or other software components on the same machine. Since these
products also handle traditional security system functions, they
are equipped with battery backup and can be monitored by a security
monitoring service. The disadvantage is the reliance on a single
manufacturer for hardware and software support.
Software- based systems operate on a PC running a version of Microsoft
Windows. These systems rely on the hardware capabilities of the
PC and are limited to the I/O capabilities of the PC. Most software-based
home automation products rely on the existence of a network in the
home, typically Ethernet with TCP/IP enabled devices. Software home
automation products are usually supplied with some interface hardware
for the PC such as an X10 PLC serial interface, RS-232 interface,
or Ethernet adapter. The PC is always the primary user interface.
The advantage of software-based automation products is the fact
that they run on a PC, a relatively inexpensive hardware platform
and can take advantage of the large storage and processing capability
of the PC. Hardware support for the system can be obtained from
multiple sources anywhere almost any time. They can usually interface
with several different manufacturers of subsystem products such
as thermostats and security systems using a home network. The primary
disadvantage is the inherent instability. Even if a PC can be dedicated
to running the home automation software, long term stability of
the system is questionable regardless of the Windows operating system
used. These system must also rely on other hardware such as security
systems and lighting controllers to perform those subsystem functions
since the required hardware is not part of the PC.
Home Automation Systems
A typical hardware-based Home Automation System is shown in Figure
5.1. The system consists of a controller housed in a metal enclosure.
The enclosure is similar to those used for security systems and
can optionally be locked. This is because the controller also incorporates
the functions of a security system for the home and therefore should
be protected from tampering. The electronics will have screw terminals
for connecting traditional security sensors and alarm devices, and
optionally other connectors for RS-232, Ethernet, wiring for thermostats,
and an X10 interface to the power line.
Typical hardware-based home automation system
from HAI. The photo shows the controller with two
types of dedicated user interface devices (center, right) and a
The following is a typical set of features for a medium size hardware-based
home automation system .
• Can control hundreds of lights via X10 PLC or hardwired
networked light switches
Control of up to 64 thermostats
Two-way X10 transmission to receive signals for use as program triggers.
It incorporates collision detection and message
retry for reliability
Lights can be set to scenes of varying brightness, with direct dim
and scene support for advanced home theater lighting
Lights, control outputs, temperature and security modes can be scheduled
by time, sunrise, sunset and date or day of week
and various system events
1,500 lines of non-volatile program storage
Programmable via keypads or from a PC
Text and voice descriptions for all zones, units, codes, temperatures,
messages and areas
500+ word speech vocabulary plus user-recordable phrases
Ethernet port built-in for connection to home network
• 16 security zones, expandable to 176
All zones support 4-wire smoke detectors; zones 1-4 support 2-wire
8 hardwire outputs, expandable to 136
Supports 16 LCD keypad consoles
True partitions: security and automation can be portioned into 8
99 user access codes with selectable authority levels
Will turn all lights on when alarm is tripped to frighten intruders
Outdoor lights are flashed when alarm is tripped to alert neighbors
System announces type and location of alarm with optional 2-way
Trouble conditions indicated in English on display for: zone and
system trouble, AC power off, battery low and phone
Phone line monitor
Optional wireless receiver is fully supervised for complete reliability
Dials up to 8 user-programmable numbers and reports type and location
• Works with touchstone phones inside or away from the premises
with access codes
Compatible with answering machines and answering services
From any phone you can change modes, change temperatures, arm/disarm
security, bypass and restore zones and much more
Software-based Home Automation Systems
Software-based home automation system are usually furnished with
a software CD and optionally network or serial interface hardware
(Figure 5.4). Each manufacturer will have specific PC hardware and
software requirements in order to run the system.
is best to dedicate a PC to run the software since it will not only
take up considerable memory and I/O resources on the PC but running
other software and peripheral devices can compromise the stability
of the system.
Premise Systems SYS home automation software
with optional Lantronix “single device server”.
The server allows SYS software to communicate with any RS232/485
device from an Ethernet network.
Software home automation products use
either a proprietary user interface (UI) on the PC or rely on an
HTML formatted web oriented user interface. If the PC is on a TPC/IP
network, an HTML based UI can be accessed on any web enabled device
inside or from outside the home.
Software/PC based automation systems
can perform most of the automation features of a hardware-based
products since they can interface to the power line for X10 control
and use a serial or Ethernet interface to access other hardware
based subsystems. They do not, however, incorporate security system
functions but can usually interface with one or more specific models
of home security systems via X10, RS232, or Ethernet.
Software-based home automation software runs
on a PC and relies on the serial and
Ethernet interface ports of the PC to access other subsystems in
automation systems rely completely on the screen/keyboard user interface
of the PC. Systems which use an HTML web browser interface (Figure
5.6) can also be accessed by any web browser enabled device on the
same home network or from the Internet with a properly configured
programmed UI screen from Premise Systems’ SYS software. The
image from the front-door was
acquired from an Ethernet enabled camera over the home Ethernet
design of the UI can be customized to the needs and desires of the
homeowner by using any web page design software. Different interface
designs can be selected by using a different “home”
page to access the system. Anything that can be done on a web page
(animation, music, video) can be incorporated into a UI for the
User Interface Options
The user interface is the most important component of a home automation
system since its primary function is to provide a common, easy to
use, interface for all subsystems in the home. For that reason,
the user interface is also the major differentiator between manufacturers
and a key factor in selection of a system. With the increase in
wired and wireless home network technology and high-speed Internet
access, the user interface options have increase substantially.
home automation systems will have several types of user interfaces
available that can be used at the same time. The major categories
of user interface (UI) are the keypad, telephone, PC, web devices,
The keypad device, also referred to as a console, (Figure 5.7) is
the oldest and most common UI device and used exclusively by hardware-based
home automation systems. They are usually wired directly to the
controller with low-voltage cable and are powered from the controller.
Keypad/display devices come in an infinite variety from simple LED
lights and two or three buttons, to graphical LCD displays with
full alpha-numeric keypads. The most common are two or three line
LCD displays with numeric and special function keys (see Figure
5.7). When the home automation system is the security system, keypads
provide a traditional UI for security system functions and are typically
installed where a security keypad would be placed.
keypad user interface for a home automation system. The display
and buttons are backlit for easy use at night.
The touch-tone telephone has been used as a UI for home automation
systems since the 1980’s. Most hardware-based home automation
systems and several software-based system (with appropriate hardware
sound I/O interface) allow the use of a phone (either traditional
wired or cell) to access the system for status and control functions.
The phone keypad is used in a “voice-mail” fashion to
select from a series of menus spoken by voice output from the HA
This provides a very convenient UI
since there are usually several phones around the house as well
as portable phones. The phone interface can also be used from outside
the house from a cell phone by inputting a security access code.
A home PC can be used as a user interface for most hardware-based
home automation systems usually running application software provided
by the manufacturer. Connection is typically through the serial
port on the PC wired directly to the home automation system controller.
As the PC interface migrated to more traditional PC networks such
as Ethernet, the interface has also migrated to using a standard
web browser (client).
Wireless user interface access to HAI’s
home automation system is made possible by low cost PDAs and 802.11b
hardware. The same device can be used from any wireless network
in the world that has Internet access.
The latest trend in home automation system user interface design
is to install a web server in the system controller and use a web
browser client to access the system through a home network. The
advantage of this approach is that it allows the homeowner to use
any web enabled device such as a PC, PDA, or web tablet to access
the system (see Figure 5.8). Since the cost of web enabled devices
is constantly falling, this is an attractive alternative to expensive
proprietary graphical displays.
software in the home automation system must be designed to present
the system information and menu screens in an HTML format. If the
home network is attached to the internet via a router, then the
homeowner can access the home automation system from anywhere in
the world via the Internet. The router must be configured to allow
access to the home automation system from the outside the home LAN.
UI technique is used by most software-based home automation system
products that run on a PC. The home automation software has a web
server as part of its design. Many software-based systems also allow
the installer or homeowner to customize the look and feel of the
web page design.
Typical UI screen for HAI Omni Pro automation
system Web-Link software component. The screen is accessed by entering
local IP address of the networked HA system (for example http://192.168.100.148)
using any web browser
Automation System Operation
While a home automation system can be used to perform isolated tasks
(such as turn on a light or set the thermostat) its biggest benefit
is coordinating the operation of subsystems based on how the homeowner
wishes the house to operate at different times of day or different
events. The subsystems in the house are usually set a specific way
during these events, and the entire set became known as a “scene”
A “scene” is like an operating mode of a house and is
a key concept in home automation. The term comes from the stage
setup in a play. A scene is a preset list of operating modes of
all the subsystems in the house for a specific activity of the house.
Typical scenes include “good morning”, “at work”,
“arrive home”, “evening”, “sleeping”,
“party”, and so on. For example, a scene such as “arrive
home” may be how the homeowner wants the house to operate
when the family arrives home from work or school. This might be
defined as: security system disarmed, certain lights on, other lights
off, temperature at 72, music system to a favorite CD, music in
the family room, kitchen, den, check for e-mail, and so on.
A home automation system usually has
several common scenes pre-programmed (such as “home”,
“away”, “asleep”) while others are defined
by the homeowner and typically programmed by the installer. Not
all operations of a HA system need to be part of a scene.
All HA systems perform monitoring and
control operations through a combination of three types of events:
Preprogrammed and timed schedules -
operations such as turning lights on or off, arming a security system,
turning on the sprinklers, or setting the house to a scene can be
set to occur at specific times on specific days. These schedules
can be entered and adjusted by the homeowner or by the installer.
driven - operations such as turning lights on or off or
setting back the thermostat can occur based on some event such as
a motion sensor input, a temperature change, or someone ringing
the front door bell. The programming of what event causes what action
is typically set by the installer after conferring with the homeowner.
However, some systems provide an easy to use interface, typically
on a PC, to allow the homeowner to program events.
selected - actions and scenes can be initiated directly
by manual user input such as pressing a keypad button labeled “night
scene” or a similar button on a remote control.
Associating an event with an action is done through an automation
program entered in the system by the installer or homeowner. Programs
use a simple programming like “language” to identify
events and actions to take when the event (or group of events) is
true. Typical examples might be:
SECURITY = ALARM
OUTSIDE LIGHTS = FLASH
TIME = 11:00 PM
THERMOSTAT (ZONE 2) = 71
first program will cause the outside lights to flash on and off
if the security system is in the alarm condition. The second program
will set the zone 2 thermostat to 71 degrees at 11:00 PM. The HA
system constantly interprets the programs to see if the IF condition
is meet in the program and if so, performs the THEN action.
entering the program, key words such as IF, THEN, THERMOSTAT are
usually selected from menus to make it easier and quicker. Improper
syntax mistakes are detected and flagged before they are entered
into the system. Most HA systems can typically store hundreds of
automation programs requires care and practice with each system
since it is easy to enter conflicting programs that can have unpredictable
results and confuse the homeowner.
The home automation system controller contains the electronics of
the system (micro controller, memory, sensor interfaces, alarm device
interface, monitoring service interface), power supply, and backup
battery. Most controllers are contained in a lockable steel box
mounted on the wall and contain no "user serviceable parts".
The panel is located in a conditioned space of the home. Since the
controller performs all the functions of a security system it should
be accessible but not easily locatable by an intruder. Typical locations
include a closet, basement, or utility room.
Typical home automation system controller
security systems, HA controllers usually have a battery power backup
installed in the enclosure. Most manufacturers provide additional
expansion boards and electronics to increase the number of I/O devices
that can be attached to the system (see below).
controller is usually available separately mounted on a bracket
to allow it to be mounted in a structured cabling system enclosure.
This makes a very convenient installation since the controller should
be in the same location as the structure cabling system to access
network wiring, telephone service wiring, and security device wiring.
A variety of expansion modules are available for hardware-based
HA system to allow adding security zones, monitored contact closure
inputs, relay contact outputs, and various analog inputs and outputs.
are also available to add special features such as an Ethernet interface,
X10 I/O, thermostat interfaces, and so on.
I/O expansion board. The board is supplied with cable and
mounting hardware to attach it to the main controller board.
Installing a hardware-based HA system is only slightly more difficult
than installing a conventional security system. The additional work
includes connection to other peripheral devices such as thermostats,
networked light switches, consoles, etc.
Since hardware-based systems incorporate
security system functions and devices you may need to obtain a state
security/low-voltage license. Check with your local city or country
government offices to determine if you are required to have a license
in your area.
All of the installation information
in Section 4 is applicable since installation usually requires installing
many of the subsystem devices to automate the home.
HA system controllers are usually installed
next to or as part of a structured cabling system since this allows
all the cabling to be run to the same location. The controllers
can often be mounted in the same enclosure as the structured cabling
system, simplifying the installation and greatly reducing the wall
Whole house automation system will require some integration tasks
to interface the system with existing products and subsystems in
the house. There are two basic ways to accomplish integration. Remove
existing devices in a subsystem and replace them with home automation
“friendly” devices that will interface easily, or use
existing equipment by installing adapters, converters, or interfaces
between the equipment and the home automation system.
example, to interface to an existing HVAC system using the first
technique, the non-automation thermostat is replaced with a thermostat,
such as the one shown in Figure 5.2, supplied with the home automation
system that is either hardwired to the automation controller or
communicates with the controller over a home network. The “home
automation thermostat” then acts as a subsystem interface
between the HA system and the HVAC subsystem.
Once a system is installed it must be configured for the home environment.
This includes entering occupant information, room and device names,
zone information, access codes as well as scene and automation program
information. While this can be done using keypads/consoles, most
hardware-based systems allow the use of a laptop PC running either
a browser program or a manufacturer supplied access program. The
PC can be attached locally in the home or, on some system, can use
a modem and dial into the system from a remote location.
Configuration software is naturally built-in to
software-based products since they already run on a PC. They simply
use setup or configuration screens.
is complete all information entered can be stored in a separate
file on the configuration PC or the PC running the software-based
system. If a system needs repair or replacement, the file can be
downloaded back in to the system from the PC configuration software.
Sample screen from PC Access software used
to configure HAI’s home automation systems.
Configuration software also allows you to monitor the present status
of all system components, including door and window sensors, lights,
appliances, thermostats, I/O expansion boards and other internal
and external components.
Most systems also keep an “event
log” that stores a record of all status changes and each action
taken by the HA system. This can be downloaded and examined by the
configuration software (either locally, through a dial-up connection,
or over the Internet). This is a great troubleshooting tool to locate
malfunctioning sensors, bugs in automation programs, and improper
operation by the owner.