Appliance Design - October 2007 - (Page 34)

ELECTRONICS Fig. 2. ZigBee implements a self-forming and self-healing mesh network topology. Fig. 3. Example ZigBee SoC (system-onchip) includes processor, Flash memory, MAC, 2.4 GHz radio, and various peripherals. systems and in-home displays to the meters. Thousands of homes have already been equipped with these systems in pilot projects in Texas and California, with rollouts planned for millions of homes starting early next year. During periods of peak demand, utilities use these networks to throttle highload devices in participating homes, such as changing the thermostat setting of the HVAC system. Utilities save in a big way by not having to build new power plants; participants share in the savings through attractive rebates; and communities avoid the ravages of rolling blackouts — the coarsest form of demand response. In other scenarios, utilities may institute “time-of-use” pricing schemes, where the HAN is used to communicate the current price of energy to the consumer. Smart, communicating appliances connected to the HAN can then be set to operate only during low-cost energy periods. The advent of HANs for energy management coincides with the rapidly growing adoption of wireless technologies for home automation and monitoring products that control entertainment, lighting, climate, and security systems in the home. A recent National Association of Home Builders survey projected that whole-house automation will become standard in upscale homes 34 applianceDESIGN October 2007 within seven years, and will make significant inroads even in average homes. And various broadband and wireless telecom service providers are beginning to offer home awareness services that monitor connected home systems over the Internet or cell phones. Whether through government mandate, attractive energy cost savings, or simple convenience, consumer demand for smart, networked appliances is on the way. But is the technology ready? Just as Wi-Fi grew to meet the demand for wireless data networking, and Bluetooth for wireless cell phone connectivity, ZigBee has emerged as the standard for wireless control and automation networks. The ZigBee standard For those not familiar with it, ZigBee is a wireless networking standard designed specifically for highly reliable, low-power, and low-cost control and monitoring applications. Similar to the way Wi-Fi specifications leverage the IEEE 802.11 standards, ZigBee is built on top of IEEE 802.15.4, and enables devices to self-assemble into wireless mesh networks that can operate for years on lowcost batteries. The 15.4 standard defines the physical and MAC layers, typically operating at 250 kbps on one of 16 selectable channels in the 2.4 GHz band, which is uniquely unli- censed in most of the world. ZigBee further specifies a complete and reliable network stack that defines how the mesh network forms and operates, including device association and addressing, routing, security, and management. ZigBee also defines application profiles that specify device types and messages for various applications, such as lighting controls, HVAC controls and so on. The ZigBee standards are specified by the ZigBee Alliance, made up of more than 220 member companies, including many well-known global brands. The Alliance has independent labs which test, verify and certify ZigBee platforms and products for conformance to the specifications, insuring interoperability. (See www.ZigBee.org.) ZigBee is designed to be easy to incorporate into a wide range of devices, and be easily deployable. However, this does not mean ZigBee is a simplistic protocol. In comparison to earlier proprietary solutions aimed at home networking, ZigBee is highly scalable, supporting thousands of devices in a very robust and reliable self-configuring and self-healing mesh network. ZigBee also provides strong security capabilities to prevent mischief, and is extremely tolerant of interference from other radio devices, www.applianceDESIGN.com http://www.ZigBee.org http://www.appliancedesign.com

Table of Contents Feed for the Digital Edition of Appliance Design - October 2007

Contents Editorial Shipments/Forecasts News Watch Applying Powder Coatings to Plastic Parts is No Longer a Pipe Dream New Technology Platform Provides the Ability for a single IC to Control Two- Motors in a Single Appliance, Simplifying Motor Control Design Advanced Motor-Control Techniques have Become More Accessible to a Wider Array of Appliances, Helping to Improve Efficiency and Reduce Noise Adding USB Host Capability to Appliances Permits In-Field Programming and Acquisition of Test Data ZigBee Modules Make it Easier to Design Wireless Connectivity into Applications New Concepts such as Rapid Tooling and Rapid Injection Molding Provide Stepping Stones Between Prototyping and Full Scale Production A Number of Factors and New Developments Affect the Decision on Whether to Build Prototypes In-House or Outsource to a Service Bureau DesignMart Advertiser’s Index Association Report: CEA

Appliance Design - October 2007

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