by Paul Golata, Mouser Electronics
Gone are the days when lights were standalone devices whose sole purpose was to illuminate a particular area. The rise of connectivity and data-dependency in our lives means the role of luminaires is changing. Connected lighting systems (CLSs), using light-emitting diode (LED) technology and Internet of Things (IoT) connectivity, now enable design engineers both to provide illumination and transfer data. This opens up fresh opportunities to save energy and unleash new benefits and services for individuals, businesses, and communities.
Underpinning ever-more CLSs is LiFi, an emerging optical wireless technology, short for ‘light fidelity.’ Launched back in 2011, it puts lighting at the core of smart infrastructure. Using IEEE 802.11 protocols, LiFi is gaining momentum as an alternative to WiFi. Below, we’ll explore CLSs, LiFi, and the IoT in more depth, and look further at which supporting technologies will enable CLSs to reach their full potential.
How the IoT is revolutionizing lighting
The impact of the IoT on the world has already been immense. In the lighting space, by blending modern optical sensors with wireless connectivity, engineers can now concentrate both on collecting data and transferring it into the digital domain to drive analysis and informed action. Let’s look briefly at each of these key areas.
Modern optical sensors
There are sensors all around us, recording data on everything from temperature and humidity to levels of volatile organic compounds (VOCs) and vibrations. These sensors convert analog signals into digital data that can be read, analyzed, manipulated, and acted upon by a range of systems.
The sensors we’re interested in are optical sensors, which turn light into electrical signals. This means systems can sense things such as whether lights are switched on or overall light intensity.
Wireless connectivity
Wi-Fi enables devices to connect to a nearby wireless network, using electromagnetic radiation in the radio frequency (RF) spectral range, which is between 20kHz–300GHz. Wi-Fi operates at five main frequency ranges: 2.4GHz, 3.6GHz, 4.9GHz, 5GHz, and 5.9GHz. The majority of consumer electronics use the 2.4 GHz and/or 5 GHz options. While incredibly widespread, Wi-Fi isn’t without its problems, including its vulnerability to hacking and the fact that its spectrum is getting close to capacity. This is where LiFi comes in, which we’ll explore shortly.
Data
Storing data digitally makes it available for all sorts of purposes, including curation, application, and extension through the use of Big Data Analytics (BDA) and artificial intelligence (AI). The key design goal of CLSs is to make lighting systems part of this broader technological framework, with the aspiration of creating more intelligent, end-to-end systems.
LiFi: Communicating using light
CLSs are built around solid-state lighting (SSL), which uses LEDs rather than filaments, gas or plasma. LEDs are robust, compact, energy-efficient, and generally long-lasting. They also give designers flexibility when it comes to controlling colors and output lumens, as well as the ability to modulate between on and off. And it’s this latter characteristic that’s critical to LiFi.
Where Wi-Fi delivers data using radio waves, LiFi is what’s called an ‘optical wireless communication’ (OWC) technology, meaning it uses light waves to communicate. These could be in the visible spectrum, or infrared and ultraviolet. LiFi can deliver reliable, high-quality streams of data at speeds that compare well with Wi-Fi—over 30Mbps in some cases.
Using light rather than radio waves to transmit data has a number of benefits. Firstly, the visible LiFi spectrum is almost 10,000 times bigger than its RF equivalent. Second, LiFi is highly hack-resistant, because it uses line-of-sight (LoS) architecture: if someone attempts to intercept the data stream, the data’s circuit path is destroyed, and nothing is conveyed.
As we touched on above, LEDs’ ability to quickly modulate on and off is a key enabler of LiFi, where data gets transmitted via modulation and demodulation schemes. LiFi works by feeding streaming data into an SSL driver, which controls one or more LED lamps, switching them on and off at extremely high speeds, faster than the human eye can see. This strobe of illumination can be picked up by a photoreceptor in a LiFi dongle. This produces an electric current in proportion to the amount of light hitting the sensor. This signal then gets amplified, conditioned, and processed, before being sent wirelessly to another device, such as a computer, tablet, or smartphone.
Creating a coherent ecosystem
For a couple of years now, several LED manufacturers have been focusing on creating truly unified CLS solutions. By this, we mean lighting that can interact with all electro-mechanical systems in one place. Creating a comprehensive solution ensures interoperability, high performance, and reliability. This work has demonstrated the need for support from four key areas to help CLSs reach their full potential: hardware, the IoT, software, and interfaces.
Hardware
The hardware components require both LEDs and suitable drivers to control the current being passed to them. Designers also need to think about the related electro-optical-mechanical functions, to enable them to turn their products into useful luminaires. The hardware might require heatsinks to keep temperatures down, as well as components to control the optics, mount the unit, package it, and integrate it with other devices, using common design codes. Equally important is the need to include intelligent sensors that can turn analog information into digital signals.
With all these components in play, the key challenge for designers is to ensure everything works in harmony.
The IoT
Hardware, of course, is just one part of the equation. CLSs need to be able to connect up with other lighting systems so they can work together. CLS makers need to think about the challenges these integrations pose, notably around data security. How will they protect data against unauthorized attempts to intercept it or take control of the system? This may demand work around authentication, to ensure only those with the right keys have access. Other areas to consider are storage, servers, and analytics.
All of this will help ensure the process of getting data onto and off the CLS is secure and reliable.
Software
Today’s product designers have access to a host of cloud-based services that their colleagues from yesteryear could only have dreamed of. CLS providers who can offer cloud-based technology services to complement their hardware will be in an advantageous position because customers will have quicker and easier access to the full benefits of the CLS they’ve purchased.
Future interoperability is also critical. Standards-based solutions, which enable different manufacturers’ products to work together seamlessly today and in the future, are likely to help drive faster growth. Conversely, products that don’t work well with others may find themselves at a disadvantage, because of the requirement to work across domains and boundaries.
Interfaces
The final area for CLS makers to consider is common application programming interfaces (APIs). This has been recognized by the United States Department of Energy as a significant challenge that must be overcome if we’re to realize the full energy-related benefits of CLSs.
Solid-state lighting on its own is already highly energy-efficient. But the really significant savings can come when you connect up multiple CLSs across larger areas. This offers the potential to make tomorrow’s cities more efficient by creating a smart lighting grid that spans homes, shops, workplaces, and street lighting. This will enable larger areas to work as a unified whole, rather than as many individual elements. With sensors collecting data and feeding it into analytics engines, the lighting systems will be able to adjust luminaires in real time to save money and energy. The US Department of Energy has recommended that while the lighting industry looks to adopt standardized security approaches that will minimize integration challenges across the sector, APIs should be made available to users.
Conclusion
LED-based lights are enabling lighting to go digital, with luminaires connected together as part of the IoT. As a result, modern CLSs offer the potential to genuinely improve our lives, finances, and the world we live in.
The LiFi protocol enables CLSs to provide illumination and send data back and forth. These capabilities mean LiFi-based lighting systems could provide a real alternative to using the ever-more-crowded Wi-Fi spectrum as the core of smart infrastructure.
And with innovation around connected lighting proceeding at pace, we expect to see an even brighter future than the world we live in today.
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