The impact of wireless standards on home and professional lighting
Home and professional lighting systems have traditionally been two different worlds. Homes were wired using simple cable and switching, whereas larger buildings might have more sophisticated electronic controls, using customer or open protocols such as DALI. In both cases, they tended to be based on wired systems, either with simple switched mains power routed to lights, or using controller units with separate power and control cabling.
DALI & DALI+ protocols
The DALI protocol mentioned above stands for Digital Addressable Lighting Interface, created as an open standard by a consortium of lighting appliance manufacturers. The standard was originally based on a wired protocol, and defined both physical transport characteristics (bitrate, voltage levels, etc) and message formats. Messages encode lighting commands such as switch on or off one or more appliances and set levels of output.
More recently, the DALI protocol has been enhanced to support wireless connectivity via DALI+. This effectively separates the application layer (message specifications like switch on, dim, etc), and the physical communication layer. DALI+ supports IP based networks including wireless networks, and in particular, Thread and WiFi as well as wired Ethernet. Other protocols such as Bluetooth may be supported later.
This architecture allows pure wireless networks to be based on the DALI+ protocol, but also enables the possibility of bridges between a traditional wired DALI network and a wireless one.
Although DALI could have been used for home smart lighting, in practice, it was mainly used in professional buildings – offices, factories or warehouses. This kind of solution was rarely found in domestic buildings, due to cost and the lack of appropriate technical skills of home builders. So simple wired power switching is still used in most situations. However, wireless networks have become pervasive in homes, initially for connecting computers, and more recently for TVs, games consoles and other domestic appliances as well as smartphones, using a mix of Bluetooth and WiFi
Matter protocol
The emergence of smart speakers as control units has led to the development of industry standards, and out of this the Matter protocol has emerged as a multivendor standard for the smart home. Whilst not specifically targeted at lighting, it can be included in the scope of a home network, either directly via a Matter controlled lighting unit, or indirectly via Matter controlled smart plugs.
Matter is an application layer protocol and, like DALI+, runs on top of WiFi and Thread. Apple, Google and Amazon, alongside various device and appliance manufacturers are promoting Matter. The aim is for a Matter compatible device from one vendor to be commissioned on the network, and then controlled by another vendor’s device.
Bluetooth Mesh
A different alternative is Bluetooth Mesh (BT Mesh) which uses the Bluetooth radio technology to create a network that can be used for lighting. Whilst not restricted to this application, it is clearly targeted at lighting type applications. The main difference between BT Mesh and DALI+ or Matter is that BT Mesh is designed to not require any central controller but allows any device to communicate with any other.
It has the benefit of the relatively low cost and low power consumption of Bluetooth devices. However, there are question marks about its scalability and efficiency – meaning that a large-scale installation might not function well. It also is limited in bandwidth, which may not be an issue for a smaller network of simple devices but could be a limitation in a more complex scenario. Whilst it may suit certain niches, there is an argument that it is trying to push Bluetooth technology into a domain it wasn’t really designed to handle.
It is notable that there are number of proprietary or semi-open Mesh type protocols running over Bluetooth that have gained some traction, such as Wirepas (a general use mesh protocol), or Casambi, a lighting focussed offering. These are vendor controlled, but offered to the market under terms designed to attract partners. The existence of such offerings is perhaps indicative of limitations of standard Bluetooth Mesh.
Returning to DALI+ and Thread - given that we have two wireless networks, both based on Thread/IP networks - two questions arise. Are these in competition, and will there be a “winner”? In the short term, probably not. The two standards are being driven by quite objectives, and by largely different industry players.
DALI is driven by a diverse group of manufactures of lighting appliances and controllers, with the objective of facilitating the adoption of sophisticated professional solutions. Priorities are easy control of lighting systems, efficiency (via features like presence detection) and safety (where special requirements exist for larger buildings). It has a relatively long history of being used as a robust professional solution.
By contrast Matter is being promoted by consumer electronics brands as a way of linking diverse appliances into a unified system. As such, it is more an additional layer linking devices that were previously not connected to anything. Taking a more cynical approach, one might also argue it was a means for the likes of Google, Amazon or Apple to embed themselves in the heart of people’s homes. It is also worth noting that the smart speakers/controllers typically have integrated cloud connectivity, which offers both advantages in functionality and risks in terms of security.
Nevertheless, there may be some overlap where the best approach is not obvious. Smaller offices might be more economically and efficiently managed via a Matter network. There is a potential cost advantage in a consumer-based technology which can achieve extremely large volumes.
Wireless lighting – the future
What is clear is that the many advantages of wireless technology will mean it becomes increasingly prevalent in lighting and building systems. It is easier to install, easier to manage and update and cheaper to operate a wireless system than a traditional fixed wire one. The building industry has not traditionally been a fast adopter of technology but nevertheless the pressure to do so will become ever stronger. The goal for manufacturers of wireless lighting products must be to make the transition as easy as possible.
Nick Wood
Sales and Marketing Director
Insight SIP
This article was first published in All About Circuits
