In today's concrete jungle, pavement takes up a lot of space, so we might as well cram some smarts in there. Previously we've seen ground coverings that light up, absorb solar energy, generate electricity from the footsteps of pedestrians, and even emit Wi-Fi signals. Now NASA is combining a little of all of those in a high-tech new path due to greet visitors to the Kennedy Space Center.

The US$2 million installation is made up of about 1,000 tiles spread across 40,000 square feet (3,700 sq m). These tiles form mosaic images of Earth, Mars, the Moon and the International Space Station, but it's what's inside that counts.

Each tile contains circuit boards, six small solar panels, a battery, LEDs, a Bluetooth and a Wi-Fi transmitter, micro controllers and a piezoelectric element. All of this is encased in cavities in thin, high-performance concrete and topped off with a strong glass tile. Piezoelectric systems generate energy from mechanical stress, and in this case that means footsteps.

"No one has made anything like this — an outdoor tile system using a piezoelectric element to trigger customized and off-the-shelf electronics and coupling them for human interactions," says Ilan Stern, senior research scientist at Georgia Tech, which is collaborating with NASA on the project. "When you step on the load-bearing glass tile, it compresses the piezoelectric element, creating an electrical charge that lights up the cavity's 125 LEDs."

Along with lighting up in a variety of colors, the tiles can also beam a wireless signal to the phones of passersby to deliver nuggets of wisdom on NASA's space missions, the mechanics of piezoelectric technology, and other things.

"The piezoelectric element also powers a Wi-Fi or Bluetooth signal to visitors' smartphones, which can play audio, providing information about their geolocation and for potential wayfinding," says Stern. "The audio provides information such as how much energy is being generated throughout the park during the day."

The system is completely self-powered, but not just by the piezo elements: The solar arrays are constantly absorbing energy from the Sun as well, and it's all stored in a rechargeable lithium battery for nighttime use.

Ultimately, the aim of the project is to showcase "smart city" applications of the technology. Installations like these could be used to power local devices like street lights, guide visitors to points of interest, or collect real-time information about traffic and road surface conditions.

"We need a more flexible use of the electric grid," says Stern. "Our goal is to develop more self-powered, self-generating systems with added storage that will give us more choices in energy usage and minimize waste. As much as possible, we should convert wasted mechanical energy—human and vehicle movement — into usable energy generation and storage."

Source: Georgia Tech

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