Until recently, lighting systems operated as localized points of illumination. This purpose, however, is evolving as our dependency on connectivity and data continue to increase. Connected lighting systems (CLSs) blend light-emitting diode (LED) capabilities with Internet of Things (IoT) connectivity to enable design engineers to provide illumination and to transfer data simultaneously. With IoT as its data-collection platform, CLS will save electrical energy while opening up new gamuts of services and benefits for people and organizations.
At the core of CLSs is an emerging optical wireless communication technology called Li-Fi, which is short for light fidelity. Introduced in 2011, Li-Fi uses IEEE 802.11 protocols and has gained momentum toward becoming a viable alternative to the ever-shrinking Wi-Fi spectrum and toward making lighting a central point in smart infrastructure. This article explores the role of IoT technologies, Li-Fi’s ability to transfer data through lighting, and technologies that need further development to bring CLSs to their potential.
The Role of IoT
The explosion in IoT is a technological revolution. Smart sensor technology and wireless connectivity have led design engineers to focus on how to sense and collect data as well as how to get it into a digital domain for Web handling and manipulating. Sensors, connectivity, and digital data make up the foundation for further CLS development:
Sensors are everywhere, measuring aspects like humidity, temperature, pressure, air quality, vibration, and volatile organic compounds (VOC), to name a few. Sensors detect analog signals generated from the physical world and then convert them into digital data signals that can undergo control and manipulation by embedded systems (Figure 1). Optical sensors convert light energy into readable electrical signals that can detect whether lights are on or off and detect light intensity.
Wi-Fi is a technique that allows devices to connect to a wireless local area network (WLAN). Wi-Fi uses electromagnetic radiation in the radio frequency (RF) spectral range (20kHz–300GHz), at five primary frequency ranges: 2.4GHz, 3.6GHz, 4.9GHz, 5GHz, and 5.9GHz. Currently, most consumer products focus on one or both of the 2.4GHz and 5GHz frequencies. Wi-Fi has drawbacks, however, including a susceptibility to hacking and a spectrum that’s already nearing capacity.
Digital data is in an easy form to store for future use. Combined with a future where artificial intelligence (AI) and Big Data Analytics (BDA) curate, apply, extend, and leverage this data, the design aim is to bring illumination systems into this overarching technological framework. IoT promises to enable a variety of end-to-end solutions that are more intelligent.
Li-Fi: Optical Wireless Communication
CLSs blend LED capabilities with IoT connectivity with the goal of enabling design engineers to provide illumination and to transfer data simultaneously. At the core of these systems is solid-state lighting (SSL), which is lighting that uses LEDs as sources of illumination, rather than filaments, plasma, or gas. LEDs offer designers a palette of options, such as quick modulation between on and off and the ability to control colors and output lumens. They’re also known to be long-lasting, compact, durable, and energy efficient, which make them a good basis for expanded uses.
As an optical wireless communication (OWC) technology, Li-Fi has evolved to deliver data via visible light. Whereas Wi-Fi uses radio waves to deliver data, Li-Fi uses infrared, ultraviolet, and visible light waves, which offer several advantages. Whereas the Wi-Fi spectrum is crowded to the point of nearing crisis, the visible Li-Fi spectrum is nearly 10,000 times larger than its RF counterpart. Li-Fi can also offer data rates that are competitive with Wi-Fi, with reliable, high-quality transmission speeds up to >30Mbps. What’s more, Li-Fi uses Line of Sight (LoS) architecture, which makes it highly immune to hacking; data usually disappears when a hacker intercepts the data stream.
An LED’s ability to modulate on and off quickly is key to why Li-Fi works: Data moves from one location to another through these modulation and demodulation schemes. Li-Fi operates by taking streaming data content and inserting it into an SSL driver. This SSL driver can run a string of LED lamps, turning them on and off at high speeds. As the LED lamps turn on and off, strobing faster than the eye can see, they illuminate the area of context.
Within this area is a Li-Fi dongle, an integrated device that connects to a computer and contains a photodetector to sense the light. It responds by producing an electric current in proportion to the amount of light impinging on its surface. The tiny electrical signal passes into an electronics circuit with amplifiers that boost the signal. Further signal conditioning and processing occur before the signal leaves the dongle through a wireless connection to a device, such as a laptop, portable computer, mobile device, or mobile phone.
A Unified Whole: Products, Systems, and Software
Several years ago, LED manufacturers began prioritizing the creation of a unified solution—that is, lighting capable of interacting with all the various electro-mechanical systems in one place. With the boom in IoT, this initiative revealed three levels of differential, sustainable support necessary to enable the potential of CLSs using hardware, IoT, software, and interface assets.
Hardware assets require the packaging of LED components and the use of electronic drivers to control the current that passes to the LED components. Designers also must consider the related electro-optical-mechanical functions to see the realization of these devices and transform them into successful luminaries. Hardware designs may require thermal heat sinking, mounting, packaging, optical control, and integrations with items with which the luminaire will be interfacing (using common and applicable design codes).
Adding intelligent sensors to obtain analog information and convert it into digital information is also part of this design effort. In short, the suppliers should focus on how all the related hardware components will work together.
Hardware, however, is not enough. A robust CLS design requires additional measures to enable it to connect to and work in synergy with other lighting systems successfully. CLS suppliers must address system integration issues, including data security. How will data be secure from unauthorized users that attempt to take control? Data security may require authentication work. Authentication protects sophisticated keys that authorize access. Back-end storage, computers servers, and analytics also require thought. When entering the realm of IoT, CLS designers must ensure that the pathway to get data onto and off the CLS is available, reliable, and robust.
IoT provides a broad array of services never possible before by way of the cloud. In the new world of IoT, CLS providers that provide cloud-based technology services to support their offerings will have a competitive advantage because they will allow their customers to obtain the maximum benefits from their products immediately.
Future interoperability is paramount to fast growth. Standard solutions, which allow multiple suppliers’ products to work seamlessly together over time, provide economic incentives and benefits. Solutions that cannot work well with other products will find themselves at a competitive disadvantage, as the need to be able to cross domains and boundaries without issues will be primary.
Another area that CLS suppliers must address is common application programming interfaces (APIs). The US Department of Energy (DOE) realizes that this is a major hurdle to overcome to achieve some of the desired energy benefits of CLS. SSL is more efficient for saving on energy. However, SSL in the form of multiple CLSs that connect to IoT will empower cities of tomorrow to be even more efficient. This increased efficiency will result from CLS coupling together SSL and IoT within a smart grid, allowing a coordination among offices, buildings, homes, retailers, street lights, and similar so that they all work as an optimized, whole system instead of individually. The data that smart sensors obtain combined with data analytics would work to make adjustments that save money for each location within the unified system, which would not be possible if the location was left unconnected from the whole. The DOE suggests making APIs readily available for users while the lighting industry looks at adopting common approaches to security that would seek to minimize system integration issues for the industry.
LED light sources have become an avenue where lighting can move from analog to digital to make life better and easier—through the benefits of an information technology connection to the IoT. Li-Fi offers the potential for CLSs to both provide light and transfer data. With these capabilities, lighting systems could offer an alternative to the ever-shrinking Wi-Fi spectrum to make lighting the hub in smart infrastructure. Connected lighting innovation promises a future that is even brighter than the world we live in today. But as with many future innovations, seeing is believing.
— Paul Golata, Mouser Electronics
Paul Golata joined Mouser Electronics in 2011. As a Senior Technical Content Specialist, Mr. Golata is accountable for contributing to the success in driving the strategic leadership, tactical execution, and overall product line and marketing direction for advanced technology related products. Mr. Golata provides design engineers with the newest and latest information delivered through the creation of unique and valuable technical content that facilitates and enhances Mouser Electronics as the preferred distributor of choice.