Disney's light-bulb moment: build TCP into LEDs for IoT comms

It's going to be the year of Linux in the light socket

Since lights are everywhere, and LED lamps are The Way of The FutureTM, it makes sense that they be used for communications. Now, boffins working for Disney Research have taken LED-based comms a step further, adding a Linux TCP/IP network stack to a consumer lamp.

Their work, published here, pushes visible light communication (VLC) beyond research that has focussed on physical- and MAC-layers with a custom-built board the researchers reckon could be cheaply and easily integrated into existing LED lamps.

Doing so, they write, means integrating the inter-Thing communication with the TCP/IP protocol, and getting the protocol running under a familiar operating system (in this case, Linux).

To do that, the boffins working at ETH Zurich for Disney Research built a bottom-to-top stack instead of merely demonstrating that ones-and-zeroes sent by one lamp could be received by another. This includes:

  • Hardware design to turn a consumer LED light bulb into a Linux host;
  • A Linux kernel module that integrates the VLC protocol's physical and MAC layers into the Linux networking stack; and
  • Evaluation of the system using ICMP, UDP, and TCP.

An 8-bit Atmel controller handles the PHY and MAC layer protocols on the lamp, with an Atheros AR9331 system-on-a-chip running OpenWrt providing the on-lamp Linux environment.

The advantage of creating a full-stack implementation, the paper says, is that individual lamps are able to route data, rather than merely supporting simple point-to-point links.

Additionally, they note, the VLC network can operate without needing the other communication channels proposed for the Internet of Things (such as ZigBee, Wi-Fi, or Bluetooth).

And, of course, anything that can flash an LED on and off could be used to support the communication system: “Endpoints can be light bulbs or other platforms that provide LED-based communication equipped with a compatible IP stack,” the paper notes.

Disney Research light-bulb comms module

Packing it in: the comms module including (1) power supply, (2) SoC board and (3) VLC controller. Image: Disney Research

The setup is only capable of 1 Kbps at the moment, something the researchers acknowledge needs work.

And since this is Disney, the merchandising opportunities are never far away: “Communication with light enables a true Internet of Things, as consumer devices, such as toys equipped with LEDs, are transformed into interactive IP communication nodes”, the paper concludes. ®

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