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Home automation system gains Linux-based controller

Mar 27, 2008 — by Eric Brown — from the LinuxDevices Archive — 112 views

[Updated Mar. 29] — Control4 has added to its line of Linux-based, ZigBee-compatible home automation/media networking products with a new controller. The Control4 Home Controller HC-500 interfaces with home theater appliances, multi-room music access, lighting, thermostats, and security systems, and comes… with a Linux software development kit (SDK).

(Click for larger view of the Control4 HC-500)

In a recent ABI Research study on home automation and the ZigBee and Z-Wave short-range wireless technologies, Control4 was singled out for helping bring down the cost of home automation systems. The market has been controlled by luxury vendors such as Creston and AMX, says ABI, which have recently been forced to drop prices.

ABI also found that all of these vendors have been increasingly integrating networked delivery of music, along with automation of lights, temperature, surveillance, and other household functions. “It makes sense to integrate everything in the home with a single system,” said Control4 CTO Eric Smith in an interview. “You shouldn't need to have different systems and different controllers all over the house.”

A “single system” doesn't mean a single device, though. Control4's product line includes a choice of three controllers, a variety of touchpanels, “speaker-point” devices that connect a pair of speakers to the network, media extenders, tuners, amplifiers, and audio switches, all of which run Ubuntu Linux on a Linux 2.6 kernel. The company's smaller keypads and lighting and temperature controls do not run Linux, however.

Control4's Linux-based wireless touchscreen, speaker-point, and multi-channel amp
(Click any to enlarge)

Control4 also resells a Sony DVD changer and video switcher that can be integrated in the system. The latter is said to distribute HD-quality video throughout the house. Most of these devices can be enabled with the ZigBee (802.15.4) mesh-networking wireless technology, and the larger A/V-related systems offer Ethernet connectivity, with several systems also supporting WiFi.

The HC-500 — a versatile media server

The new HC-500 is primarily billed as a media server, intended for large home theaters requiring extensive I/O connections for device control. However, it also coordinates lighting, temperature, video cameras, and manual controls such as blind- and garage-door openers. It's positioned as the mainstream controller choice in between Control4's low-end HC-300 and luxury HC-1000.

HC-500 Controller (rear)
(Click to enlarge)

Based on an undisclosed Texas Instruments DaVinci processor, the HC-500 offers a 160GB hard drive, compared to the HC-1000's 500GB drive and no storage on the HC-300. The HC-500 is equipped with two USB ports, one Ethernet port, four serial ports (DB9), analog and digital audio I/O jacks, and optional WiFi connectivity.

The system can distribute analog audio to three zones, says Control4, and can stream digital audio throughout the house via Ethernet or WiFi. The controller can also control IR, contact, relay, and serial connections throughout the house, says the company.

The HC-500 can be controlled via a graphical interface displayed on a TV or on touchscreens scattered throughout the house. With the addition of the Windows-based Composer Home Edition application, users can customize the system, and also control it remotely via the web. Features include customized playlists and cataloging and selection of digital music by artist, genre, song, or album cover art.

The Composer Home Edition software lets users tie functions together with scripts, Smith said. For example, it could be used to:

  • Customize lighting and dimming
  • Gradually raise or lower temperature
  • Automatically raise blinds with synchronized music playback
  • Turn speakers and TVs on and off
  • Monitor energy usage
  • Monitor video surveillance cameras
  • Receive email notification based on household events, such as a garage door opening.

For more in-depth customization, Control4 provides a Linux-based Control4 Software Development Kit (SDK) that provides programmers with instructions, reference material, code samples, and headers to develop serial-based drivers for home automation devices.

Based on an underlying Director API, the SDK package includes SDKs for Director (which specifies the SOAP interface), DriverWorks (for developing and modifying device drivers), and one for Adobe Flash user interface development. DriverWorks uses the Lua scripting language, says Smith. Coincidentally, a free version of the PHP-like Lua language recently became available as part of a BarracudaDrive release for Linksys's NSLU2 device. Originator Real Time Logic claims Lua server pages to be faster, lighter, and more modular than PHP, while supporting AJAX and other advanced features.

Smith commented, “Director is the brain, and Composer Home Edition is the configuration tool, and with the SDK we allow Lua [modules] to be written, so people can write [control interfaces] for new automation devices.”

As a whole, the provided development tools make it easier to install systems and develop applications than with typical luxury home automation systems, Smith claimed, contending that the latter requires “weeks or months of work from a $200 an hour 'C' programmer.”

The company's goal, said Smith, is to make Director and the related SDK interfaces into a “Novell Netware” of the home automation market. “We have released the Director API to about twenty partners,” said Smith, who said they are now opening it up to the general developer audience. “We're in contract with a consumer electronics manufacturers to use it in their systems.”

The choice of Linux was fairly easy for Control4, said Smith. “Using Linux and open source technology has helped us deliver a higher feature set for a lower price point,” said Smith. “Linux lets us have control of our own destiny, so we can more easily do things that are nonstandard and have access to our own drivers.”

Smith said his company is working on a driver for Z-Wave, which is competing with ZigBee, but he believes that ZigBee will emerge as the dominant short-range wireless technology this year. “ZigBee supports a lot more simultaneous devices and has more bandwidth,” he said. “It's also an open standard, unlike Z-Wave. Open standards tend to emerge more slowly, but unless a giant like Microsoft comes along and backs the industry contender, the open spec usually wins in the end.”


The HC-500 is shipping now, with a list price of $1,500. The Linux-based Control4 Software Development Kit (SDK) costs $2,000, or $2,900 for a “professional” version that includes a media controller and remote control. More information on the SDK may be available here.

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