Digital Ceiling Makes Smart Buildings Even Smarter
Tom Lombardo posted on February 22, 2016 |

If you look up "intelligent" in the thesaurus, "bright" is one of the synonyms you'll find. When  Cisco decided to create an intelligent building network, allowing many IoT (Internet of Things) devices to communicate with each other, a light bulb went on over some engineer's head: "Let's use the lighting system as our network!" Thus, Cisco's Digital Ceiling was conceived. When fully implemented, the Digital Ceiling will offer building occupants a combination of information, efficiency, convenience, security, and comfort.


Efficient Use of Energy and Wiring

The Power over Ethernet (PoE) standard, officially known as IEEE 802.3bt, allows both power and data to be transferred over the same wires. When Cisco engineers looked for an IoT device that's common to all rooms, lighting was the obvious choice, so they decided that DC powered LED fixtures would be the heart of the control system.


LED light fixtures are more efficient than incandescent or fluorescent lights, but their Achilles' heel appears to be the AC-to-DC driver. LEDs are inherently DC devices that need a driver to convert AC from the wall into DC. The driver circuit is a source of power loss and premature failure; running LEDs directly on DC improves both efficiency and reliability. Since lighting is controlled by building management systems and it can run on relatively low power DC, PoE is an ideal power source.


Imagine a corporate meeting room or a college classroom that's only used during certain time slots. Even if someone remembers to turn off the lights after the meeting or class, the HVAC will continue heating or cooling the room as if someone were in there. With the Digital Ceiling, sensors can be embedded into light fixtures, providing the network with information such as room occupancy, temperature, and ambient light levels. Using that data, the building automation system can set up the room's ambiance according to present conditions and requirements, maintaining comfortable levels of light, temperature, and even air circulation, without sacrificing efficiency. Coupled with room scheduling software, the system will turn off lights and reduce heating/cooling/ventilation when the room is unoccupied, and automatically bring them back to life when needed.



Integration of System Controls

Cisco's goal is to integrate building management systems, IoT control, information, security, and sustainability endeavors into one cohesive unit. To accomplish that, the company is developing a line of network switches that will reside in ceilings near the light fixtures.


If you've connected your laptop or tablet to a WiFi network, you know it takes a few seconds to obtain an IP address from the router. That process is even longer when the router has just been rebooted (e.g. when power has just been restored after an outage) since the router needs to get its own Internet connection established before dishing out local IPs. To eliminate these delays, the Digital Ceiling has a quick recovery mode that remembers previous settings and uses them as the default while the whole system reboots. In short, your lights will come on immediately after power is restored, even though the control system is still getting its act together.



Sensor Markup Language: HTML for Building Controls

To facilitate communication among devices, Cisco is using the open standard Sensor Markup Language (SenML), similar to the web's HTML. Just as HTML provides a universal language for web page developers, independent of server or client platform,  SenML allows anyone to create apps and devices that work in the Digital Ceiling. I can picture renewable energy sources and behind-the-meter energy storage being incorporated into the Digital Ceiling network, allowing facility managers to not only control a building's energy consumption, but also regulate and manage its peak demand and time-of-use charges. Future services could also include fleet EV management and vehicle-to-grid operations.


Images courtesy of Cisco



All told, I see massive opportunity for hardware and software developers to get in on the action. The World Wide Web and HTML were introduced to the public in 1991 and the Internet explosion soon followed. The first time I sat down in front of a browser - Lynx, a text-based browser running on a Unix machine - I never imagined that in just over a decade, any person, regardless of technical aptitude or lack thereof, could become not only a consumer, but a producer of web content. It's exciting to think of what smart buildings - and by extension, smart communities - will look like in another ten years. Although the word "ceiling" implies a top boundary, I think the Digital Ceiling's upper limit is pretty high.


If you'd like to see a 20-minute presentation about the Digital Ceiling, here's John Parello, Senior Technical Leader at Cisco, presenting at Tech Field Day on February 15, 2016. Beware - the talk includes a hefty serving of acronym soup!






Cisco Digital Ceiling Design Discussion with John Parello from Stephen Foskett on Vimeo.


What other applications do you see for the Digital Ceiling? Please comment below.



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