Engineers develop LED-based system to help shoppers locate items in retail stores

Monday, 30 January 2012 02:28

News & Events - Engineering News

January 30, 2012

Scientists are developing systems that would use light emitting diode (LED) technology to help guide shoppers toward items on their grocery lists.

Even seasoned shoppers know how difficult and time-consuming it can be to find a particular item in a store stocked with millions of foods, clothes and electronics, among other items. Armed with radio frequency transmitters and overhead LEDs, researchers from Pennsylvania State University and South Korea's Hallym University are working to tackle that problem.

While it may seem somewhat nonsensical that LEDs be used in such research, scientists throughout the world have actually been successfully working to create data networks using the energy efficient light bulbs. LEDs are based on semiconductor technology, and they have a multitude of uses outside of the lighting sector, according to Penn State chemical and electrical engineering chairman Mohsen Kavehrad.

"LED lights are becoming the norm," he noted. "The same lights that brighten a room can also provide locational information."

To locate a desired item in a mall, the system would not have to transmit a significant amount of data, according to Kavehrad. In the researchers' scheme, rather, stores would install LEDs overhead throughout their facilities, assigning each LED a particular location code. Customers could then access a complementary inventory system that would contain an itemized database of all the store's product offerings.

In their work, the research team developed a hybrid LiFi system using a Zigbee multihop wireless network with the LEDs. They chose Zigbee, an engineering application crafted for small, low-power digital radio frequency specifications that require short-range wireless transfer of data, because it requires a low data rate and offers long battery life.

The researchers noted that light obviously cannot travel through walls, prompting their decision to engineer a hybrid system encompassing both light and radio frequency. When a customer selects an item in the team's prototype system, the request travels from the computer across the short radio frequency receivers and transmitters scattered throughout the retail setting.

"The human eye can't see beyond 15 on and offs of a light per second," Kavehrad said. "We can get kilobytes and megabytes of information in very rapid blinking of the LEDs."

The system then identifies the photodiode tag on the desired item from the overhead LED, sending that information through the wireless network back to the computer. The LED-tracking scheme is efficient and functions optimally even when an item is moved because it reads its location from the overhead LED, each of which is equipped with its own location code.

The location-based LED tracking system could be used outside of the retail sector, the researchers noted. Implementing such a setup in an office building, for example, would enable facility operators to ascertain whether someone were in the building. More specifically, it would also be capable of tracking the person's exact location.

Kavehrad affirmed museums and hospitals would also find such systems beneficial. He said that it would help visitors navigate through large buildings by reading the final destination signal from a handheld photodiode device. Indicating lights would light the appropriate path, allowing for a stress-free visit.

The research team presented their findings at the SPIE Photonics West 2012 conference in San Francisco.