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Designers address challenge of full-feature, low-cost home security

Posted: 05 Mar 2007 ?? ?Print Version ?Bookmark and Share

Keywords:home security?

By RC Cofer and John Schippanoski

Today's homeowners have become accustomed to easy-to-use, multimedia color interfaces, high levels of functionality and performance, and decreasing ownership cost. They have been influenced by their interaction with personal computers, laptops, cellphones, PDAs and portable game units. Users' experiences with those products, and their level of comfort and satisfaction with those appliances, have led to higher expectations and standards for the systems they use. Many installed residential security systems do not meet these elevated expectations, especially when compared with their owner's mobile equipment.

This trend has combined with an increased awareness of vulnerability and desire for personal safety and security to encourage the development of affordable, full-feature, multimedia home security, monitoring and control systems.

Homeowners, of course, expect a security system to be able to detect intrusion and sound an alarm when a system sensor is activated. However, many people would also like to see who is at their door before they open it, or perhaps be able to view who rang their doorbell while they were in another part of their home or out running errands. This ability to access, control and monitor systems around the house is an area that new systems being developed can support.

The challenge for system designers is to implement the required functionality in a low-cost, full-function unit that can be scaled to offer a range of unit functionality at price points that can accommodate the range of potential customer needs and budgets. The design team is also faced with the challenge of getting their products developed, tested and into production as quickly as possible at the lowest possible cost in order to gain market advantage.

The architecture of a price-sensitive application is based on the use of low-cost, highly integrated components. However, with the addition of new capabilities, such as networked communication, complex control functions and video capability, high performance is also required.

The block diagram below, showing a full-feature, low-cost security system, includes a Quarter VGA LCD, Ethernet port for networking, local sensor and control function interface lines, input for an access door video source, and local and remote microphone and speaker pairs. The system also includes a memory expansion socket that can support the loading of user customization files and system software updates into the unit and the transfer of video out of the unit.

This design is based on Analog Devices' ADSP-536 Blackfin processor with an embedded Ethernet MAC block. This system architecture has many advantages. It is scalable and can be networked.

The Blackfin processor family members are code-compatible, and some devices are footprint compatible. This allows the manufacturer to develop units with a range of unit functionality, performance and price points all based on a common modular system architecture.

With this system, users have the ability to remotely monitor video views of their property. Users can also review video captured as a result of customizable system events, such as the front doorbell ringing or activity on a system motion detector. Units with advanced features can also be developed that can interface with, monitor and control home heating and cooling systems as well as control household lighting and appliances through a variety of open standard and proprietary home networking protocols.

Many security-conscious homeowners have been waiting for the arrival of affordable next-generation networked residential security and monitoring systems that provide them the same level of functionality, performance and convenience they have come to expect from their personal communication, productivity and entertainment systems. With new systems currently in development, their wait might soon come to an end.

About the authors
RC Cofer
is an FAE for Avnet's Central Florida office. He holds a master's degree in electrical engineering from the University of Florida.

John Schippanoski is a senior FAE for Avnet working in Toronto. He graduated from Conestoga College, where he studied electronic engineering technology and computer systems. Comments may be sent to

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