Using LEDs to convey data in the optical domain is a popular concept. With fast on-off switching times, led street light wholesale can be modulated in a manner that conveys data to some type of sensor while humans would not perceive anything more than uniform white light . Therefore, LED-based lighting could serve the dual purpose of providing lighting and communications.
Some researchers and companies are pursuing the use of LED-based VLC as a way to augment Wi-Fi for high-speed data connections within a small area with a clear line-of-sight between a light fixture and a device such as a notebook PC. That technology is not ready for commercialization and we will not address it further in this article. But VLC could more easily be applied in lower-data-rate applications such as in location services. Indeed, modulated LED light captured by a mobile device camera is a technology that is very near ready for deployment. The operation of GE's system is depicted in Fig. 1.
Retailers are interested in the technology as a way to increase the size of the sale to any given customer. A mobile device app combined with location data offers a retailer many ways to engage the customer. The retailer could offer a custom sale item to a shopper based on the spot in the store where the customer is browsing. A shopper could use the app to locate items of interest. And retailers could target shoppers with specials based on prior shopping data.
During LFI, GE hosted some roundtable press meetings in which several of their LED lighting customers participated. One of those discussions included Ralph Williams, Walmart senior mechanical, electrical, and plumbing systems engineer. Williams said the retailer is investigating the location technology in its Walmart Innovation Lab. Moreover, he said the company has documented that 40% of its in-store customers actively use a smart device as part of their shopping process. So the data clearly indicate a receptive potential customer base, leaving SSL manufacturers and retailers to iron out the details.
To support Lumicast, Acuity simply has to modulate the light from an LED fixture in a manner that is compatible with the Lumicast platform. Lydecker said in the case of the Breez LED fixture (Fig. 2) from Acuity's Lithonia brand that was demonstrated at LFI , the EldoLED ECOdrive driver used in the fixture has the capability of implementing the modulation. The microcontroller (MCU) -based driver would require a firmware or software addition to support Lumicast but no additional hardware. Acuity could offer Lumicast support as an option across its luminaire line.
Acuity's Lydecker said the primary benefit of BLE would be the ability to connect to a smartphone that is in a customer's pocket or purse. Of course, since any such retail-oriented location application requires the customer to opt in to the services and download an app , the customer would presumably have the device out and available when shopping. Lydecker said Acuity will add BLE support if retailers ask for it, although he also added, "The light fixture may not be the best place for a Bluetooth beacon."
Clearly, you could do a location platform with no VLC. Indeed, Apple is pursuing just such uses with its iBeacon platform for which third parties can build compatible beacons and apps. For now, GE is hedging its bets with support for the Apple platform. Qualcomm also has a similar BLE-based platform that it calls Gimbal.
With the huge players in mobile wireless focused on the retail application, it's again worth asking, why use LED lighting as part of the equation? Dedicated BLE iBeacons do cost money. Some are projecting beacon cost under $ 10, although today the reality is higher. Startup Estimote sells a developer's kit with three beacons for $ 100. The beacons also generally run from batteries requiring maintenance cycles.
Still, the biggest advantage for VLC may come down to accuracy. Qualcomm asserts that Lumicast, enabled by software on the mobile device and in the cloud, can determine the location of a mobile device to within 10 cm in three dimensions. Moreover, the led street lighting fixture can detect the orientation of the device so a retailer could discern on which side of the shopping aisle the customer is focused. BLE beacons would not be deployed granularly enough to enable near that level of accuracy.
Still, it's entirely possible that a mix of BLE and VLC will be used in retail location services. Moreover, a company such as Qualcomm with both VLC and BLE platforms could enable such an integrated approach. Or the actual desires of shoppers could make the level of detail possible with VLC overkill.
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