The continuing development of lighting controllers
According to a report by Zion Market Research, the smart office market is expected to be valued at $49.7 billion by 2024. This growth reflects a wider move for greater technology in office spaces, often in the use of lighting controllers to improve building energy efficiency and reduce costs. Although these technologies are ubiquitous today, they were truly innovative 20 years ago when embedded computing specialists such as Recab UK were first approached to develop novel lighting control systems.
A review of occupancy-based lighting control, published in 2017 in Building and Environment, stated that lighting accounts for approximately 45 per cent of an office space’s annual electrical consumption. Even more, the same review stated that this consumption could be reduced by as much as 60 per cent by introducing occupant-dependant lighting control systems.
When we consider that a 2011 review on energy saving potential in office buildings estimated the annual European office energy intensity to be approximately 306 kWh/m2, it becomes clear why more offices are adopting lighting controls. Although there are several ways that offices can become more energy efficient, the option to link lighting usage with core work hours and room occupancy undoubtedly offers significant savings.
This has become more common in recent years, but it’s an area of embedded technology that Recab UK has extensive history in. Some years ago, Recab UK was approached by a customer that wanted to develop a bespoke controller that would allow office lighting to automatically turn off at certain times of day. This came as a result of the customer observing that, in many cases, staff would leave lighting on — at the expense of the company — after leaving the office. If staff were still on premises, they could turn the lights back on as necessary, and the controller would automatically turn them off after a defined period of time.
In such a system, size is a key consideration. The customer also had specific requirements for the device. It had to fit into a compact footprint, boast long-term availability and feature custom connectors and circuitry. Recab UK had to not only meet these specific requirements and space constraints, but also to do so in an economical way.
Specifying components
“Due to the relatively low numbers, a full custom motherboard by one of our vendors wasn’t economical,” explains Mark Jeffrey, technical director of Recab UK. “A computer on module (COM) design was chosen using an ETX module. The benefit of a COM design is that you tailor a baseboard around the customer’s requirements and use the core input/output (I/O) of the COM module.
“When that COM module reaches end of life due to component obsolescence, all that you have to do at the mechanical level is replace the ETX module for a newer design. Only some small software changes would typically need to be done to the customer’s image.”
The first step of the project was for Recab to determine the right COM module for the application. In most cases, this will involve a trade-off between processing power and cooling capabilities. Because most lighting controllers will be introduced to buildings to improve energy efficiency, cooling was particularly important. Faster processors generate more heat and, in an application where the processor may be situated at the rear of a device, a complex cooling solution or an active cooling solution might be the best option.
Once the exact COM module has been determined, Recab focusses on efficiency by selecting the most efficient DC to DC converters on the system board. This uses less power from supply and reduces heat in the device itself.
All standard ETX interfaces, except for low-voltage differential signalling (LVDS), were brought out to standard PC type connectors or internal headers. In addition to the two standard RS-232 serial ports that feature on the ETX, Recab included two additional COM ports via the carrier board. These could be configured as either RS-232, RS-422 or RS-485. Storage was provided via dual IDE headers and an externally accessible compact flash socket.
This solution, with the design expertise of Recab UK, was an ideal fit for the lighting control requirements of the customer. The use of the ETX module at the heart of the system made future upgrades easy as component obsolescence occurred and as newer COM standards came to market.
A changing market
Today, the process of developing a lighting controller is substantially different as embedded technology has changed considerably. If the same project was undertaken today, there are some immediate changes to the footprint that could be achieved by using a SMARC board rather than ETX. A SMARC specification board for an application such as lighting control would measure 82 mm x 50 mm — considerably smaller than the 95 mm x 114 mm footprint of ETX.
Similarly, the memory capabilities of the controller could be enhanced by swapping out the use of compact flash memory for an M.2 solid-state drive. This would allow much greater memory capabilities for the system, in turn supporting more complex controls.
“The lighting control market today has advanced considerably, with many controls today being far smaller — the way that all electronics tend to go,” continued Jeffrey. “In many cases, there are highly compact controllers that can prove more economical than a COM design today, but with the same fundamental design principles.
“However, the modularity of COM and the wide range of compatible components available mean that it is an ideal platform to continue to innovate in smart building technology. With the right design expertise, there are countless opportunities for COM to underpin increasingly sophisticated smart office technologies, which can futureproof offices for years ahead,” Jeffrey concluded.
Smart building and office environmental control technologies may be evolving and becoming more economical for businesses, but the innovation that preceded this ubiquity cannot be understated. With the capabilities of embedded computing also continuing to develop, it is the innovation and design expertise of specialists like Recab UK that can continue to shape the road ahead for embedded technology.
This article first appeared in the March 2021 edition of Industrial News.
