Consumer-grade LED light bulbs can be enhanced with basic light-receiving electronics to enable the sensing of incoming signals from other light-emitting devices. The enhanced light bulbs are powerful enough to establish a communication link across several meters between light bulbs and LED-only systems that can be integrated into many devices. The indoor visible light communication (VLC) system, called EnLighting, enables distributed and fully connected LED light bulbs to communicate through free space optics and may be a way to both light a room and provide a communications link. Conceptual illustration of EnLighting, an indoor visible light communications system. Courtesy of Disney Research. Researchers at Disney Research and ETH Zurich designed and implemented the system, demonstrating that it is a viable way to interconnect devices within a room. "We used commercially available, off-the-shelf LED light bulbs as our starting point," said researcher Stefan Schmid. "They are readily available at low cost and can be used in any lamp with standard sockets. This leads to an easy-to-setup and flexible testbed that can be readily duplicated." The researchers added a system-on-a-chip (SoC) running an embedded version of Linux to each bulb, as well as photodiodes to enable sensing of incoming signals and an additional power supply for the added electronics. The individual LEDs were able to alternate between sending modulated light signals and serving as receivers of signals, creating a network of bulbs that could send messages to each other and connect to devices while having no discernible effect on room lighting. The bulb networks demonstrated the ability to support the low bandwidth applications typical of many devices. The VLC system may offer a low-cost, nonintrusive way to extend device-to-device communication to room area networking. "LED light bulbs mounted on the ceiling or in free-standing floor lamps easily cover a room, serving as illumination while at the same time creating a room-area network that allows data exchange between light-emitting devices," said Markus Gross, vice president at Disney Research, adding that even if the bulb is switched off, it can still serve as a receiver of signals from those devices. In the future, EnLighting may provide a practical way to connect the many devices, such as appliances, wearable devices, sensors, toys and utilities, that could comprise the Internet of Things (IoT). EnLighting can support low-bandwidth communication services beyond the room via a gateway, providing the basis for applications such as a location-based service. "Interconnecting appliances, sensors and a wide variety of devices into the Internet of Things has many potential benefits, but using radio links to do so threatens to make the radio spectrum an even scarcer resource," said Gross. "Visible light communication networks conserve the radio spectrum, while also making it difficult to eavesdrop for anyone out of line of sight of the network." The research was presented at the IEEE International Conference on Sensing, Communication and Networking (SECON) 2016. This video describes EnLighting, an indoor visible light communications system.