Home Automation Controlers

This section of the guide will describe the basics of integrated home automation systems. The primary goal of a whole-house automation system is to integrate most if not all of the subsystems of the home together so they work in a coordinated way to enhance the comfort, safety and convenience of the home and to provide a common user interface. Even though separate subsystems may be automated (as described in the previous Sections), a home automation system is required to “pull them together” so that actions in one subsystem can be used to affect the operation of another subsystem.

Home Automation Controlers
Remote Controls

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:

If time=8:30

Then outside_light = ON

Scene - 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.

Typical 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.


Home Automation Controlers
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 thermostat (left).

The following is a typical set of features for a medium size hardware-based home automation system .

Automation Features
• 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 control
• 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

Security Features
• 16 security zones, expandable to 176
• All zones support 4-wire smoke detectors; zones 1-4 support 2-wire smoke detectors
• 8 hardwire outputs, expandable to 136
• Supports 16 LCD keypad consoles
• True partitions: security and automation can be portioned into 8 areas
• 99 user access codes with selectable authority levels
• Will turn all lights on when alarm is tripped to frighten intruders away
• Outdoor lights are flashed when alarm is tripped to alert neighbors and police
• System announces type and location of alarm with optional 2-way voice module
• Trouble conditions indicated in English on display for: zone and system trouble, AC power off, battery low   and phone line dead
• Phone line monitor
• Optional wireless receiver is fully supervised for complete reliability
• Dials up to 8 user-programmable numbers and reports type and location of alarm

Telephone Control Features
• 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.

It 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.

Home Automation Controlers
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 the home.

Software-based 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 home router.


Custom programmed UI screen from Premise Systems
Custom 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 network.


The 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 system.

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.

Most 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, and voice.

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.

Typical keypad user interface
Typical 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 system.

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
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.

Server 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.

This 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 the
local IP address of the networked HA system (for example using any web browser


Home 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.

Event 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.

User 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:








TIME = 11:00 PM



The 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.

When 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 simple programs.

Entering 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 and enclosure.

Like 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).

The 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.

Expansion Modules
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.

Expansion boards are also available to add special features such as an Ethernet interface, X10 I/O, thermostat interfaces, and so on.

I/O expansion board
Typical 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 spaced needed.

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.

For 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.

Once configuration 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.


PC Access 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.

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