While many screen-media systems are driven by conventional PCs, single-board computers can do the job just as well - and now many of them have specific digital-signage features built in. Andy Stevens of hardware distributor Trident suggests that it's time to go industrial...

LCD technology has brought about a revolution, offering huge benefits over CRT, plasma and traditional signage products. With consistent year-on-year price erosion of panels and increasing availability, reliability, flexibility and technological advancement, it seems everybody wants to make use of this form of dynamic communication. But although much has been said about the evolution of the display, the computer hardware required to drive the panel is often overlooked. In the past, digital signage usually consisted of a two-box solution - the screen and then a computer, networked into a room onsite or hidden in the roof above the display, for example.

The computers used were consumer-style ‘cream boxes', very similar to the ones found in offices and homes worldwide. The idea of using embedded computing solutions such as single-board computers (SBCs) to drive digital signage was originally disregarded for a number of reasons. The cost of SBCs, a relatively unproven and unheard-of technology in the digital-signage market, was much greater than consumer-style PCs. Retailers and businesses alike want a fast return on investment on their displays and it is very difficult to truly measure the return on this type of investment.

Graphical performance was another issue; digital signage is concerned with running rich multimedia content, driving pixels at a native resolution which typically for widescreen (WXGA) is 1360 x 768 pixels. In the past, SBCs did not support this and were more tailored toward industrial applications where graphical performance is less of a prerequisite when choosing a board.

Recently, however, SBC manufacturers have started to recognise the growth of the digital-signage market. They are moving away from specialising in industrial-specified products and are designing and manufacturing boards with high graphical performance in mind. A good example of this change is high-definition compatibility and the inclusion of dual independent display capabilities, where two separate images can be run off the same board.

High graphical performance

This is ideal for kiosk and over-the-counter applications where the customer may be looking at one screen and the employee, such as a fast-food attendant, may be looking at a different screen. An example of the benefit of this is the opportunity for the sales representative to be prompted with questions to upsell or promote other products. Industrial computing is renowned for long-term reliability, with SBC manufacturers offering support for five years or more. This is a far cry from consumer-style computers, which have a short product life and require frequent upgrades or replacing.

The cost of routine maintenance and upgrading a digital-signage solution is minimised through this industrial reliability. The majority of SBCs are now passively cooled (fanless), which not only gives them a longer MTBF (mean time between failures) because of less moving parts but also makes their operation near-silent.

This is another benefit for a location with a multitude of displays, where the constant low-level humming can be distracting, such as a museum.

"Having said this, some customers are still concerned about pricing, so we tend to offer them a number of choices, including a full-blown signage system, as well as budget-priced system," he said. "And if the customer elects to go for the budget-priced system, we always point out the limitations against a full-blown system, but at the end of the day we do recognise that customers have budgets too," he added. The downward price trend in screens and allied hardware, said Young, has not resulted in any reliability issues coming to the fore.

"You've got to stick with established brands, of course. Our observations suggest that LCDs will have an average lifespan of 12 years or so, but the fact that none of our LCD deployments is over three years old means that we haven't encountered any problems," he said.

Unlike Remote Media, and in common with most of the digital-signage industry, Young's company prices up its systems for clients on the basis of an upfront capital cost followed by ongoing maintenance. But do the customers ever look for a monthly rental option? "Not that I've encountered. You can always include a leasing arrangement for a customer if upfront costs are a problem, but my experience is that customers tend to know what they are looking for and are happy to pay the price of a signage system once they realise the benefits," he said, adding that it is always better to buy a system than rent one. Young believes that site visits can be minimised - and maintenance costs kept under control - by always using branded hardware.

"LCDs are definitely getting more reliable these days. Two-year guarantees are the norm and, by using remote access, if a screen does hit problems, you can always remotely blank it until the engineer reaches the site," he said. And screen burn-in issues can be avoided by sticking with established brands, according to Young, even if they are not the cheapest. "Most of the latest LCD screens from the major vendors have automatic pixel-shifting, so screen burn problems can be avoided," he said, adding that unnecessary screen swap-outs and site visits are then kept to a minimum.

Screen rotation

There are many other features manufacturers are developing from industrial products. A watchdog timer allows fully programmable detection and logging of specific errors as well as an automatic reboot. How many times have you walked into an airport, looked at the departure screens and found that two or three are switched off or with no content running? This programmability allows only the detection of errors that the user sets before logging and rebooting of the display.

Other digital-signage-specific features include hardware screen rotation, which enables large-screen displays such as NEC's LCD4010 to be viewed in portrait mode. MPEG-2 acceleration allows the playing of DVDs with minimal CPU overload, and widescreen support further enhances the viewing experience.

Another advantage of SBCs is that they minimise the impact of faults. Many digital-signage networks run off different computers and are sometimes daisy-chained to reduce costs. But with this arrangement, a computer error may lead to all the screens switching off and a system reboot. With an independent unit, each screen is run by its own SBC, so in the case of a technical problem it is obvious which screen is faulty and repair or replacement becomes a relatively simple task.

The option of cabled and wireless networking gives these one-box solutions added flexibility. The future of SBCs in digital signage is without doubt the move towards a true one-box solution.

The evolution to smaller form factors will enable the SBC to actually sit inside the display and opens up a host of new opportunities in smaller-screen digital signage such as shelf-edge advertising. Boards are now starting to support widescreen formats in digital and there will soon be little requirement for analogue-to-digital cards.

The days of ‘cream box' PCs sitting in the ceiling cavity are coming to an end. System integrators are becoming more and more aware of the technology behind digital signage - and not just the large LCD screens. Consumer-style features, high-quality components and industrial reliability are now prerequisites for embedded computing in this arena.

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