Original Link: http://www.anandtech.com/show/6805/philips-hue-automated-home-lighting-gets-colorful



Introducing the Philips Hue

Before we get started, we’d like to introduce Ashu Joshi to our readers. He has a background in networking and has used a variety of home automation devices over the years. As such, he brings a useful perspective to our staff and can help augment our review coverage. Note also that as with all of our articles, these pieces reflect the opinions of the writer(s) and are not in any way associated with or influenced by any other source (e.g. other employers).

Philips sent out a review sample of their new Hue lighting system, a set of three Hue lights with the Hue Bridge that allows you to remotely control the lights. Besides being able to turn the lights on or off, the big claim to fame of the Hue is that you can set the lights to a variety of colors, or you can even program them to cycle through colors. Home automation systems are often proprietary and can be quite expensive, so the entry of Philips into this market (albeit in a limited fashion) with their Hue lighting system has the potential to shake things up a bit.

The lights have colored LEDs, and while the initial pack only includes three Connected Bulbs (referred to informally as "bulb" or "light" throughout the remainder of this review), you can potentially add up to 50 lights throughout your house/property. One thing that hasn’t changed yet however is that pricing is quite high: the initial Starter Pack will set you back $200. But how does the Philips Hue work in practice, and could it be worth the cost of entry? Note that at present, the Philips Hue is only appears to be sold through the Apple Store as an “App-Enabled Accessory”, but Android is also supported. Long-term we will likely see support for other operating systems as well, but for now this is primarily an iOS/Android targeted device.

Packaging and Contents

One thing that immediately stands out with the Philips Hue is the packaging. It’s very well designed and eye-catching, and I love that you’re able to get a preview of the lighting options with the dial on the box. I set up my Philips Hue controller and bulbs recently, and my initial impressions have been very positive. It’s very easy to install and the experience of this lighting system is quite the change from your everyday lights. I uploaded a few videos of the package in action so you can see what it looks like.

Included in the package are three Connected Bulbs, and they’re quite a bit heavier than a typical light bulb. Most likely the added weight comes from the controller and antenna necessary to talk to the network, and possibly the addition of multi-colored LEDs adds a bit as well. Whatever the reason for the added weight, at least the heft makes you feel like you’re getting a bit extra for the $60 per light.

The other major item included with the Starter Pack is the Hue Bridge. This is a small, circular, lightweight controller with three LEDs on the top and a large circular button in the center used for the pairing function—Philips refers to it as the “link” button. On the side is an Ethernet port to connect to the home network and a power receptacle. The three LEDs show the status of Power, Ethernet, and Internet connections. There is no lettering to indicate what the LEDs are for but they use fairly common icons to indicate the function.

You also get a power adapter with a reasonably long cable for the Hue Bridge, though this is somewhat subjective. I have seen plenty of products where to save pennies they have short cables that ruin the setup experience and force the use of an extension cord, but for most users the Hue adapter should prove sufficiently long. An Ethernet cable is also provided to connect the Hue Bridge to your network, so plan ahead and realize that the Hue Bridge will need both power and network wires and place it accordingly.



Philips Hue Setup

The setup process is very easy and at no point do you need a PC or a Mac computer—everything can be done using a Smartphone or a Tablet. The first step for any automation controller that can be controlled over the Home Network or Internet is to get it on the Network, naturally. Philips makes this easy by sticking with Ethernet for the Hue Bridge.

As far as the setup procedure, the first step is to screw in the Connected Bulbs and turn them on. All the bulbs turn on just like normal light bulbs, with a default white light. Once all the bulbs are screwed in and powered on, plug the Hue Bridge into an Ethernet port connected to your home router/gateway and apply power.

The Hue Bridge boots in less than 20 seconds (you can see the boot process in this short video). The next step is to install the app from the Apple App Store on your iOS device (or the Google Play Store for Android).At this point, make sure that your smartphone WiFi is on and connected to your home network. Fire up the app and it will instruct you to press the “link” button on the controller. When you press the button the app discovers the Hue Bridge and you should be ready to go. In my case, it automatically discovered all the three bulbs and they showed up in the app.

From the App settings section it’s possible to rename each bulb to give it a meaningful location. To help with this process, when you select one of the bulbs in the app the corresponding physical bulb starts blinking to show you which light you’re adjusting. This is a handy feature for the initial setup, and it could be even more important if you happen to have a lot of Connected Bulbs.

The app comes with multiple scenes that set the lighting ambience to predefined levels. You can also snap a photo and let the app decide on the appropriate color(s), and you can save all of these settings to new “scenes” (e.g. you might have one setting for a regular dinner with a different settings for a “romantic dinner”). There is also an option in the app to add more Bridges or bulbs, but I have not been able to try that yet. It seems pretty straightforward: adding a new bulb takes you to a page on the Smartphone that instructs you to screw in the new light, turn power on, and start the search.

It’s also possible to control Hue from more than one device (e.g. a tablet, a phone, and maybe the phone of a significant other). The process is as before: download the app, make sure you are on the home network (WiFi), fire it up, and when the app prompts press the “link” button on the Hue Controller and it is paired to the network. (This works very similar to the Sonos app as well.) If you have edited the names of the bulbs (for example I called one of them “FormalDiningLamp”), the other devices will pick up the names as they’re all stored in the Hue Bridge (so thankfully you only have to input the names once).

Controlling the Bridge locally is pretty simple, but if you want to be able to manage the lighting when you’re not at home (e.g. you’re not connected to your home network), you’ll need to create an account on MeetHue.com. Select the “Login to portal” option within the app and it will open up a browser with the account creation page. The page is clearly designed for phones and tablets and after a few guided steps you should be all set. Once you confirm whether you’re using a smartphone or a tablet you can then control the lights from anywhere with Internet access (provided of course that your home network stays up).



Teardown and Design

The Hue Bridge has two screws that you need to remove before you can pop off the back. Even with the screws out, popping the back off is tricky—it has an interesting snap-in mechanism. Here’s what the back looks look like; the two white “feet” at the bottom are covering the screws. I used tools from iFixIt to get this open.

Once you open it up, you can see the back side of the PCB, and the snap-in connecter I mentioned earlier.

The PCB is connected to the front of the Bridge using a ribbon connector. This cable provides the power and signals for the LEDs and the Link button.

The main PCB has the two primary components of the Hue Bridge, an ST Microelectronics STM32F217VE Microcontrollerand a Texas Instruments CC2530 ZigBee Controller.

There is also an RF range extender (CC2590) coupled to the CC2530. The STM MCU has an integrated Ethernet controller, but as a whole the design has very few components. It’s clear that the majority of the cost for the Starter Pack is in the bulbs and not in the Bridge. (Based on the total kit price, the Bridge is $20 more than the cost of the three bulbs, though of course that leaves plenty of room for profit margins.) The image below shows the antenna for ZigBee:

I’ll cover the technology behind the Hue Bridge in a moment, but the choice of microcontroller for this design is a clear indication that this is primarily a purpose-built device. That is, it does not have the horsepower to extend to different types of applications due to the limitations of the CPU and the amount of memory. Nonetheless, it is well suited for the function at hand; let’s look at the specifics of the technology behind Hue before we get into a discussion of what it can and cannot do.



Technology

Philips Hue uses ZigBee (more specifically ZigBee Light Link) to control the Connected Bulbs. Of course, smartphones and tablets don’t have ZigBee built into them, nor for that matter do PCs and Macs (yes, you could get a ZigBee USB dongle if you wanted), and hence the need for the Hue Bridge. It basically acts as a link between the devices running Apps that use the home network/WiFi and the ZigBee link to the bulbs. The App sends the command to the Bridge, the Bridge converts it to the ZigBee protocol, and vice versa. ZigBee operates in the 900-928MHz band in North America and Australia, 868MHz in Europe, and 900-924MHz plus 2.4GHz worldwide.

You might think that the bridge is simply an additional device; why not make the bulbs WiFi? It’s a valid question and it could be done, but imagine trying to get each bulb connected to the network. Technically savvy users could likely figure it out, but for everyone else it would be a nightmare. I’ve tried helping friends and family with basic WiFi configuration issues over the phone, using PCs where all they need to do is enter the network password, and it can still be a pain. Trying to deal with IP addresses and potential conflicts on a per-bulb basis isn’t something most people would be interested in doing.

There are additional factors as well, such as cost, power consumption of WiFi vs. ZigBee, and range requirements. ZigBee range is typically lower than 2.4GHz WiFi range; however, ZigBee is a mesh network so each device added can function as a repeater to extend the coverage area. That means as long as there are some devices closer to the Bridge coverage should be sufficient. ZigBee also consumes less power than WiFi and usually costs less as well, which is important when you’re looking at integrating the functionality into devices like bulbs.

Ultimately, though, I think managing the setup and being able to control the bulbs effectively are the primary reasons why ZigBee is the right choice. Having the Bridge also makes it far easier to use multiple devices to communicate with the network, and it makes the creation and use of an app a lot simpler as well.



The Philips Hue Experience

Subjectively, I find the light from the Hue system looks beautiful; it’s also fun watching the different combinations (or scenes) pre-programmed into the app. If not for the $60 per Connected Bulb price, I would seriously consider getting more lights and having them all over my home. ­­I’m not going to try and reproduce pictures and videos showing what Hue looks like in action, as you can experience that on MeetHue.com, but it definitely creates a different feel than having standard lights.

There are many pre-programmed scenes that come with the app (and others are available online, including user-created scenes). If you can’t find something you like, however, you can easily edit existing scenes or create new ones. The app gives you the ability to set both the brightness and the color of each bulb and then save that setting, and you can group these settings so that, for example, your living room light settings are separate from your bedroom light settings.

There is no observable latency when controlling the lights while on the home network. The bulbs respond to changes with barely perceptible lag when being controlled from the smartphone. They ramp up/down to the specified brightness level and you can see the gradual change of color or brightness. This makes sense as an abrupt change would make for a very harsh experience.

Once you leave the home network and control the lights over the Internet, the lag/latency increases to around 8-12 seconds. I was able to simulate this by turning off my phone’s WiFi connection and using its data connection, but however you do it the results should be similar. When you’re remotely managing the lighting, there are a few extra steps that account for the delay, as communication has to go through a server that then has to send commands over the Internet to your Hue Bridge. Now you have to use the app to connect to the MeetHue portal (which takes around 8-10 seconds initially). Once connected the bulbs respond to changes to a new scene or to turn on/off in around 5-8 seconds. Depending on the protocol used and the server load, this could account for the majority of the lag, but it’s worth noting that instant responses to remote changes in lighting levels don’t really matter since you’re not physically there to see what’s happening anyway.



Testing

Besides the setup process and features, there are a couple of questions that may be important. First is the total number of devices that can be supported, and second is the range of coverage that's provided. Testing either of these can be a bit tricky, but I did make an effort to find the range limit of the Bridge.

To test the range of the Bridge on its own, I placed the Bridge in a corner of my basement and powered off the two other lights (they were unscrewed so physically they’re no longer present on the network). Then I moved the remaining light to the farthest corner of my house, a second story bedroom. The total distance between the Bridge and the light is approximately [50] feet, and there are two floors and four or five walls between the Bridge and the bulb. Even at that range and with all the material potentially interfering with communication, the Bridge was still able to see the bulb, so if that sort of range propagation holds for communication between the lights, coverage should be fine in most layouts. If you had a gigantic estate with lights spaced out hundreds of feet between them, you might run into problems, but that's a corner case at best; typical homes should be fine.

The second question—the number of total devices supported—is something that we couldn't actually test, as we only had the three bulbs in the Starter Pack and with a cost of around $60 per additional bulb I wasn't about to try to overload the network. (Yeah, sorry—I didn't have a spare $3000 lying around waiting to be invested in Hue lights!) Philips states that the Hue Bridge can support up to 50 bulbs, which should be sufficient for a moderate size house.

What isn't clear is whether or not you can increase the total number of devices by adding additional Bridges to the location. Given the use of the ZigBee controller along with the fact that there is no configuration on a per device level to connect it to the network (e.g. you just buy additional bulbs and they apparently broadcast and communicate with any and all Hue devices), we would assume that 50 lights and a single Bridge is about as far as you'll be able to go within a single area. Conceivably, there could also be problems if your immediate neighbor also picked up a Hue—how would the lights know to talk to your Hue network and not his? This is both the blessing and curse of going with an easy to configure technology.

In the process of testing the range I made some other interesting observations on the behavior of the Hue lighting system. First, I powered off the Hue Bridge (to move it to the basement), and while it was powered off I launched the app. The app did not complain about not being able to connect to the Bridge. Then I touched “All Off” in the app, and again the app shows no error; the app is behaving as if the Hue Bridge is up and alive. However if you go into settings the Bridge has disappeared, and the entry says “Find new bridge”.

In theory it’s of course possible for the Internet to have issues that prevent communication with the Bridge, or for your home network to have problems. Rather than behaving as though nothing is wrong (until you go into the settings and find your Bridge is no longer present), it would make more sense to update the app to let users know that there is a problem communicating with the Bridge. This should be a relatively simple update on the app side.

Similar behavior is exhibited when you disconnect the bulbs from power. The bulbs don’t disappear from the app, and if you send a command to a non-present bulb the app behaves as though nothing is wrong. This may not be a huge problem, but potentially someone could turn off a light switch and thus cause a bulb to power off. While showing a communication error message that needs to be dismissed every time that happens (especially if there are many bulbs on the network) could become quite annoying, a small note at the bottom of the app or a greyed out bulb icon in the app indicating that communication with the bulb failed and to check the power would be easy to implement. Once more this is something that could be fixed with an app update and/or a Hue Bridge software update in the future.

Power Consumption

I used Kill-A-Watt to do some basic power measurements in the “Off” vs. in the “On” state as set by the app for a bulb. When the bulb is on and set to maximum brightness, it consumes about 0.08-0.09 Amps (about 5.4 Watts). In the off state (but still drawing some power so that it can communicate with the network), each bulb draws around 0.01 to 0.02 Amps (about 0.4 Watts). As expected, even when the LEDs are off power draw is not zero. The ZigBee network controller and other circuitry need to remain active in order to listen for communications from the Bridge.

While it might be possible to cut power use in the “off” state further by having the bulbs go into a low-power sleep state and only wake up for a short period of time every second or two, that would only work in a non-mesh network (or perhaps if the bulbs could all stay in perfect sync so that they’re awake at the same time). Given the complications associated with such an approach, keeping the design simple appears to be the best solution, and that’s what Philips has done.

In a worst-case scenario, if you have a fully populated network of 50 Connected Bulbs, each will draw approximately 1W more than a regular light in order to run the communication hardware. Over the course of a year, that will add up to 236kWh of power, or approximately $24 (at around $0.10 per kWh), which is negligible in comparison to the $3000+ in lights that you’ll have spent. For the Starter Pack and three bulbs, you’re looking at around $1 per year, not to mention compared to incandescent lights you’re already cutting power use per light by about 55W, so it should come out as a large net savings (though not compared to running non-connected LED lights everywhere). The minimal power use while “off” should not be a big issue for most people, but the cost of being able to remotely control does come with a small cost (beyond the initial expenditure for the hardware).



Hue as a Home Automation Controller

Given the fact that Hue uses a ZigBee controller, one of the questions some will have is whether the Hue can be extended to support other devices. While it’s possible for Philips to create other devices that could work with Hue, I have serious doubts that the Bridge can act as a sophisticated home automation device given the choice of the microcontroller and the amount of memory on the Bridge controller. If Philips changes the firmware on the ZigBee controller in the Bridge, it could be extended to control other ZigBee devices in the home, but right now it appears that the CC2530 is being used in the Light Link profile of ZigBee.

Despite my doubts, the hacker community amazes me. A simple Google search brought me to this site, run by Ross McKillop. Ross has reverse engineered the HTTP protocol between the App and the Hue Bridge, and it appears that communication is done in the open, not with SSL. (Potentially the CPU on the Bridge just isn’t fast enough to make SSL encryption viable.) He has additional details, but then goes on to link to EveryHue as a source of further unofficial help/discussion.

Philips has stated their intention to open up the APIs and the app SDKs for developers. Once they do this I have no doubt that there is an immense potential to use the Hue in interesting ways that perhaps weren’t part of Philips’ initial plan. I can imagine Universal Remote controllers that are app-based tying into the Hue or high end systems such as those from Control4, or perhaps a GoogleTV app that controls the bulbs in your living room while watching a movie. Only time will tell what the hacking community will do with Hue as they gain more experience.

Closing Thoughts

The Philips Hue is at present a unique and interesting lighting system with elements of home automation that can be attractive to a diverse set of users. I found it was easy to set it up and I’ve really enjoyed the experience of having the lighting scenes and controls if affords. However, like any other consumer electronics device, the Hue has its pros and cons.

The good aspects include the aforementioned ease of setup; many home automation devices can get pretty complex, especially for the less technically inclined. Hue is relatively simple in terms of what it allows, and that helps to keep the learning curve pretty shallow. Once it’s up and running, it can provide some really cool functions, and it’s sure to be a great conversation topic at your next party. Finally, while we couldn’t fully test this, the Hue Bridge appears to have very good range so communicating with lights within any reasonably sized house shouldn’t be a problem—if your WiFi can cover the area, Hue should be able to do that and more (via its mesh network).

Not all is perfect, however. At present, there’s very limited extensibility or integration today. Hue does one thing and does it reasonably well, but if you want to use it as part of an existing platform you’ll have to do quite a bit more work. This is yet another app/system for home automation, and if you’re already invested into one of the other solutions you might want to wait for the APIs to open up and let someone else get Hue working with whatever platform you’re running. The other major hurdle to overcome is the price, which is often the case with home automation. At $200 for the Starter Pack with just three Connected Bulbs and the Hue Bridge, you basically only get enough lights to handle a single moderately sized room, or perhaps three smaller rooms. Additional Connected Bulbs will run $60 each (plus shipping and tax), and while the colored lighting offered by Hue is unusual, that’s still three to ten times as much as you’ll pay for other LED bulbs.

For those with the money and interest in colored lights, though, I think the Hue lighting system can be a great way to go. It provides a good base set of features and functionality right now, and over time I expect things will continue to improve as others get creative with the hardware and software. I would personally highly recommend the Philips Hue, but it’s definitely not the type of product that will appeal to everyone.

Log in

Don't have an account? Sign up now