Home API : Innovations in Home Automation Integration.

By Steven Totolo and Franca Piccin

Launched in October 1998, the Home API Working Group is an industry initiative providing an open specification for defining a standard set of software services and application programming interfaces, or APIs. These APIs allow consumer electronics and home appliances to be monitored and controlled by computer applications. Six of the most prominent technology manufacturers involved in this initiative are Microsoft,Honeywell, Intel,Mitsubishi Electric, Compaq Computer, and Philips Electronics. They expect that the APIs will be protocol and network media independent and will function with new and existing home network technologies such as X-10, CEBus, Lonworks,HomeRF, Home PNA and HAVi.

To support developers, the Working Group will release a Software Developers Kit (SDK) that will implement Home API using the Microsoft Windows operating system (OS). This will occur during the first half of 1999. Standard development tools and programming languages such as C++, Java, Visual Basic, VB Script and Java Script can be used to create applications. Developers expect to roll-out consumer products by the year 2000. While SDKs for other OSs are planned, their release dates have not yet been determined.

Despite these developments, there appears to be some compatibility issues with a network protocol known as Jini. Jini is an interoperability framework for Java-enabled devices on an IP-based network. While Home API will be capable of interfacing with Jini devices, this capability will be limited due to design differences. Where Jini requires all devices to speak the same Java-based protocol, Home API is based on a centralized control model. In this model, a few general-purpose intelligent nodes control numerous other devices across multiple home network protocols. This feature provides a way to integrate simpler devices that use different protocols into a unified control environment. While Home API devices will be able to communicate with those of Jini's, the reverse appears not to be the case, thus requiring the use of a bridging mechanism between the two.

Using the SDK, developers will create applications for users to integrate and control an array of home electronics such as televisions, VCRs, indoor/outdoor lighting and temperature control systems. For example, a home theater can be configured to set the lighting level of the room, turn on the television, start up the VCR and adjust the room temperature for a delightful night home "at the movies" by simply issuing a single command.

"Control of multiple home devices is a natural extension of the computing power that consumers have brought into their homes", said Ed Arrington, manager of Intel Architecture Lab's Anywhere in the Home initiative. "Home API will stimulate the development of hundreds of new applications that integrate those devices in a way that adds real value to family and home life. This is a great opportunity for the growth of automation in the home."

Home API will enable applications to control and receive state change events from devices such as motion detectors, light switches, and thermostats. Applications will be able to discern and integrate user interface components to a new level of functionality. For instance, this would enable a television remote control to turn off lights or close drapes in a home theater.

"We believe the establishment of an API specification for PC-controlled home devices will usher in a whole new industry resulting in the unprecedented control of residential environments", said Deb Massof , vice president of Home Vision, Honeywell Home and Building Control. "For example, with Home API technology, manufacturers can offer users products that will allow them much greater control over their home environment, both locally and remotely."

Recently, the growth in the number of home automation standards has made integrating products from different manufactures and network protocols difficult if not virtually impossible. Home API will provide a common layer of functionality above present and future network protocols, lessening integration problems. As illustrated in the figure below, new device types can be defined and additional properties easily added to support custom features, new devices, and protocols.

Home API's first members' conference will be held at Intel's Jones Farm Conference Center in Hillsboro, Oregon in January 1999. New participating members will be brought up to speed on the technical aspects of the application programming model, service provider interfaces, and device models of the specification. More information is likely to be announced by Mike Paull, Microsoft's Managing Director of Intelligent Home Systems Development as he delivers the opening keynote address at the Home Automation Association's 1999 Home Automation Show & Conference in Orlando Florida on February 6, 1999.

This protocol and others are documented and updated regularly in the CABA Quarterly and in the CABA Standards Committee that meets quarterly to discuss issues that affect the business of members in the automation industry. The committee is open to all CABA members interested in up-to date issues involving communications standards, wiring practices, and regulations.

Steven Totolo is president of tvcAutomation, a home automation specialist and a member of the CABA Standards Committee. He can be reached at (613) 795-7117; fax (613) 737-5323; email: sales@tvcAutomation.com