Wifi Lightbulbs | Postscapes

There are two types of Wi-Fi Lighting you might be looking for:

IP enabled lights that you can monitor, manage and control from any internet-enabled device. (Android@home, etc)
LED lights that are able to send data using Visible Light Communications (VLC) technology.

In this resource article we will cover both types of wireless light bulbs.

Visible Light Communications

Image: Bytelight

Visible frequencies generated by LED lights are being touted by researchers (See the history of the idea below) as a way to transmit data and supplement our exisiting information networks. Fluctuations of a bulb in a pattern that are imperceptible to the human eye, can be used to generate data transmission at average speeds of 10 megabits per second (and have been shown capable of reaching 100-500 Mbps).

wifi-lightbulb

Applications of the technology have the most potential where wireless transmissions cannot currently be used. Immediate benefits could be seen in hospitals, airplanes, hazardous environments, underwater operations, and in the military where the use of the light would enable activity that does not compromise safety and security standards.

The technology is also shown to be applicable for indoor GPS and in car-to-car communication from headlights and street lights to manage traffic flows and overt accidents.

A potential downside to this technology is its need to have line-of-site visiblity in order to work. This restriction can be reframed as a security benefit as the data cannot breach walls like typical Wi-Fi can.

Harald Haas, one of the professors working on this technology, gave a presentation at TEDGlobal in July 2011 talking about potential uses and demonstrating the technology sending video.

Thinking of outfitting your own home with these data lightbulbs? Advances will need to be made in Power Line Communications (PLC) technology in order to enable you to use existing home power lighting cables to carry the data. There will also need to be advances in the capacity to upload data through that same connection.

Regulations:
In most cases VLC is subject to regulation by a noncommunication standards (Ex: eye-safety standard, illumination regulation, automotive standards in the case of traffic signals). This presents challenges working across regulatory bodies and frameworks which most other communication standards do not have to do.

Line-of-site Limitations
Since this is a requirement it brings with it certain benefits (mainly security) and restraints like having interferance from atmospheric conditions like fog, rain, etc.

Speed Limitations:
The data transfer rate for LED transceivers is limited to 622 Mbit/s. Due to the characteristic switch hysteresis.

Companies in the industry:


LVX System	Nakagawa Laboratories	ByteLight

VLC Research

Northumbria University, Fraunhofer Heinrich Hertz Institute for Telecommunications, Siemens AG, Boston University, University of California.

History:

This concept of Visible Light Communications dates back to 1880 in connection to Alexander Graham Bell. Here is a brief history that begins with Bell's idea and follows through to the most recent discoveries and innovations.

	1880: The first VLC transmission (which was also the first wireless transmission in the world) was sent in Washington D.C. on 3 June 1880 by Dr. Alexander Graham Bell and his assistant Charles Sumner Tainter. They used a system they called the Photophone which transmitted speech on modulated sunlight over several hundred meters. This demonstration pre-dates the transmission of speech via radio and Bell is said to have stated it was his greatest achievement, surpassing even the telephone in terms of importance.
	1931: Dr. Sergius P. Grace, of the US Bell Telephone Laboratories, discusses the potential for using light for wireless communications to prevent the danger of eavesdropping by others.
Image Soure: Radio Museum	1955 The first visible light wireless remote control is made by Zenith and called the Flash-Matic Remote Control. This system used photoelectric cells in the four corners of the screen to control on/off,mute and channel selection. The Flash-matic had problems working well on sunny days, because sunlight often changed the channels at random. One year later, ultrasound technology was used to replace the light system to eliminate this flaw in the operation.
	2003: The Visible Light Communications Consortium (VLCC) is established between major Japanese companies to develop, plan, research and standardise Japan’s own visible light communication systems.
Image Source: Twibright	2006: RONJA The Reasonable Optical Near Joint Access (RONJA) Free Space Optics device developed in the Czech Republic can transmit data wirelessly using beams of red visible light up to 0.87 miles (1.4 kilometres), or infrared light up to 1.25 miles (0.78 kilometres).
	2009: A result of the joint cooperative agreement between VLCC and the IrDA, the VLCC issues their first Specification Standard.
	2009: IEEE 802.15 TG7 Task Group seven was chartered to write standards for free-space optical communication using visible light.
	2011: 100Mbit/s data rate was achieved from a standard low-cost LED light bulb by researchers on the D-Light project at the University of Edinburgh

Resources:

If you are interested in learning more about VLC technology and applications below is a list of videos and resources for your viewing pleasure.

Center for Ubiquitous Communication by Light (UC-Light) at the University of California
Visible Light Communications Consortium (VLCC)
IEEE 802.15 WPAN™Task Group 7 (TG7)Visible Light Communication
OMEGA project - Development of a global standard for ultra-broadband home networks (operating at 1 Gbit/s) LED-powered VLC is the key technology.
http://visiblelightcomm.com/ good blog on the topic.
The blog Twilight in the Valley of the Nerds does a good overview and the technology restraints in his article Is Li-Fi the Next Wi-Fi?

VLC Videos:

In the Media:

New Scientist: Will Li-Fi be the new Wi-Fi?
NYTimes: Using Light to Send Data Across the Room
The Engineer: Light reading: visible light communications
Good: Forget WiFi, Connect to the Internet Through Lightbulbs
MIT Sloan: Harald Haas’s Li-Fi Vision: Light Bulbs That Transmit Data
EE Times: Visible light illuminates a new approach for wireless comms

Wi-Fi IP bulbs:

With the rolling out of IpV6 all of the objects in your house will soon be able to have their own internet address. Wi-Fi enabled lightbulbs and home automation are one of the first industries to jump onto this technology enabling you to control your home lighting from any connected device, whether that's a laptop in your living room or your phone on the other side of the world.

Google and their Project Tungsten and Android@Home announcement in May sparked off a new flurry of excitement for the technology and its integration with our newly ubiquitous smartphones and tablets. Starting in 2012 you should be able to get your hands on these devices starting at prices ranging from $20 to about $35 for a 60-watt equivalent.

The technology behind this first round of wireless lightbulbs from NXP, Lighting Science Group and Google include:

- Based on 6LoWPAN (also supports the main lighting-relevant software stacks like Zigbee and JenNet)
- 2.4-GHz IEEE 802.15.4 standard-compatible wireless microcontroller.
- Needs a bridge/gateway to operate between the lights and your network

Additional Notes:

- Google demo used SNAP-enhanced 6LoWPAN from Synapse Wireless.
- Google plans to release their own home networking standard as part of its Android@Home initiative.
- JenNetIP—the framework that lets the bulbs talk to computers and devices has been open sourced by NXP. John Croteau, the general manager of power lighting solutions and high performance RF at NXP, reiterated this by saying: ‘There will not be an “internet of things” if technology is proprietary or with royalties. If it only works with the iPhone, it won’t be deployable.’

Additional Benefits:

- Should result in energy savings from more efficient usage like have lights automatically turn off when no one is in a room
- Automatically adjust lighting according to outdoor environment conditions.
- Can broadcast data to monitor usage over time.

Probable IP enabled bulbs: