Bluetooth mesh networking technology is finally here. Was it worth waiting for? Can it really drive widespread adoption of connected solid-state lighting (SSL)? And what exactly does it mean that it has been designed for professional lighting applications? As one of the leading contributors to the development of this new wireless standard, Silvair has answers to questions you might be asking yourself today. Let's review the development of the standard and consider the impact it may have in bringing LED lighting into the Internet of Things (IoT) movement.
A PINCH OF HISTORY
For Silvair, the interest in Bluetooth all started back in 2013 when Google rolled out Android 4.3 with API level 18, introducing support for Bluetooth Low Energy (BLE). At that time, the company wasn't too familiar with Bluetooth, but already knew that IPv6 over the 802.15.4 standard (used by ZigBee, for example) was a pipe dream. Even with the 6Lo compression (6LoWPAN - Ipv6 over Low Power Wireless Personal Area Network, a lightweight protocol envisioned to bring IP networking to embedded or IoT devices), IPv6 was simply too heavy to fly, and 802.15.4 turned out to be too slow to give it a lift. Back in 2012-2013, Silvair was experimenting with something very similar to what Thread is today. But eventually we found this combination (IPv6 + 802.15.4) incapable of addressing the needs of professional wireless lighting. Hence, Silvair kept looking for a suitable radio technology.
Google's announcement of support for Bluetooth Low Energy in Android sparked hopes. BLE was already supported by iOS, so with Android on board, it seemed like a good candidate to try. But it did not fly, either. The single-hop range was very limited and the hub-and-spoke topology was far from anything usable for lighting needs; it could provide only a handful of point-to-point connections. Great for linking a heart rate monitor to a phone but certainly not to control a ceiling with 500 lights in a hotel lobby. There was hope, though.
BLE OFFERED THE PHYSICS
The underlying physics of BLE was very promising. Within a couple of months, Silvair managed to build a BLE module capable of communicating over a 500m single-hop distance. The company also discovered that with proper software engineering, it was able to run multiple Bluetooth roles (a GAP Observer and a GAP Broadcaster) at the same time (GAP stands for General Access Profile). This experiment was carried out in early 2014 and you can see it now being the fundamental requirement of the Mesh Profile specification (see the last paragraph in Section 3.3.1).
This could be described as the conception of Bluetooth mesh networking. After all, if the software part of an off-the-shelf Bluetooth SoC (system-on-chip) could be modified in a way that allowed receiving and retransmitting messages, building a mesh network on Bluetooth would be possible. It was "just" a matter of nailing down the details of this software and documenting it as an open specification, so others could do the same.
This "just" step took more than three years and resulted in the publication of three specifications, approximately 1000 pages combined. Indeed, it is a complex solution. But along the way, it turned out that a solid technology for connected lighting simply could not be outlined in a dozen pages and delivered within several months. The nature of wireless mesh networks is complex. Jet engines are complex, too. Cars are complex. So are cellular networks and many other technology wonders we're using every day. They are all successful because they are complex and solve the intricate nature of problems. This is what Bluetooth mesh is doing, too - trying to address the complex challenge of low-power communications in the resource-scarce IoT environment while ensuring wire-like performance in connected lighting networks. Many technologies have promised that, but none of them has delivered so far.
IT'S ALL ABOUT THE PACKET
Why should we trust that Bluetooth mesh will be different? As the Bluetooth mesh networking specifications are now public, we can start dissecting and discussing various building blocks of this new wireless standard. There are many novel and unique concepts in mesh, but perhaps the key asset and differentiator is the packet. It is extremely compact. This compactness contributes to the spectral efficiency (and throughput) of Bluetooth mesh networks.
Radio is a shared medium and data-packet collisions are one of the key problems to address. This is what makes scalability such an enormous challenge in connected lighting networks. The math is simple: A shorter packet means fewer collisions. But how short can it be? The answer is up to 29 bytes, as described in Section 3.4.4 of the Mesh Profile specification.
Of course, such design begins with the basics: compressed binary payload instead of a text representation. Covering a broad set of use cases (including connected lighting, building automation, and sensors), 11 bytes for the application payload seems appropriate. The standard allows 1-2 bytes for an opcode and up to 10 bytes for parameters, such as a value measured by a sensor, or a multidimensional light (light level, hue, saturation) with a transition time.
On top of that, there are two items that may be considered overhead, but it is an absolutely necessary overhead: addressing and propagation control (SRC, DST, CTL+TTL: 5 bytes in total) and security (IVI+NID, SEQ, AppMIC, and NetMIC). The IVI+NID is 1 byte. This byte helps identify a network (is this a network I know and have keys to interact with?). SEQ is 3 bytes and together with the unique concept of a slowly propagated IV Index, forms a 7-byte-long sequence number. Each packet sent on a mesh network has a unique sequence number, per given SRC address. The smart part here is that only 3 bytes are included in the air interface packet. The remaining 4 bytes are slow changing and are "known" to the network. Sequence is essential in two areas: detecting replayed packets (very trivial security attack) and also being the key ingredient of both network and application nonces - see Section 3.8.5 of the aforementioned spec.
SECURING THE SYSTEM
MICs, or Message Integrity Checks, define the level of security of the system. Bluetooth mesh has dual-layer security - it includes the network layer and the application layer. Messages may be secured with two independent keys. This is useful for relay nodes to authenticate a message on a network layer without enabling tampering with the application payload. A lightbulb that relays a message to a door lock cannot change the payload from "open" to "close," but it does check whether the packet belongs to its own network. The network layer MIC can be either 8 or 4 bytes long. In its shorter form, it is combined with the application layer MIC that can again be 8 or 4 bytes long.
The end result is an application payload that is sufficient for almost any building automation, lighting control, and sensor application, with strong security and flexible addressing. And this all comes in an extremely compact form factor. Combined with the modulation scheme offered by BLE, it is also feather light. Including all necessary radio interface fields, such as a preamble, an access address, and a CRC (cyclical redundancy check), it totals 47 octets. As a result, a single transmission on a single frequency lasts less than 400 μs. This is 10× less than it takes to transmit a comparable message using other existing wireless technologies. And when using the new 2M PHY introduced by Bluetooth 5, this advantage can potentially be doubled.
The success of any wireless system fundamentally relies on the spectral efficiency. It is similar to how the success of an airliner fundamentally rests on its fuel efficiency. In the low-power, ultrashort-message category, Bluetooth mesh delivers an order of magnitude more than other wireless solutions. As far as data transmission is concerned, it is the first wireless standard capable of meeting the enormous expectations of the IoT era.
Still, you may wonder why a technology from the IT and telecommunications field is right for lighting. When working on the architecture of the Bluetooth mesh system, the Bluetooth SIG's (Special Interest Group's) Mesh Working Group kept on diving deep into the roots of problems it was aiming to solve. In particular, the team of contributors has focused strongly on addressing the many challenges of the smart lighting environment. There are many reasons to treat lighting as the primary application for a mesh system. Most important, lights are everywhere and they are powered. So depending on how you look at it, a lighting control system may be the goal itself or may just be the initial step to develop more services that are based on a mesh-connected infrastructure.
Imagine an airport, a hospital, a company campus, or a high-rise, multi-tenant office building. Now imagine you want to roll out a service that requires a dense infrastructure of radio nodes - perhaps thousands of them. Rolling out adequate hardware would be very expensive, as each component would require a mounting point and power supply. Now suppose that each light is already mounted and powered, and is capable of supporting your wireless application. Suddenly, you realize the hardware is already there: a mesh network of thousands of low-power wireless computing nodes.
This is why the lighting category is so crucial for Bluetooth mesh technology. And to be a winning solution in that category, the new wireless standard had to be outstanding for connected lighting applications. Everything else comes afterward.
A TOUGH WORLD OF LIGHTING CONTROLS
There are many important details that contribute to why a given solution is good for lighting. Let's take a closer look at two simple examples.
First, consider eliminating the so-called popcorn effect. There are two challenges for wireless lighting control systems here:
A lot of effort has been put into ensuring that Bluetooth mesh networking can effectively address both of these challenges. First, it is primarily optimized for multicast traffic. So regardless of whether there are ten, a hundred, or a thousand lights in a ceiling, they can all be addressed with a single message that goes out. This message, in real life, may reach around 90% of lights. To ensure that all of them are eventually reached, the message is repeated a couple of times. With two messages, the probability of delivery of at least one message goes up to approximately 99%. With five messages in a row, the reliability jumps to five nines, or 99.999%.
Now, some lights will receive the first message, while some lights will receive one of the later messages. But we want all of the lights to turn on at exactly the same time, since this is how lighting controls have worked for us for decades. How does the new standard ensure that? Here comes the Delay parameter to the rescue. Let's say that five messages are spaced 20 ms apart. The first one goes out at T=0 with the Delay set to 100 ms. The second is sent at T=20 ms with the Delay set to 80 ms. The scheme repeats until the fifth message is sent at T=100 ms with the Delay set to 0. Now, regardless of which one is picked by a given light, all lights will turn on at exactly the same time. Of course, there is the overall execution delay of 100 ms, but that is below the human perception level. The speed of the underlying radio, combined with multicast transmissions and time-compensated retransmissions, guarantees that the final effect matches application requirements.
The second example is simpler but nicely illustrates the attention to details characterizing the Bluetooth mesh specifications. How does a lighting system behave when the power is cut off and restored later on? How should it behave? The answer is that it depends. Of course, it depends on the type of lights, what purpose they serve, etc. In some cases, you might not want a power cycle to turn the lights on (this is unfortunately the case with some popular home lighting systems). But in many other scenarios, this may be the desired behavior.
In Bluetooth mesh networking, there is a configuration state called OnPowerUp (Section 3.1.4 of the Mesh Model specification). It can be set to Off, Default, or Restore (to the last value before the power was cut off). It works in tandem with another configuration state, the Light Lightness Default (Section 22.214.171.124), which can be any arbitrary level, or the last non-zero value (e.g., if you dimmed the lights down to 20% and then turned them off, after a power cycle they will turn on but at 20%, not at their full brightness). Again, the attention to tiny details presented by the design team seems to be going much deeper than in the case of other wireless solutions.
SCALING IT UP
Scalability was the initial reason why Silvair turned to BLE when trying to find a foundation for a robust low-power mesh networking technology. Its wireless capabilities were simply much better than anything else available. This was primarily due to the extremely compact packet structure, which flies over the fastest low-energy radio. But, of course, every solution has certain limits. So what are the limits of Bluetooth mesh? The answer is, as always, it depends. It depends what the network is doing (how many and what types of messages it keeps sending around) and how it is set up. Bluetooth mesh has many parameters that may be fine-tuned to adjust its performance to specific requirements.
As a general rule of thumb, one can assume that at 200 devices (or fewer), there is no need to worry about any tuning at all. The likelihood that any two communications will collide is pretty low. So let them loose at will.
Above 200 devices, depending on how talkative they are, some collisions might occur. This is why Bluetooth mesh provides a number of tools that help optimize the network and let it grow significantly while maintaining an excellent packet delivery ratio. The most important ones include the following.
TTL, or Time To Live. It defines how many relay hops a message is allowed to travel. It is rarely the case for large networks that every sender has to be heard across the entire network. An occupancy sensor, for example, usually needs to report only to light fixtures in the same room. And maybe to a gateway, but not across the entire building, to locations where nobody is interested in its status. Setting the Default TTL to a low value (even to 0 in some cases) is a good way to significantly increase scalability.
Relays. They retransmit received messages, obviously multiplying traffic in a given space. Usually, the default setting for the relay function is "on" in order to make setting up small networks seamless. In large networks, it pays to carefully select how many devices are designated as relays and disable relaying where it is not needed. Ericsson Research has recently published a thorough case study (http://bit.ly/2xV2XLm) modeling an office floor with close to 900 talkative mesh devices. It is based on real data captured from a live network. It shows that for a case like an office floor, it is enough to assign about 1.5% of nodes as relays.
Subnets. Mesh networks can be significant in size, spanning entire multi-story buildings. But it is extremely rare that devices on separate floors need to communicate with each other. Except for administrative tasks like re-keying the entire network or shutting down the whole building, typically each floor is self-contained. This fact is why subnets are a great mechanism to confine network traffic. A mesh node can be a member of multiple subnets, so it is a good practice to have the base network spanning all floors and then have a subnet defined for each floor. And to configure the nodes to transmit only on subnets they belong to, not on the main network (except the administrative tasks). A single mesh network can have more than 4000 subnets. We have yet to build a structure that vast. Until then, subnets should help in scaling up any network you imagine.
IS THIS THE BEGINNING OF A NEW ERA?
According to wireless architects from Silvair, the v1.0 of Bluetooth mesh is much more capable than anybody has anticipated. It is a complete system for low-power, fully-interoperable mesh networking, with a deep and flexible application layer addressed in the Mesh Model and Mesh Device Properties specifications. By defining basic functionalities of network nodes, mesh models make devices aware of what function they perform, what other nodes they can connect with, and what actions can be performed upon them.
To enable maximum design flexibility, models include multiple properties that can be adjusted in accordance with specific applications. In addition to covering a full range of standard lighting functionalities, mesh models fully support additional functionality such as advanced lighting control strategies including occupancy sensing, daylight harvesting, or time scheduling. They also come with multiple tunable parameters and properties, effectively future-proofing buildings against increasingly stringent environmental requirements that we can expect to see as the world strives for a low carbon future.
With the Bluetooth mesh networking specifications already published, we will soon be able to see how these networks perform in practice, and whether this new wireless standard has what it takes to move connected lighting to another level. What already seems certain is that no other technology has fostered such a comprehensive approach to challenges typical for lighting applications. Time will tell whether this is enough.
Source: LEDs Magazine
Networked lighting controls are intelligent and programmable systems in which devices communicate to enact control strategies. Despite the extraordinary potential of these systems, adoption has been inhibited by difficulty in reliably projecting energy savings, unfamiliarity among specifiers and, notably, contractors, interoperability and complexity issues and cost. If some of these issues are addressed, the U.S. Department of Energy forecasts penetration of 28 percent in 2020 and 52 percent in 2025 in the commercial building installed lighting base.
Based on utility interest in increasing energy savings by using networked lighting controls, the DesignLights Consortium (DLC) launched an ambitious market transformation program focusing on a specification for networked lighting controls that utility rebates programs can use to qualify products, channel training focusing on contractors and distributors, and providing reliable data to guide energy savings estimates. These efforts are starting to germinate.
The DLC recently released Networked Lighting Controls Specification V2.0, updating its first specification from May 2016. The DLC is recertifying systems for the Qualified Products List (QPL) for Networked Lighting Controls. As of August 2017, 19 systems from 15 manufacturers were listed. U.S. and Canadian utilities use DLC QPLs to qualify lighting products for rebate programs. In 2017, utilities began to either require QPL listing for networked controls or launch new rebates specifically designed around this technology.
V1.0 of the specification included “required” and “reported” capabilities. The DLC required and verified system capabilities including networking of lighting and controls, luminaire and device addressability, continuous dimming, occupancy sensing, daylight harvesting, and high-end trim, and zoning. Additionally, the system must be commercially available and protected by a five-year warranty covering all components in the specification.
Reported capabilities include luminaire-level control (integrated or nonintegrated); time scheduling, load shedding, personal, or plug-load control; localized processing (distributed intelligence); BMS/EMS/HVAC integration; energy monitoring; device monitoring/remote diagnostics; type of user interface; and operational and standby power.
Most notably, V2.0 built upon V1.0 by differentiating interior and exterior systems and identifying specific requirements for exterior systems, as they often have different requirements. V2.0 also allows reporting more system information, such as application program interface, color tuning, start-up and configuration requirements, and security information.
“Advanced and networked lighting control systems have long been a complicated and confusing topic,” said Gabe Arnold, technical director, DLC. “There’s been little standardization, a myriad of options, constantly changing technology, and constantly changing offerings from manufacturers. With this new QPL resource, we are providing a tool to help break through some of that confusion. Whether you are looking to identify simple, room-based wireless systems to use on your retrofit project, a comprehensive system with cloud-based control for an enterprise client, or even just to find a system that can dim a certain type of load, the QPL provides a resource.”
More than 20 rebate programs have adopted the QPL. Of these, about a dozen have developed new programs to promote the technology through a rebate adder. Current rebates typically encourage networked controls to be installed along with LED lighting.
For example, the Mass Save Performance Lighting Program in Massachusetts offers a rebate of $2/watt saved for projects that use DLC-qualified luminaires and exceed energy code. If at least 80 percent of the connected lighting is controlled by a DLC-qualified networked control system, the rebate doubles. Through its Lighting Systems and Sensors prescriptive rebates program, Mass Save offers up to $95/DLC-qualified LED luminaire when combined with a DLC-qualified networked control system.
Rebate programs are expected to grow as the DLC addresses market barriers such as estimating energy savings and a lack of familiarity in the channel, and utilities find effective ways to incorporate networked controls. The DLC was building a database of manufacturer- and utility-reported energy savings for projects in more than 120 buildings and published its first report in September. This database will help utilities confidently project energy savings needed to justify rebates.
Meanwhile, the DLC is developing channel training on networked lighting controls specifically aimed at ECs and distributors. The DLC is planning pilot training with several utilities in 2018 and aims to offer an interactive online training program by late spring.
“All indicators show that what’s coming from connected networked lighting controls in the next few years will be even more disruptive than what occurred with LEDs,” Arnold said. “We encourage distributors and contractors to work with their local utility or rebate program and take advantage of these new resources and prepare for what’s coming.”
Another day, another matchup between a lighting company and an IT firm in an effort to turn lighting infrastructure into intelligent data networks. This time, LED lighting stalwart Acuity Brands has teamed with LocusLabs, an indoor mapping software specialist which has provided wayfinding programs to major airports such as Dallas/Fort Worth International.
LocusLabs is enabling its “location as a service” technology to work with Acuity's Atrius, which is Acuity's catch-all brand of an ever-widening set of smart lighting and lighting-based Internet of Things (IoT) services.
Acuity already offers indoor positioning services (IPS) through Atrius, so LocusLabs adds another arrow to the Acuity IPS quiver. LocusLabs has already installed its technology at airports including DFW as well as Houston's George Bush Intercontinental Airport and William P. Hobby Airport, helping passengers call up maps on their phones that guide them to terminals and shops. The lights are not believed to be involved in those cases.
Atlanta-based Acuity said LocusLabs' LocusMaps application “powers navigation in hundreds of millions of mobile devices used at airports, retail malls, multi-floor buildings, and campuses, making it easy to search, discover, and navigate large, complex indoor spaces.”
That is just the sort of thing that Acuity itself claims to have already provided at last count at over 50 million ft2 of retail space, to help shoppers find their way around sprawling aisles, and to engage those shoppers with information and discounts sent to their phones.
For example, Acuity is providing smart lights to US retail giant Target, which recently said it will roll out lighting-based indoor positioning systems accessible through a Target app at nearly half of its 1800 retail stores by Christmas.
The lighting industry is pushing retailers and other building operators to embed location services into lights, thus taking advantage of an existing infrastructure and eliminating the need to construct separate networks of beacons that require their own maintenance and power. That logic was compelling to San Francisco-based LocusLabs.
“Through its Atrius IoT platform offering, Acuity Brands is incorporating location-based services into the fabric of buildings, and a ubiquitous solution is exactly what is needed going forward for an optimal user experience,” said Campbell Kennedy, LocusLabs CEO and co-founder. “By using Atrius IoT services and sensory network, LocusLabs' location-as-a-service software platform can deliver the most accessible solution in the market for all building stakeholders to leverage their smart building investment."
While the lighting and IT industries are increasingly working together in the smart building market, they are also competing against each other. Not all end users who deploy indoor sensors and communications chips will chose to embed them in the lighting. LocusLabs itself, for instance, has not always worked through lighting.
And when Barclays plc outfitted its London investment banking headquarters with sensors that track room occupancy, for instance, it mounted those sensors under employees' desks, and not in the lighting.
For location services, Acuity offers at least two different technologies. It will embed Bluetooth beacons into luminaires. It can also turn on a technology called visible light communications (VLC), which encodes data in the modulating light beams of an LED light source. A smartphone can pick up that data via the phone's camera.
Alliances between lighting vendors and IT companies are now happening on a regular basis. Last week alone, smart lighting company Gooee (which is really as much of an IT firm as a lighting outfit) gave an equity share to IoT cloud software company Evrythng, and lighting giant Osram bought a minority stake in retail software firm beaconsmind.
Source: LEDs Magazine
The world's largest known deployment of lighting-based indoor positioning is finally going full speed ahead, as US retail giant Target plans to roll out a customer engagement system in nearly half of its 1800 stores by Christmas.
Using Bluetooth chips embedded in LED ceiling lights from Acuity Brands, Target will send signals to shoppers' phones. Drawing on a Target app, the phones will display an interactive map that guides individuals around the aisles, helping them find specific items and providing information about discounts.
“This promises to make it easier than ever to find what you’re looking for, so you can fill up your cart and get on your way,” Target chief information and digital officer Mike McNamara said in a video blog on Target's website. “It'll even tell you if the product's on sale, so you never have to miss out on an opportunity to save.” He likened the system to driving a car using GPS.
Target has been piloting indoor positioning (IPS) for several years, as LEDs Magazine's sister publication Lux first reported exclusively back in April 2015.
But like many early indoor positioning implementations, Target has held back from full-on deployment. As of two years ago, it was trialing the technology in about 100 stores.
At the time, it was kicking the tires on different methods, including both Bluetooth wireless radio as well as something called visible light communication (VLC), which sends signals to phones via LED-generated lightwaves, rather than via radio frequencies.
The lights will not only illuminate, but will also help guide you and deliver information to your phone at hundreds of Target stores.
In a decision that will disappoint VLC advocates and which some observers will find surprising, the retail chain said it has decided to use Bluetooth but not VLC, a Target spokesperson told LEDs. He declined to elaborate, and Acuity would not comment.
It could be that improvements related to the recent ratification of a Bluetooth mesh standard convinced Target to choose the radio method. The mesh standard prescribes a common method for allowing Bluetooth chips to hand off instructions to each other, effectively extending the range of Bluetooth far beyond the 30 ft that it typically provides.
Bluetooth's disadvantage compared to VLC is that it is not as accurate — it can pinpoint a product's location on a shelf to within 2–3m (about 6.5–10 ft) versus VLC's 30 cm, which is less than a foot.
But one of VLC's drawbacks is that it requires a user's phone to constantly point to the ceiling lighting, because lightwaves have to hit the phone's camera in order for the technology to work. In contrast, Bluetooth does not require line of sight for such Internet of Things (IoT) applications.
Another downside for VLC in indoor positioning projects is that lights have to always be on. That means VLC would often not function in a store or mall with plenty of natural light — say, one with a glass atrium and skylights — unless the lights were switched on when they don't have to be for traditional illumination purposes. That's one reason why Philips Lighting, a pioneering VLC enthusiast, is now using Bluetooth as well, and in some instances combining the two technologies.
Target is embedding Bluetooth transmitters in Acuity ceiling lights, the Target spokesperson said, noting that the system will only work with iPhones at first. Android support will follow later.
The rollout at Target could help boost the lighting-based IPS concept and encourage further takeup of the IoT scheme, which has been characterized by one-off implementations in single or small groups of stores — such as at an EDEKA Paschmann store in Dusseldorf and E.Leclerc store in Langon, France; at the Dubai-based retail chain aswaaq; a Carrefour store in Lille, France, and elsewhere.
As of last July, Acuity itself claimed to have deployed lighting-based indoor positioning in over 50 million ft2 of retail space, although it has been reticent about naming its users. Its trials are believed to include Walmart.
Acuity has been steadily building its indoor positioning arsenal. It picked up VLC technology when it acquired VLC specialist company ByteLight in 2015. ByteLight had been working with GE prior to the acquisition. Acuity also uses VLC technology from Qualcomm called Lumicast, and, as LEDs has reported, Acuity has used the former ByteLight team to help integrate VLC and Bluetooth into one system (if that combination exists in the Bluetooth-led system at Target, no one is saying).
Last spring, it launched a systems integration program inviting partners to help develop indoor positioning and other indoor IoT programs such as asset tracking. It also launched a Bluetooth system that tracks shopping carts around stores in order to provide retailers with information on floor traffic and also to keep tabs on the carts' whereabouts.
It's all part of push by lighting companies to morph more into information technology companies, and to develop offerings that collect data, which can then be monetized in many ways, such as by offering promotions and discounts to the IoT application users.
There is the question of whether shoppers even want guidance on their phones as they navigate around physical-world stores.
Another issue that has possibly held back indoor positioning schemes is that they raise security and privacy concerns. With that in mind, Philips Lighting left personalization out of a recent implementation at the four-story Media Markt computer and electronics shop in Eindhoven.
The lighting industry also faces another challenge: Even as more large end users such as Target decide to deploy, those users might buy from a more conventional IT supplier rather than from a lighting company.
For example, Barclays plc has deployed sensors to help monitor office usage at its investment banking headquarters in London, without embedding those sensors in lights.
For reasons like that, lighting company Osram now has a business selling Bluetooth chips, such as when it provided a retail chain with Bluetooth hardware to connect to non-Osram lights for a system at Guess and Marc O'Polo fashion shops in Switzerland.
Likewise, smart lighting specialist Gooee last year teamed with Israel's PointGrab Ltd. to tie that company's CogniPoint wall-mounted sensors into the Gooee cloud data analysis system.
Source: LEDs Magazine
ANN ARBOR—In an advance that could boost the efficiency of LED lighting by 50 percent and even pave the way for invisibility cloaking devices, a team of University of Michigan researchers has developed a new technique that peppers metallic nanoparticles into semiconductors.
It's the first technique that can inexpensively grow metal nanoparticles both on and below the surface of semiconductors. The process adds virtually no cost during manufacturing and its improved efficiency could allow manufacturers to use fewer semiconductors in finished products, making them less expensive.
The inside of the main concourse of the molecular beam epitaxy apparatus, which University of Michigan engineering researchers used to make the advanced nanoparticle-infused gallium nitride semiconductors. The semiconductors could boost LED efficiency by up to 50 percent, and even lead to invisibility cloaking devices. Image credit: Joseph Xu, Michigan Engineering
The metal nanoparticles can increase the efficiency of LEDs in several ways. They can act as tiny antennas that alter and redirect the electricity running through the semiconductor, turning more of it into light. They can also help reflect light out of the device, preventing it from being trapped inside and wasted.
The process can be used with the gallium nitride that's used in LED lighting and can also boost efficiency in other semiconductor products, including solar cells. It's detailed in a study published in the Journal of Applied Physics.
"This is a seamless addition to the manufacturing process, and that's what makes it so exciting," said Rachel Goldman, U-M professor of materials science and engineering, and physics. "The ability to make 3-D structures with these nanoparticles throughout is going to open a lot of possibilities."
The key innovation
The idea of adding nanoparticles to increase LED efficiency is not new. But previous efforts to incorporate them have been impractical for large-scale manufacturing. They focused on pricey metals like silver, gold and platinum. In addition, the size and spacing of the particles must be very precise; this required additional and expensive manufacturing steps. Furthermore, there was no cost-effective way to incorporate particles below the surface.
Former materials science PhD student Sunyeol Jun prepares the molecular beam epitaxy apparatus that’s used to make the nanoparticle-infused gallium nitride semiconductors. The semiconductors could boost LED efficiency by up to 50 percent, and even lead to invisibility cloaking devices. Image credit: Joseph Xu, Michigan Engineering
Goldman's team discovered a simpler way that integrates easily with the molecular beam epitaxy process used to make semiconductors. Molecular beam epitaxy sprays multiple layers of metallic elements onto a wafer. This creates exactly the right conductive properties for a given purpose.
The U-M researchers applied an ion beam between these layers—a step that pushes metal out of the semiconductor wafer and onto the surface. The metal forms nanoscale particles that serve the same purpose as the pricey gold and platinum flecks in earlier research. Their size and placement can be precisely controlled by varying the angle and intensity of the ion beam. And applying the ion beam over and over between each layer creates a semiconductor with the nanoparticles interspersed throughout.
"If you carefully tailor the size and spacing of nanoparticles and how deeply they're embedded, you can find a sweet spot that enhances light emissions," said Myungkoo Kang, a former graduate student in Goldman's lab and first author on the study. "This process gives us a much simpler and less expensive way to do that."
Researchers have known for years that metallic particles can collect on the surface of semiconductors during manufacturing. But they were always considered a nuisance, something that happened when the mix of elements was incorrect or the timing was off.
"From the very early days of semiconductor manufacturing, the goal was always to spray a smooth layer of elements onto the surface. If the elements formed particles instead, it was considered a mistake," Goldman said. "But we realized that those 'mistakes' are very similar to the particles that manufacturers have been trying so hard to incorporate into LEDs. So we figured out a way to make lemonade out of lemons."
Former materials science PhD student Sunyeol Jun prepares the molecular beam epitaxy apparatus that’s used to make the nanoparticle-infused gallium nitride semiconductors. The semiconductors could boost LED efficiency by up to 50 percent, and even lead to invisibility cloaking devices. Image credit: Joseph Xu, Michigan Engineering
Toward invisibility cloaks
Because the technique allows precise control over the nanoparticle distribution, the researchers say it may one day be useful for cloaks that render objects partially invisible by inducing a phenomenon known as "reverse refraction."
Reverse refraction bends light waves backwards in a way that doesn't occur in nature, potentially directing them around an object or away from the eye. The researchers believe that by carefully sizing and spacing an array of nanoparticles, they may be able to induce and control reverse refraction in specific wavelengths of light.
"For invisibility cloaking, we need to both transmit and manipulate light in very precise ways, and that's very difficult today," Goldman said. "We believe that this process could give us the level of control we need to make it work."
The team is now working to adapt the ion beam process to the specific materials used in LEDs—they estimate that the higher-efficiency lighting devices could be ready for market within the next five years, with invisibility cloaking and other applications coming further in the future.
The study is titled "Formation of embedded plasmonic Ga nanoparticle arrays and their influence on GaAs photoluminescence." The research was supported by the National Science Foundation through the Materials Research Science and Engineering Center at U-M.
Source: Nanoparticles could spur better LEDs, invisibility cloaks
Wired lighting infrastructures have a history of providing dependability that, until recently, wireless networks couldn’t match. And while there are other benefits to installing a wired network, many of today’s wireless platforms—especially those supported by a Bluetooth® mesh network—ensure greater flexibility and extensibility at a reduced cost.
Wired vs Wireless
Advancements in wireless connectivity make it hard to justify choosing a wired infrastructure over a wireless platform. An argument could be made that wired networks still offer better reliability, but installation costs, for both materials and labor, are significantly higher. On top of the added expense, there’s also a greater chance of disruption to day-to-day operations when deploying or upgrading a wired system, especially in highly active commercial or industrial environments. A wireless network provides significant cost savings with minimal disruption during deployment.
Additionally, a wired network is a concrete part of a building’s infrastructure and does not scale easily. Upgrades often require new component installs to improve performance, and in some cases, an entire rip and replace of the existing system is necessary. Wireless platforms are easier to install and upgrade, offering the flexibility you need to respond quickly to changing business demands.
Commercial Lighting and Bluetooth Technology
A wireless platform supported by a Bluetooth mesh network allows a system, such as lighting, to provide additional capabilities beyond its primary use, offering greater overall value and ensuring a higher return on investment. “It may be necessary to integrate a lighting system with various types of sensors in the building,” said Martin Wooley, technical program manager, Bluetooth Special Interest Group (SIG). “It’s possible to achieve this with wired systems, but often this requires separate control equipment to orchestrate sensor and lighting behaviours. Bluetooth mesh was designed to address problems of this sort…, specifically with commercial lighting systems in mind.”
Bluetooth mesh networking is a full-stack solution designed for commercial lighting applications and includes features specific to a wireless lighting platform. In James O Malley’s recent Gizmodo UK article outlining six reasons why Bluetooth mesh will make a big impact, he talks about the versatility of a Bluetooth mesh network when used for lighting. Malley explained, “…if you have a home or a workplace where every light-bulb is Bluetooth enabled, this doesn’t just mean you have smart lighting… you have in fact built a building-wide Bluetooth network blanket, which can talk to every other Bluetooth device in the building.”
In addition to supporting common lighting requirements, a Bluetooth mesh network can include fully integrated non-lighting features, such as sensors. In Wooley’s technical paper, Bluetooth Mesh Networking: Paving the Way for Smart Lighting, he illustrates examples of lights that can act as Bluetooth beacons, allowing smartphone apps to help visitors find their way around a building. Or a lighting system that can collect a range of data from building sensors, making it available for analysis and real-time use.
“The more interesting and potentially substantial opportunity, which a Bluetooth mesh lighting system offers, is that installing such a system equips the building with a wireless network and creates a distributed platform for other wireless building services,” said Wooley. “Lights and switches are microcontrollers with a Bluetooth mesh communications capability and software which controls what those devices can do. Software can be upgraded and added to, so new capabilities…can reside within the lighting system.”
Designed with Lighting in Mind
The Bluetooth mesh network specification provides an innovative wireless solution for commercial lighting. It offers reliability that is functionally equivalent to that of a wired system, but with the added responsiveness, scalability, and extensibility that you can only get from a wireless solution. "Bluetooth mesh networking is the most robust and powerful low-power radio technology for connected lighting in commercial spaces,” said Rafal Han, CEO, Silvair.
Combine that with the multi-vendor interoperability, low power, and low latency of a Bluetooth Low Energy (LE) stack, and you get a comprehensive lighting system that also serves as an industrial-grade platform for distributed wireless building services. This enhances operational efficiency and creates a flexible network infrastructure that can adapt to changing business needs.
Source: Bluetooth Mesh Shows Wireless Connectivity in a Whole New Light
Industrial-strength savings: Michigan companies take steps to reduce energy used in industrial, office facilities.
Greg Pflum was hoping to lure a new plant to the BASF facility he oversees in Wyandotte four years ago when he got an unwelcome reminder about the importance of energy costs.
High Michigan energy prices made the site uncompetitive, said Pflum, the vice president and general manager of BASF Corp.'s Midwest Regional Hub. "I want to grow our business, (so) we have to be competitive."
The plant would have brought 100 jobs to Wyandotte. Instead, BASF decided to build it outside of the United States.
It's one dramatic example of the role energy costs play in business decisions, and why they are leading companies across Michigan are taking steps to reduce the amount of energy used in industrial and office facilities.
At the BASF facility Pflum runs, recent energy-saving measures have played a part in the addition of about 100 new jobs a year, he said, estimating energy accounts for about 5 percent of overall operating costs.
Pflum's team is keeping costs down by:
Last year, when a BASF facility in Southfield Pflum oversees needed a new roof, crews installed a polyurethane material that has reduced building energy use by 5 percent to 10 percent, he said.
In Wyandotte, a new steam operation, used to heat buildings and power manufacturing, is estimated to save about $1 million a year, Pflum said.
"It doesn't take long to justify the investment," he said.
Across the state, office furniture maker Steelcase Inc. also has an eye on energy savings.
"In the office furniture industry, we compete on sustainability," said John DeAngelis, energy and special project manager for the Grand Rapids company. "It's important to our customers."
In early 2016, Steelcase gained significant energy savings by relighting a 1-million-square-foot distribution center in Kentwood.
That one project reduced the company's global energy bill by 2 percent, DeAngelis said.
"For a company with operations all over the world, that's a huge impact," he said. "We saved hundreds of thousands (of dollars). It paid itself back in less than two years."
The relighting allowed Steelcase to zone areas of the facility — meaning it can light some areas and shut down or reduce lighting in areas where it isn't needed.
Steelcase did a similar project at its Caledonia wood plant, where desktops and cabinets are produced. A wireless control system allows Steelcase to turn lights down or off — even from offsite.
"We constantly change the layout of our plants," DeAngelis added. "You can control those lights without having to make any physical changes (to the way they're configured)."
Steelcase also uses energy-efficient LED lighting and controls in its office buildings and asks security staff on night rounds to double as energy auditors — making sure fans and TVs are off.
Another Michigan company leading the way in energy-use reduction is Gibraltar's HyCAL Corp. The company won a Governor's Energy Excellence Award for its 18-month conversion of a 1950s-era portion of the former McLouth Steel site to a modern, energy-efficient factory.
"This was just a metal building with holes in it," said HyCAL General Manager Steve Swan, whose company will produce high-strength steel for auto industry. "We did a complete renovation and basically turned it into a new building."
The $15 million renovation on the 550,000-square-foot factory included new siding, roofs and insulation, as well as installation of energy-efficient doors and 650 LED lights. By making the building airtight, HyCAL eliminated the need for heating units.
"We are using the heat from our process to heat the building," Swan said. "Before, it was all going outside."
Swan, who estimated that 30 percent of HyCAL's operating costs go to energy, said those costs would have been 10 percent higher without the renovations.
"By spending money now, we're (reducing) cost later," he said.
That mindset is in place across the state, as businesses look to shift available dollars from energy bills to other parts of their operations, said Dan Scripps. Scripps is president of the Institute for Energy Innovation, a nonprofit that aims to makes a business case for energy savings, and vice president of the Michigan Energy Innovation Business Council, a trade group that includes including wind, solar and other companies.
"We see significant savings in energy efficiency," Scripps said. "It means businesses are more competitive at the end of the day."
Companies are finding savings in everything from using better HVAC systems and energy-efficient lighting to using increasingly affordable renewable energy. Solar panels, for example, cost 1 percent of what they did 25 years ago, he said.
Some companies are forging deals with utilities to reduce their power use during peak times.
"If you've got some flexibility in when you use energy, that can be a huge savings," Scripps said.
Businesses may take their industrial operation offline for 15 minutes or shut down office air conditioning for a short time — or temporarily allow utilities to reduce their power supply. Not only do companies realize savings when not using power, but utilities also provide them a lower rate throughout the year for cooperating.
Utilities benefit because reduced power load demand means they don't have to fire up another generation station, Scripps said.
They also benefit because of a 2008 law that requires them to hit energy-use reduction targets, said Dave Walker, a public utilities engineer for Michigan Public Service Commission, which regulates utilities.
Adds Patricia Poli, manager of MPSC's Energy Waste Reduction Section, "They entice customers with rebates. The customer gets a discount, and the utility gets to claim the savings. If it delays the need to build a power plant, because you're offsetting increases in demand, everyone benefits."
To assist businesses seeking to improve their energy-inefficient buildings, the State of Michigan passed the Property Assessment Clean Energy act in 2010, also known as PACE. However, few companies have taken advantage of it so far.
"It's been slower than I hoped," said Andy Levin, president of Detroit-based Lean and Green Michigan, which administrates the program for 32 local governments and 22 counties. "It's just getting started."
Businesses that do an energy audit on a building may opt not to fix leaks, because of the cost and a long payback time, he said.
Through the PACE program, a business can get a loan for up to 20 years that is secured by a special tax assessment on the building. Lenders feel more secure, because failure to pay the assessment can lead to foreclosure.
"If you don't pay them, the county sheriff is going to come take your hotel," Levin said.
If the project cost is $250,000 or more, a contractor has to guarantee energy savings will be greater than cost, Levin said. If the savings fall short, that contractor has to write a check or fix the problem, he said.
While businesses have completed only a handful of PACE projects — about $3 million to $4 million worth — they've run the gamut from a manufacturing facility to a beer distribution operation to apartment buildings.
"We've had every kind of energy efficiency (upgrade) — windows, bay doors, wall insulation, roof insulation," Levin said. "Almost everyone includes lighting — LED lighting."
Levin said he expects the program to include more than $100 million in projects annually once it catches on.
"It's going to be very big," he said.
Two recent projects are an overhaul of The Whitney restaurant in Detroit, housed in a 19th century mansion, and an office building in Clinton Township. They are the first PACE projects to be financed in Wayne and Macomb counties.
Pension funds and private equity funds are supplying the money for PACE projects, said Bob Mattler, who recently started Green Portfolio Solutions LLC of Bloomfield Hills to arrange the deals.
"It provides an owner the ability to upgrade his building with nothing out of his pocket," he said. "If you can save 25 to 30 percent or more on your electric or gas bill, you can pay off the loan with those savings."
Building owners can get an interest rate of 5 percent to 7 percent and are not prohibited from selling the building, he said. The assessment is assumed by the next owner.
"Here in Michigan, we have so many old buildings, and we always need capital to improve them," Mattler said.
Source: Crain's Detroit Business
New nLight® AIR Wireless Controls from Acuity Brands Reduce Complexity and Cost of LED Retrofit for Building Owners and Contractors
Acuity Brands, Inc. (NYSE: AYI) today announced the nLight® AIR platform, a wireless extension of its widely deployed nLight® digital lighting control platform. As a fully wireless lighting control system with a five-tier security architecture, nLight AIR is ideal for building owners and contractors looking to seamlessly upgrade facilities to LED lighting control solutions that are designed to support compliance with state energy code requirements. nLight Air is especially suited for spaces where wiring is cost prohibitive, or for retrofits where running new wires can be difficult or complex.
The nLight AIR control system consists of nLight AIR enabled LED luminaires (equipped with eldoLED® LED drivers), wireless battery powered wall switches and a mobile configuration app, CLAIRITY™, for quick and easy startup. nLight AIR systems are deployed using the building’s existing wiring, which reduces installation costs and accelerates payback.
“Commercial lighting integration suffers all too often from a fragmented approach with disparate systems, software and networks that make installation and maintenance cumbersome and costly,” said Audwin Cash, Vice President, Acuity Controls. “nLight AIR is designed to be contractor-friendly, with a consistent, simplified installation and start-up procedure, a single interface into the network and an intuitive mobile app which can be used to configure the system. Combining the nLight AIR control system together with Acuity’s long-life LED luminaires offers facility managers, building owners and electrical contractors with a solution that can provide energy savings for years to come.”
This new wireless lighting control solution represents significant advancements in lighting system technology:
Last week we mentioned the possibilities of wireless mesh controls integrating with LED light
fixtures. When the time comes that we are able to offer lighting options like this on a large
scale, the energy savings and environmental impact could be quite significant. Last Thursday
(August 3, 2017), an article came out that discussed a current application, in southern Holland
(yes - across the pond), at the Chemelot Industrial Park in Geleen. One top priority of the
conversion from fluorescent lighting to wireless mesh controlled LED lighting was to be able to
control the 17,000 outdoor lights to either turn on or off and/or increase or decrease the lumen
output when and where it is necessary. Now that is awesome!
The article that I am referring to is “Wireless mesh controls augur huge savings, slash light
pollution at Dutch chemical plant” Published on August 3, 2017, By Mark Halper, Contributing
Editor, LEDs Magazine, and Business/Energy/Technology Journalist. The article states:
“The new ability to turn lights off and to dim them augurs enormous savings in electricity and
CO 2 emissions. It should also drastically reduce light pollution…The combination of the LED
luminaires and the wireless mesh controls should also slash maintenance costs, given the
expected long life of the LEDs as well as the modules' ability to monitor the performance of the
“Because we 'switch' the lights with software, dimming and switching is now possible,” said Han
Bak, CEO of Haarlem-based Chess Wise, the company providing the mesh technology which it
calls MyriaMesh [Chess Wise is one of several lighting-related companies involved in a one-for-
one replacement of existing fluorescent luminaires with LED models in a 15-year service-based
scheme]. “The main thing is the lights are only on when you really need light, which is
completely the opposite of the existing situation, when the lights were on 24/7.”
“MyriaMesh uses Bluetooth radio chips, but Chess Wise deploys its own proprietary radio-
agnostic mesh protocol, rather than using the recently ratified Bluetooth mesh standard. Chess
Wise builds modules that operate at either 868 MHz or at the Bluetooth frequency of 2.4 GHz,
as it has done for Chemelot.
Bak said Chess Wise is considering a Bluetooth mesh version to support customers who might
prefer it. Different requirements would benefit from different protocols. For example,
MyriaMesh might work better when signals have to travel longer distances between luminaires.
Chemelot's 17,000 lights are an apt fit with the MyriaMesh brand name, as “myria” literally
means a unit of 10,000.”
We will keep our eyes out for more examples and do our best to keep you updated on the
progress of Bluetooth mesh and LED lighting.
http://www.ledsmagazine.com/articles/2017/08/wireless-mesh- controls-augur- huge-savings-
slash-light- pollution-at- dutch-chemical- plant.html
Last month the Kirkland, WA based Bluetooth Special Interest Group (SIG), the organization that
oversees Bluetooth wireless communication protocols, agreed to and published a set of specifications
that created a standard that will allow us to integrate smart lighting controls to cover large areas - even
when we mix products from different lighting manufacturers. An article, published a couple of weeks
ago, titled, “Bluetooth’s range just widened, and IoT lighting companies are thrilled”, published on July
18, 2017, by Mark Halper, Contributing Editor, LEDs Magazine, and Business/Energy/Technology
Journalist, opened our eyes to just how important this agreement may be to future LED lighting
“After at least two years of internal wrangling and difficult technology choices, the Kirkland, WA-based
Bluetooth Special Interest Group (SIG) ratified a means to mesh together Bluetooth beacons, allowing
them to hand off instructions to each other. The move effectively boosts Bluetooth's reach far beyond
the 30 feet that is typical for the Bluetooth that consumers commonly use to share things like audio files
among smartphone, computers, tables, TVs, and other devices.
“We just completed a several-year effort of completing a set of specifications that define a standardized
approach for creating true industrial-grade mesh networking solutions using Bluetooth technology,”
Bluetooth SIG vice president of marketing Ken Kolderup said in a phone interview with LEDs Magazine.
“Now there's a standard way that defines how mesh networking gets done on Bluetooth, so that all
the vendors can now create interoperable solutions.”
Now that, potentially, clears a lot of road blocks, especially for organizations, like retail stores,
warehouses and commercial offices, that choose to upgrade their lighting to LED over the course of time
and prefer to control them all from a single point or device. “There was some real work to do; it's very
demanding, especially for a commercial environment,” said Bluetooth SIG's Kolderup, who noted that it
took time to work out details related to reliability, scalability, performance, latency, security, and other
aspects. The SIG also performed extensive interoperability testing to assure the best chance of all
Bluetooth devices — the SIG has 32,000 members — working together in any scenario. For example,
“We need to make sure that a switch you buy today can work with a light bulb you buy from a vendor
that may not even exist today, 20 years from now,” he noted.
Now that is truly working together to accomplish a goal that will benefit us all. For more information, or
to read the complete article, please click on the link below.
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