Lighting up the night
Light pollution from electronic signs has negative health effects on people and
wildlife (See articles in this issue), and many towns and states have ordinances regulating the amount of light that can be displayed at night. While
Antes said “the rule of thumb in Times Square is to produce spectaculars on an
awe-inspiring scale,” he indicated that, in some communities, sign and billboard
companies do have to contend with restrictions as to light intensity and content motion on signs. The beauty of LED technology is the unlimited flexibility over visual
content that is displayed and the ability to change it instantly. Content is fully controlled by the computer that runs the display. “You can easily ramp up or tone down
the intensity, color and motion of the content, Antes said. “It’s all configured on a
case-by-case basis and can be designed with consideration of respective community
standards.”
anne.fischer@laurin.com
and making them take notice,” commented
Randy Antes, director of digital projects in
New York City for South Dakota-based
Daktronics. The company has designed
and manufactured many of the large displays in Times Square. He’s found LED
displays to be more energy-efficient than
the old incandescent bulbs, once the standard lighting element in Times Square displays, as well as more dynamic due to
brightness and color clarity.
The famous Coca-Cola sign, a Times
Square landmark since 1920, is a good example. Measuring 44 ft wide by 65 ft tall,
it was converted to LEDs in 2004. According to Antes, what appears to be a
sign is really a sophisticated video screen
run by two control systems that include
four processors and six servers, which can
store up to 120 hours of content. Data and
graphics are sent over a T1 line at 60 fps.
The display has 2,646,336 LEDs in 4000
modules of various sizes.
The transition to LEDs has not been
without its challenges, however. As with
other LED applications, power management
and ventilation/cooling techniques have
been employed to dissipate the heat. One of
the big green changes here is controlling
airflow through the sign rather than relying
on massive air conditioning units.
anne.fischer@laurin.com
Going solar?
Obillboard would be a great spot
for a solar collector – and in
ne would think that a giant
theory, it is. Regular billboards that
don’t have electronic displays can be
power generators, as demonstrated in
San Francisco by the solar billboard
sponsored by Pacific Gas & Electric,
which displayed the message, “This is
not a billboard, it’s a power plant.” The
20 solar panels installed on the billboard provided 3. 4 kW of power in full
sun, ran the LED lights above the display and fed unused power back to the
grid. Times Square now has a solar-and wind-powered sign, but again, it’s
not an electronic sign. But providing
solar power to huge digital signage is
not yet practical for most applications.
According to Pamela Thompson of
Sugarman Consulting, to fully power a
14- by 48-ft digital billboard, you’d
need almost an acre of solar panels.
Sugarman Consulting has done some
projects with solar, but, as Thompson
pointed out, unless the advertiser has
very deep pockets and a whole lot of
vacant land (for the solar collectors),
solar just isn’t a viable option for large,
power-hungry digital signage.
Thompson adds, “We are developing
secondary solar power systems that
augment the primary power source.
Keeping the LED display cool is critical, often requiring a forced-air ventilation system or, in some cases, air conditioning. Using just a few solar panels
mounted on the back of the sign, we
can power a supplementary ventilation
system that kicks in during the hottest
and brightest part of the day.”
anne.fischer@laurin.com
