In a dusty supply closet at 1 Times Square, a computer terminal hooked up to hordes of ethernet servers, RAID arrays and monitors humbly runs the largest LED sign in the world. The sign, a 3-sided, 17,000-square-foot Goliath, debuted last night at the opening of a Walgreens in New York City. Today, I got to see what makes it tick.
Each side of the sign, designed by D3 LED, requires a 48-drive RAID pumping data at a rate of 3.2GB/second to a custom-built PC. From there, the data is fed through graphics cards to multiple DVI pipes, which lead to six DVI pixel splitters (known as a Spyders). The splitters take video data of a specific resolution and upscale it to the size needed for the display. Once the data is crunched and formatted for the sign, it's sent out via 4Gbps ethernet to one of more than 12,000 display modules that make up the ginormous billboard.
Each module is a mini-computer, complete with MAC address, redundant 4-gigabit ethernet ports, power supply and a fan. Each panel can report all kinds of vital statistics, including its temperature. If there's a problem, the panel reports itself to the main computer for easy troubleshooting. (Like a good communist, it can report problems with its neighbours, too.) The majority of the electronics are accessible from inside, so dangerous repair jobs on scaffolding suspended over Times Square are a thing of the past.
The sign's modules are split into three sections, low-, medium- and high-resolution grids based on their distance from the street. (Why waste pixels for objects way high up?) The top, as you probably guessed, has the largest pixels, at 24mm, while the middle has 12mm and the bottom has 10mm.
The animators are faced with a tough challenge when creating content for the signs, as they must keep the different display sizes in mind so the animation appears cohesive throughout the sections. To help out the animators, sign creator D3 LED made a virtual copy of it that is 10,000 pixels high by 4,000 pixels wide, the equivalent of 43 megapixels. (It's 20 times the resolution of HD, too.) They use an Adobe After Effects template to help coordinate placement of the animations on the slash-shaped sign.
As previously reported, a single 30-second spot on the billboard requires a staggering 150GB of data transferred through the system. But before you accuse D3 and Walgreens of hogging all of the power in New York, they attest that they are not. With the Con Ed bill in mind, their design reduced unnecessary copper wiring by over 300,000 feet and increased the voltage for more efficient power. They also set up an auto-dimmer (like you might have on your laptop) that adjusts the luminosity of the LEDs based on the ambient light outside. All of this makes it not necessarily cheap but at least cheaper than you'd think to operate.
The Walgreens sign is a complex, fascinating testament to the sheer power of LED displays. While most people living in New York avoid Times Square exactly because of things like this, tourists will undoubtedly flock to the centre to observe the sign up close, even though it can be seen from as far away as Bryant Park and the Port Authority. For now, it's something that even this semi-jaded NYC resident can appreciate.