In the future, personalized lighting will interact with our presence, our environment and our activities. Lighting will change color, brightness and directionality, all the while transmitting data to our cellphones and wearable tech, networked with the Internet of Things (IoT). Implementing this vision is the purpose of the Smart Lighting Engineering Research Center, newly rebranded as the Lighting Enabled Systems & Applications Engineering Research Center (LESA ERC).
ERCs are interdisciplinary academic research partners working together to accelerate the commercialization of advanced technologies, with the support of industry. LESA is led by Rensselaer Polytechnic Institute (RPI) and Director Robert F. Karlicek, Jr. In the next few years, LESA will conclude its 10 year cycle as a federally funded National Science Foundation ERC, and then continue to develop advanced technologies as they are commercialized in the new lighting landscape.
LESA’s strategic plan is to propel twenty-first century lighting: not just LEDs, but the advanced sensors and adaptive control architectures that enable human-centric lighting in a smart environment. Research partners include Boston University (BU), focusing on visible light communications (VLC); the University of New Mexico (UNM), which is developing advanced sensor technologies; and Thomas Jefferson University, where Dr. George (Bud) Brainard continues his research on light and circadian effects. RPI Senior Research Scientist Tessa Pocock leads research in adaptive horticultural lighting.
Steven R.J. Brueck is a LESA associate director and a distinguished professor emeritus at UNM. As LESA transitions toward a more-industrial funding model, he highlights the plenoptic sensors with CMOS communications being developed at UNM.
“We have strong interaction with a number of different companies, particularly in commercializing some of the advanced sensor technology,” Brueck said. Plenoptic sensors capture the light field: spectrum, intensity, polarization and incident angle of light. Early commercialization might be in miniaturized light meters and colorimeters/spectrometers, according to Brueck.
Lighting for big data
LESA’s industrial advisory board includes familiar names like Philips, OSRAM Sylvania, GE/Current, Acuity Brands, Crestron and Lutron. But these sensors are of interest to additional LESA Industry Members like ABB, which is involved in building automation and smart cities, or ams, a leading sensor company that is pursuing smart lighting. “Big lighting companies are trying to reposition themselves as value-added service providers. The IoT future requires sensors and sensors need power, and the only system that has power everywhere is lighting,” explained Karlicek. “It’s all about using lighting systems to generate data.”
According to Tom Griffiths, senior marketing manager, Sensor Driven Lighting at ams, a network of sensors provides awareness to a building management system and the IoT. “This is the very beginning stages of what we call ‘connected smart lighting.’ The value of connected smart lighting is realized in increasing granularity of control, personalization and efficiency. It’s all about enabling the Internet of Things with detailed real-time information about the spaces we occupy.” He used Google Maps as an example where aggregation and mining of collective data provide benefits (traffic information) that come back to the user.
Task tuning, daylight harvesting and occupancy detection are just the beginning. When occupant data is collected and analyzed, light output can be optimized, maximizing energy efficiency and user comfort. As an example, by measuring in-home activity patterns, elderly or disabled people could be able to live independently longer in their own homes. Adding personal identification, e.g., RFID chip or other wearable device, can enhance light-based indoor navigation in a crowded hospital or mall. “For the future in the built spaces that we live in, everybody’s data flows to the cloud and returns services, information and increased personalization,” Griffiths said.
VLC – sometimes called Li-Fi – may make lighting the keystone of the IoT. Li-Fi modulates multiple LED chips of different, narrow spectra at speeds much faster than the human eye can resolve. UNM’s plenoptic sensors will be used in applied VLC research in Boston. BU has set goals for high data transmission rates with low interference. LESA’s Li-Fi lead, Associate Director Tom Little at BU, sees that growth in demand for wireless communication, particularly mobile video, will overwhelm improvements in Wi-Fi. IDC Research predicts that by 2020 there will more than 30 billion devices connected to the IoT, with sensors soon to number in the trillions.
LESA will continue to seek federal funding for its initiatives, and human-centric lighting continues to be a hot topic. The National Institutes of Health is already funding research on lighting and circadian regulation. NASA and the Department of Defense continue to have “an obvious synergy of interests,” according to Brueck.
Studies of human circadian patterns of alertness show that the blue end of the visible spectrum helps regulate melatonin cycles that impact human sleep, along with a range of biological and behavioral responses. “The key here is that, while the role of blue light in governing human melatonin production is well known, what we don’t have is the precise control mechanisms that allow us to more precisely help people manage their wake-sleep cycles – which are complex. LESA research is developing control models that allow us to use biofeedback to quickly and precisely estimate a person’s circadian phase, and then help shift it appropriately by changing the lighting spectrum,” said Karlicek.
Rensselaer researchers combined multiple smart lighting strategies in LESA’s Smart Lighting Conference Room. LED troffers with RGBAW tunable sources are combined with networked light field sensors and time-of-flight sensors. Time-of-flight sensors use light to measure distances between objects in real time: mapping occupants’ activities in 3D without cameras. Together, the networked sensors record daylighting and electric lighting along with occupancy and room usage. The luminaires adjust accordingly; each is an IoT node.
Truly adaptive lighting and daylighting systems optimize space performance by automatically adjusting light output – illuminance, distribution patterns and colors – based on signals from the environment. One goal for the conference room test bed is an automated self-commissioning algorithm, using decentralized feedback, that combines optimization and plug-and-play capability. “Looking to the future, lighting systems are going to have embedded intelligence, because mere mortals won’t be able to control the systems with all the inputs and options,” said Karlicek. “The lighting expertise is embedded in network, with distributed processing and control.” LESA’s tag line is “Lighting Systems that Think.”
The conference room’s test-bed architecture has been exported to the University of New Mexico Health Sciences Center (UNMHC) to investigate the effects of lighting on sleep patterns and healing in a hospital setting. Patients with depression, Parkinson’s disease, dementia and other neurological disorders have been shown to respond to light therapies of specific spectrum, intensity and timing/duration. The UNMHC test bed will study the effect of light therapies delivered by controlling room lighting, adjusting the intensity and color spectrum continually.
“Light box treatment is characteristically done during a short period of the day; generally 30 minutes where the individual sits in front of a light box,” said Dr. Lee Brown, medical director of the UNM Health Systems Sleep Disorders Center. “The new paradigm that we are testing is that we’ll be able to expose individuals over the course of days or weeks at a time to a prescribed regimen of lighting that over the course of the day can vary automatically in intensity and spectrum. In certain situations there are data to suggest that if you can simulate the changes in lighting intensity and spectrum that normally occur out of doors – to which we evolved over thousands of years – that we might be able to achieve more significant effects on patients with a variety of sleep-wake problems and other medical problems.”
Brown’s sleep disorder studies are first in line. It’s common for adolescents and young adults to be “night owls,” suffering from delayed sleep-wake phase syndrome. According to Brown, light box therapy in the morning resets the circadian clock, but students’ exposure to cellphones, tablets and computer screens late in the day can negate the therapeutic effects. “In the [hospital test bed] room, first of all, access to smartphones and computers and television will only be devices that have had their spectrum altered to not affect the individual’s internal clock. And second, the lighting regimen from the smart lighting in the room will be programmed so it starts out with an emphasis on bright blue light, and then toward afternoon and evening it will shift to more reddish, and then in the evening a much more dim, reddish light.” The hope is that simulating the entire cycle of natural lighting will provide a persistent therapeutic effect.
“This could change the whole lighting paradigm for hospital settings. The disruption in circadian rhythm in inpatients occurs because they’re cooped up in a room with fixed artificial lighting. If you were to equip inpatient rooms with smart lighting, you might improve their ability to sleep better and promote healing. It might be especially important in intensive care units where lots of other factors disrupt sleep and circadian rhythms…. Anything we can do to counter these other effects will hopefully be a benefit.”
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