Introduction and Component Analysis

The Internet of Things (IoT) revolution has sparked an increased interest in home automation. Lighting is one of the major home automation aspects. LIFX is one of the popular crowdfunded companies in this space to have come out with a successful product. The success of their multi-colored LED bulbs brought venture capital funding, allowing them to introduce a new product in their lineup - the White 800. The launch of the White 800 also coincided with firmware v2.00 for the LIFX bulbs.

The initial products from LIFX were multi-color LED bulbs similar to the Philips Hue. The new LIFX White 800 is a white LED bulb with tunable color temperature. Color temperature is an important aspect in the lighting environment. In addition to visual comfort, it also affects human behavioral aspects. Different color temperatures are desirable for different human activities. Therefore, tunable color temperature in a single light bulb is a good thing to have. The specifications of the White 800 indicate 890 lumens of brightness (60W-equivalent), 25000 hours lifetime (22.8 years @ 3 hrs/day), 11 W power consumption and tunable color temperature from 2700K to 6500K.

The first generation LIFX bulbs relied on Broadcom's WICED platform. It also had a TI chip for 802.15.4 mesh networking. However, the White 800 gets rid of the mesh networking aspect and uses the QCA 4002 low-power Wi-Fi platform. This enables a lower price point for the White 800 compared to the other bulbs in the LIFX lineup.

At the heart of the unit is the lighting control module (LCM). LIFX also seems to be targeting this board towards OEMs in addition to using it within the White 800.

LIFX Lighting Control Module (FCC filing)

THe LCM documentation gives more insight into the internal components of the board.

The unit uses a Freescale Kinetis micrcontroller (ARM Cortex-M4-based) coupled with the Qualcomm Atheros QCA 4002. The QCA 4002 is very similar to the AR9330 used in the Ubiquiti mFi devices. The integrated CPU is MIPS-based. It is tuned for low power operation and, correspondingly, lower host CPU performance. The AR933x can run full Linux, but the QCA 400x is targeted towards embedded platforms. In the LIFX, the configuration (QCA 4002) is a 1x1 802.11n 2.4 GHz connectivity platform with the RF switches integrated.

The use of the QCA 4002 software stack on the Kinetis microcontroller allows for AllSeen / AllJoyn certification (the IoT standard backed by Qualcomm). The LIFX White 800 also carries the 'works with nest' logo, thanks to the cloud back-end.

We have looked at the internal hardware in the LIFX White 800. In the next section, we look at what the average consumer sees - the setup and usage process.

Setup, Usage and APIs

The setup process for the LIFX White 800 is similar to most other IoT devices. The unit boots up with its own SSID. A mobile device (iOS or Android) with the LIFX app pre-installed is made to connect to it. A LIFX account is associated with the device. It enables control over Internet with communication via LIFX's servers.

Dimming is achieved via the core thumb-wheel in the app's home page. Color temperature can be tuned using the dial around it.

Many of the other app features such as themes are applicable to the multi-colored light bulbs. However, the scheduling feature works well with the White 800.

On the whole, the app is straightforward and easy to use.

We measured color temperature of the light bulb's out with a Samsung Galaxy S4 using a Light Meter app. The color temperature dial in the LIFX app was set to the two extreme temperature points for the screenshots below.

The color temperature measured as per the specifications and was obviously evident to the naked eye.

LIFX has been quite popular with power users. The communication protocol was reverse engineered, and there are multiple open source projects based on them. lifx-http, lifxjs and lifx-java are examples. Firmware v2.00 messed up many of these apps. However, it also brought along support for the official HTTP APIs. The APIs are a very good starting point and allow simple apps, but, unfortunately relies on the LIFX's web servers being up and the user's Internet connection being active (it is cloud-only). Recently, the official LAN-only documentation was updated. Hopefully, local HTTP APIs are made available soon - either officially from LIFX or via third-party developers.

Initially, LIFX didn't appear power-user friendly after the launch of v2.00 of the firmware, but things are slowly getting better with the publishing of the LAN protocol. The main item in our wishlist with respect to usage / APIs is a web interface for the bulb - the ability to control the light temperature and brightness using a web browser. This interface could also double up as an official 'mobile app' for platforms such as Windows Mobile.

Miscellaneous Aspects and Concluding Remarks

Prior to proceeding to the business end of the review, we look at a couple of different aspects that affect the end-user experience - power consumption and thermals. We recorded power consumption and power factor values using the Ubiquiti Networks mPower Pro power strip at various brightness levels. The good news is that the White 800 consumes very little power (~ 700 mW) in the standby mode after recent firmware updates. It was close to 2W at launch, but it is too low to measure reliably on the AC side now. (Update: We shifted the power measurement duties to the Visible Energy UFO Power Center. It can measure sub-1 W numbers more reliably compared to the Ubiquiti Networks mPower devices. The table below has been updated for the standby setting.)

LIFX White 800 Power Consumption Brightness Level Avg. Power (W) Power Factor 0% [ Off / Accessible via App ] 0.69 W 25% 1.32 W 0.50 50% 3.08 W 0.49 75% 5.88 W 0.67 100% 10.71 W 0.89

There was no measurable variation in the power numbers when the color temperature was tuned (for a particular brightness level).

In order to evaluate the thermal performance, we kept the light on at the maximum brightness level for a hour and recorded a thermal image (using the Seek Thermal smartphone add-on). As recommended for any 'high-power' LED fixture, it would be good to not install the unit in a tight space with inadequate airflow. (Update: It has been brought to my notice that the LIFX bulbs have been "UL box" tested (that's a standard ~6" wooden cube, open on one end - simulating an air starved ceiling fitting), and should meet their stated lifetimes in an open air fitting. Everything in the bulb is rated for 105 C operation)

The following table summarizes the various home automation aspects / consumer checklist for the LIFX White 800 and how it compares with the other systems that we have evaluated before.

Home Automation Device Aspects - Summary Table Aspect LIFX White 800 Ubiquiti Networks mFi Belkin WeMo Ubiquiti Networks mFi Belkin WeMo LIFX White 800 Evaluated Devices LIFX White 800 mPower

mPower Pro

InWall Outlet

InWall Dimmer Switch Communication Technology Wi-Fi (2.4 GHz) Wi-Fi (2.4 GHz) Platform Qualcomm Atheros QCA 4002 1x1 802.11n Wi-Fi SoC

Freescale Kinetis MK22FN512 MCU Qualcomm Atheros AR9331 1x1 802.11n Wi-Fi SoC

Host CPU: MIPS 24Kc, DRAM: 32MB Power Source AC Powered AC Powered Hub / Bridge Requirement No No Control Center Local Device (basic access, rules and scenes)

Cloud (for control over the Internet) Local Device (basic access, rules and scenes)

Local Server (comprehensive access, rules and scenes) User Control Interface Mobile Apps Web Browser

Mobile Apps (basic control) Open APIs Yes (Protocol Documentation)

HTTP (Cloud-only) Yes (uPnP, HTTP, SSH) Third-party / Hub Compatibility AllSeen / works with nest /IFTTT None advertised Cloud Reliance Optional (only for access from an external network) None Security Notes Username / Password authentication at app level Username / Password Authentication

LAN Access Only User Support / Discussion Forums LIFX Support Ubiquiti Networks Community - mFi Forums Street Price USD 40 USD 60 (mPower)

USD 95 (mPower Pro)

USD 59 (InWall Outlet)

USD 59 (InWall Switch / Dimmer)

With respect to the open APIs, we would like the LIFX bulbs to present a simpler interface for power users. HTTP APIs and a web server (that could also act as an interface on PCs) similar to that of the UFO Power Center or the Ubiquiti Networks mFi devices would be great. In terms of hardware, we observed audible buzzing with any brightness setting under 100%. This might not be a problem for ceiling fixtures, but is definitely a factor when the bulb is within earshot for those sensitive to such noise. Unfortunately, this is a problem with most dimmable LED fixtures.

Other than the above two aspects, the LIFX White 800 is a reasonably-priced smart lighting fixture. The tunable color temperature differentiates it from the host of multi-colored smart LED bulbs in the market. The low-power Qualcomm Atheros QCA4002 platform is also instrumental in driving down the power consumption and price for widespread adoption.