Future proofing lighting systems with Bluetooth

By Alessandro Mastellari   |   May 9, 2018

The lighting industry is not short of options for digital connectivity. Numerous standards have fought for supremacy, from DALI and DMX to EnOcean and 6LowPAN. Each one has strengths and weaknesses. The popularity of each has waxed and waned as integrators discover ways to implement features that digital messaging brings to lighting control. But each time integrators switch to a different protocol to access its features a resulting change in the infrastructure is required. At the same time, stocks of older subsystems need to be maintained to support older installed systems. What the lighting industry needs is a connectivity standard that itself adapts to change. With Bluetooth 5, that standard has arrived.

Originally conceived as a personal area network (PAN) designed around the mobile phone, Bluetooth has evolved and grown in scope – taking it way beyond PANs to building-sized networks. The changes have adapted a robust wireless protocol into one that fits into many vertical markets. A number of the changes made for version 5 are particularly applicable to lighting. They make Bluetooth not just the protocol to future proof your lighting installations but also to unlock access to future value-added services.

A major addition made to Bluetooth 5 was support for mesh networking. Thanks to the mass-market adoption of Bluetooth that has seen billions of compatible transceiver ICs and SoCs shipped, mesh networking provides lighting-centric features at the cost levels the industry requires.

A key design issue that has faced integrators using digital lighting-control protocols such as DALI or DMX is one of topology. Star or bus connection is often enforced by the protocol. The layout of the wiring and routing to the lighting control box is determined during installation and remains fixed until the entire system is replaced. Although software in the lighting control can make it possible to change configurations as room partitions are moved around, there are often limitations.

Mesh networking has the advantage of easy adaptability. Whenever a new lighting node is added to the network it detects its nearest neighbours and quickly forms into the most efficient topology available at the time. If a lighting node fails, others quickly find their messages are not being received and so form new connections using different neighbours. Mesh networking also has the advantage of scale. Each lighting node added to the edge of a network expands the size of that network. Potentially, a single controller attached to the building-control system can send illumination commands to all the luminaires in the entire building. The range of a point-to-point Bluetooth connection can vary from a few metres to several hundred metres, depending on the type of module and environmental conditions. But luminaires are almost always more closely spaced than this so the single-hop range is practically never an issue.

Once in the mesh, luminaires will be divided into virtual groups that are controlled by software commands. Forming a cluster of lights into a room or defined area is as simple as adding them to a group and sending dimming commands to that group. The mesh will take care of relaying the command packets to the relevant luminaires. And it’s a system that adapts to new requirements readily.

Let’s say you start off with an installation that uses software to define rooms and lighting areas and connects each to physical Bluetooth-connected switches on the walls. Later, the building owner may want to employ available-light harvesting. Adding Bluetooth-enabled sensors to the network makes it possible to report ambient-light measurements in specific locations to nearby luminaires. A traditional system might simply dim all of the lights to a setting based on this value. Thanks to the local intelligence in each Bluetooth node, individual luminaires can use knowledge of the difference between their location and the sensor’s to adapt the lighting level to one that is more comfortable for users underneath.

There is no need to stop there. Lighting can adapt to the tasks being performed underneath and even help people track assets. Beacon technology is another recent addition to the list of Bluetooth capabilities. This lets objects announce their presence and status to nearby Bluetooth receivers. The lighting mesh provides a way to map where those objects are and even announce their presence by brightening when the user looking for that asset approaches. Bluetooth has the data-transmission capacity and performance to deliver additional services – which may go way beyond just lighting control – as they are defined and rolled out.

If upgrades are needed to support new services, it is easy to replace luminaires gradually without changing the underlying network technology. Integrators can be sure of finding compatible modules.

In digital control systems, security is an ongoing issue but Bluetooth has that aspect covered as well. The protocol offers dual-layer security: operating at the network layer and the application layer so that messages can be secured with two independent keys. This ensures that messages can be keyed to individual groups and also that individual devices that may have been compromised cannot change commands destined for another node.

The result is, finally, a network technology that makes sense for lighting integrators working across a wide range of scenarios now and into the future. If you're interested in Bluetooth mesh and looking to take the modular approach, watch our webinar with Panasonic, where we will explore their wireless connectivity modules, development environment and tools. Alternatively, click the Ask an Expert button get in touch with one of our technical specialists in your local language.

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About Author

Alessandro Mastellari

Alessandro has over 20 years experience in the electronics industry, spanning product management and...

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