Technology Showcase: Handheld Device Integration
Aug 1, 2008 12:00 PM, By Bennett Liles
Remote controls enter a new phase.
One need look no further than the nearest living-room coffee table to find one of the most revolutionary devices to impact modern communication: the remote control. Those of us old enough to remember television before the wireless TV remote might vaguely recall how when the TV was set on one of the few channels available, it stayed there — and we pretty much watched what the local station gave us, rather than jumping up and crossing the room to turn the knob and adjust the antenna.
That tiny little box with the buttons heralded a new age — not only in narrowing viewers' activity and expanding their waistlines, but in the way everything on television is marketed. Now we can zap away commercials in an infrared flash and fully indulge our shortest attention span.
Virtually every AV system that is conceived today is built around mobile handheld control to some extent. Spurred by new transmission technologies, more options have come online for increased distance and more automation. Now it has become a huge field with hundreds of companies marketing handheld control devices along a wide spectrum of sophistication and cost. While these are far too numerous to mention individually in this article, we will have a look at some typical examples of handheld AV control devices and examine the various transmission methods used to extend control to the central components of some modern AV systems.
Based on the IEEE 802.15.4 protocol, ZigBee is a widely used and robust transmission scheme that provides a low-power, short-range control solution for personal area networks. Its advantage over wireless USB and Bluetooth is that it can form a mesh network between nodes by daisy-chaining from one device to another, allowing its range to be easily expanded. ZigBee's limited bandwidth of less than 100kbps is not a problem at all for handheld control devices because their traffic load is very light, sending an occasional control command and getting a single-device feedback response. The program material from the controlled device is not using the control link, so any higher-speed conveyance is not necessary. Typically, the data stream is much slower than that used by the average computer keyboard. There are various categories of ZigBee devices. The ZigBee network coordinator is a smart node that automatically initiates the formation of the meshed network. A ZigBee router is a smart node that links groups together and, through association with other routers and end devices, provides multi-hopping for control data streams. ZigBee end devices may be individual sensors, actuators, monitors, switchers, dimmers, and other activation devices.
Some of the latest handheld control devices have maintained the general form of the TV remote. After all, for some applications, why abandon the profile that has worked so well for millions of users over the years? But many of these have added display screens, in large part to offer the feedback from controlled devices afforded by two-way communication protocols in wide use. Such is the case with the AMX Mio Modero R-4 remote. The R-4 has a full-color, backlit 2.4in. active matrix TFT with 240×320-pixel resolution, a 60-degree viewing angle in all directions, 16-bit color depth, and a 300:1 contrast ratio. Twenty-nine hard buttons and two LCD buttons operate an unlimited number of devices connected to an AMX control system. The 100ft. RF transmission range is extendable using AMX NetLinx repeaters. The display shows device status feedback, dynamic lists, movie titles, and song selections received using the ZigBee two-way communication. The circular navigation ring provides menu navigation and item selection common on many remotes.
In the realm of handheld AV control, there are two basic technical philosophies. The first makes use of more generic control protocols integrated at some point into the system being controlled, the thrust being that a somewhat higher degree of customization and more universal integration are possible. The trade-off is normally the fact that this requires some training in how to use a specific software application for initial configuration and to accommodate changes in makes and models of AV equipment due to the fact that these will require specific drivers. Many commercial systems that offer handheld control device integration are set up this way as are the more top-end home systems. After all, many of the commercial, more sophisticated, and expensive home AV control systems are made by the same manufacturers and use the same configuration software. The other tack includes systems that are configured to operate around a central server and can include modular hardware additions to suit specific tastes and conditions. The basic approach relies on hardware controls with specific functions to offer simplicity and a faster learning curve.
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