2013-05-07

3 Routes to Color-Adjustable Home Lighting

Assuming people will ever want to control the details, including the color, of LED lighting in their homes, how should this control be accomplished? Three projects provide different answers.

LEDs enable the creation of lighting products that can be flexibly controlled in ways impossible for traditional lighting. With an incandescent or a CFL, you get on/off, dimming, and possibly three levels of light output -- end of story. The color temperature is whatever it is. It doesn't change except by inadvertence: An aging CFL or a deeply dimmed incandescent may exhibit a color shift, but this behavior is hardly by design.

An LED, of course, can be designed with adjustable lumen output, color temperature, and color over a wide range. Hobbyists, startups, and established companies are busily exploring the possibilities inherent in this flexibility.

The applications for selectable color are many: Among the most obvious are productivity enhancement and influencing mood in workplace and educational settings; mood alteration and direct therapy in healthcare; and plant growth. Whether there is (or will ever be) a large market for color-controllable lighting in the home is still an unanswered question.

(Please take our quick poll and help us decide whether this color-control thing has staying power or not.)

Control
We'll take a look at three attempts to address the (putative) market of people who desire to control their lighting at home in a more complete way, with attention on the means of control these projects implement.

The three projects agree on one thing: the best choice of a remote-control device for controlling home lighting is a portable computing device: a smartphone or tablet. Who could disagree? Most households years ago reached the saturation point for home electronics remote-control devices. No lighting control system is likely to achieve critical mass if it bids to add to the pile of remotes on the coffee table.

Hue (Philips)
Since we last visited Hue in March, with a nod in April, the product won the Judges' Criterion Award at Lightfair 2013. The judges seemed most impressed by the fact that Philips (sponsor of this site) published an application programming interface (API) so that developers could write apps using Hue as a platform.

Hue is controlled using a combination of standard WiFi (802.11) and ZigBee (802.15.4) wireless networks. The Hue starter kit, available at Apple stores and on Amazon.com, includes a WiFi-to-ZigBee bridge that is connected via Ethernet cable to the home's WiFi access point. The bridge takes commands relayed by the access point from the homeowner's iPhone, iPad, or Android device and sends them to individual bulbs over the ZigBee mesh network.

Officially, Hue supports up to 50 bulbs from a single controller. The developers say they have tested up to a few hundred bulbs with no issues.

The app that Philips supplies seems perfectly functional on the iPhone, according to a video review of Hue -- it lets you set brightness, color temperature, and color for each bulb individually, and for ad hoc groups of bulbs. You can also set colors by picking from photographs on the mobile device, and set bulbs to brighten or dim on a schedule. Some reviewers point out the difficulty (or impossibility) of saving settings in the app, including schedules.

The Hue developer program hasn't produced many useful or imaginative apps thus far. Of the handful I found by browsing through the Apple app store, most simply duplicate functionality that the official app already provides.

Hue is far and away the most "real" product in this survey. It has been shipping in volume for a few months now and has the beginnings of an enthusiast community building around it. The price point of around $60 per bulb reflects the state of LED technology circa 2011 or 2012: If the Hue bulb were being designed today it could probably come in below $20 retail, using technology such as Marvell's ZigBee-on-a-chip for a couple of dollars per bulb.

LIFX (Kickstarter)
LIFX blew past its goal in October 2012, six months before Hue appeared on the market. The developer was looking to raise $100,000 and ended up with over 14 times that amount. To say there was a great deal of enthusiasm and support for the LIFX project is an understatement. The gadget freaks who frequent Kickstarter were looking for something very like what Hue delivered in March of this year, and LIFX has yet to deliver; it's at least four months overdue. (The Financial Times has a meditation, featuring LIFX, on the difficulties of getting manufacturing off the ground, and then scaled up. Only 50 percent of Kickstarter projects ship on schedule after successful funding.)

LIFX's control scheme is similar to Hue's but simpler, and more elegant, in one critical respect. Rather than relying on a separate, hard-wired bridge that speaks to ZigBee-equipped bulbs out the other end, in LIFX the bridge is contained in a master bulb. The control is wireless all the way, WiFi in and ZigBee out. Hue's architecture should give it an advantage in the range at which lights can be controlled with a smartphone: The WiFi signal from the home network's access point is likely to be stronger than one served from the base of a light bulb.

BlueBulb (FundAnything)
This project just met its goal for funding ($20,000) on one of the alternatives to Kickstarter, a site called FundAnything. Its control paradigm is far simpler than those of the projects above: Each bulb speaks Bluetooth, and each speaks it only to the iOS device with which it is paired, not with a bridge or with other bulbs.

This approach ought to have simplicity and cost advantages over going the WiFi and ZigBee route. And since this bulb is being designed and introduced later than Hue and LIFX, that timing ought to give it a cost advantage as well. Those advantages are not much in evidence: Backers of the funding campaign get one bulb for $58, or two for $54.50 each, or four for $52.25 each.

BlueBulb's control scheme is clearly more limited that those based on ZigBee, and it has no hope of scaling. You control one bulb at a time. I don't know what happens if you are within Bluetooth range of two or more bulbs with which the phone is paired.

ZigBee is more future-proof as well. It can be upgraded over the air, something not possible with Bluetooth. In the currently unsettled battle for supremacy among home automation standards, Loring Weibel wrote here that he is betting on IP protocols to win the day, ultimately.

Related links

— Keith Dawson , Editor-in-Chief, All LED Lighting