What is INSTEON Technology?
A staple of consumer automation applications, INSTEON technology is the brainchild of homeimprovement company Smarthome, notable for a wide range of remote-control products. The technology builds upon and is compatible with existing X10 products and networks, while providing greater reliability, flexibility, ease of installation and use, and all at a lower cost.
Simply put, INSTEON technology is a dual-band mesh topology employing ac-power lines and a radio-frequency (RF) protocol to communicate with and automate home electronic devices and appliances, which normally work independently. A typical end-user network consists of plug-in, wired-in, and battery-powered modules that are set up via a PC or dedicated controller using plug-and-tap technology (see Figure 1).
Each device has its own unique ID, eliminating the need to set addresses or manipulate code wheels. Linking two devices is as simple as pressing and holding the ON button on the first controller device for 10 seconds, then doing the same on the second device.
Upon installation, the components form a peer-to-peer, unsupervised network requiring no routing tables. Sending and receiving communications either wirelessly or over the power lines, each device acts as a repeater capable of resending commands should they be corrupted or dropped. The result is a system that responds with imperceptible delays and becomes more reliable as it expands.
On the design side, the technology also involves software, USB and RS-232 connectivity, with Ethernet capabilities for interfacing to a LAN and the Internet on the not-too-distant horizon. Development kits and a prototyping module are available, which include membership in the INSTEON development alliance and provide access to the development forum. A full set of development support services, including e-mail and telephone consultation, are also in the mix.
Differing from X10 and other home-automation designs, the formation of a peerto-peer network allows all INSTEON devices to perform as a controller, responder,or repeater, sending, receiving, or relaying messages, respectively. For example, one module acting as a controller can send messages to multiple responders, or several devices can act as controllers sending commands to a singular responder (see Figure 2). Just about any combination, depending on the function, is possible.
Providing that layer of reliability, any component can repeat messages, relaying information from device to device (see Figure 3). Of course, this applies strictly to INSTEON signals; modules can send and receive X10 signals over the power lines, but will not repeat and/or amplify them.
Accented highly is the concept that an INSTEON network's reliability increases as the number of devices increases. Each component can repeat messages, doing so automatically upon power up without the tedium of unique installation techniques or special setup procedures. In practice, the more devices on the network, the more message pathways are available (see Figure 4). With multiple paths, the probability that a signal will find its target is more likely.
Theoretically sound, this concept could imply that the designer needs to glut a system with devices to insure total reliability, which appears not to be the case. Better put, an INSTEON network will retain its integrity either as it expands or in its accommodation of larger installations with challenging layouts. More devices may address line-of-site issues on the RF side or bring more sophisticated control to upper and lower floors on the power lines. Again, the more signal paths the better.
How It WORKS
Reliability in an INSTEON network stems from redundant signal paths: power lines and RF. On the power line, all messages synchronize to the ac zero crossing via a 131.65-kHz carrier signal. Other than source and destination code, the messages are of fixed length and contain no other routing information. With standard and extended message sizes of 10 and 24 bytes, respectively, the network provides instantaneous data rates up to13.165 kb/s and sustained speeds to 2.88 kb/s.
Each device in the system receives a unique ID, of which there are 16,777,216. Support is available for up to 65,536 device types and up to 256 groups per device. There is no limit to the number of members within a group except memory: basic requirements for the INSTEON engine are 80 bytes of RAM and 3 KB of ROM. A typical application involving basic light switching and dimming requires 256 bytes of RAM, 256 bytes of EEPROM, and 7 KB of flash memory.
Furthermore, the power-line protocol employs bi-phase shift keying (BPSK) modulation and specifies a minimum transmit level of 3.16 Vp-p into a 3½ load. Minimum receive level is 10 mV. Phase-bridging functions fall into the hands of hardware or the RF protocol. Relying on frequency shift keying (FSK) modulation, the RF protocol operates in the 904-MHz band. This topology yields a sensitivity of -103 dBm and supports communications at distance up to 150 ft., assuming and unobstructed line-of-site environment. Again, each device in the network acts as a repeater, so operating distance increases proportionately as the system expands.
A North American type system will employ both sides of the power line, which splits at the home's junction box into a pair of two-wire, 110-Vac lines: Phase 1 and Phase 2. One half of the network resides on the Phase 1 line, the other half on Phase 2 (see Figure 5). With the exception of any X10 devices and the PC or controller, all communications over the network are via RF, the power lines, or a combination thereof.
Developed in 1975 by Pico Electronics of Glenrothes, Scotland and considered an industry standard for home automation, X10 sends short RF bursts representing digital information over power lines. Although RF is part of the design, communication is purely over the power line and not over the air. Employing a higher bandwidth, INSTEON products support X10 on the power line only. They send and receive X10 commands, but do not repeat or amplify X10 signals. This support merely allows designers to create hybrid networks that operate well in both environments, accommodating painless upgrades without obsolescing users' investments in X10.
Although considered viable competitors, it is difficult to compare the likes of ZWave, ZigBee, Bluetooth, Wi-Fi, Home-Plug, Universal Powerline Bus (UPB), and high-speed power-line protocols to INSTEON's dual-band networks. Each having its niche market, the majority of these technologies use a single-band approach, power line or RF, and, reportedly, not all focus purely on automation applications. Be that as it may, INSTEON makes the comparison by pointing out ZWave and ZigBee as requiring extremely complex routing strategies, Bluetooth is short on range, Wi-Fi and UPB as being too expensive, and X10 lacking in flexibility and reliability.
Back in January at CES 2006, Smart-Labs, the third subsidiary of the SmartHome triad, unveiled a wire-line modem IC as the first member of a family of INSTEON chips and also announced a soon to be available RF modem. The devices sound a prelude to further connectivity via the Internet and home Intranets. Prices are set at $1.60 and $2.90 each for the wire-line and RF modems, respectively, with no minimum quantity.
Also at CES, home-automation software-developer Perceptive Automation and voice-control software specialist Home Automated Living hopped on the bandwagon with support for and management applications employing the INSTEON protocol. Developers such as these can license the technology at no cost, opening the field for further support and innovation.
Lastly, the first INSTEON developersand-technology conference will run concurrently with the CONNECTIONS conference-in May at the Santa Clara Convention-Center. The event will be open to current and prospective developers as well as those seeking more information about the technology. Visitors can expect to see demonstrations of products under development from partner companies and hear about emerging technology insights and unique applications. On the business side, there will be examples and data regarding current and future market opportunities.
Prototyping module: http://www.smarthome.com/insteon/hdk2610.html
SMARTLABS INC., Irvine, CA. (800) 762-7846.
PERCEPTIVE AUTOMATION LLC
HOME AUTOMATED LIVING, Laurel, MD.. (800) 935-5313.
Company: SMARTLABS INC.
Product URL: Click here for more information