Powering the Internet of Things Through Light Communication

© 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Novel solutions are required to connect billions of devices to the network as envisioned by the IoT. In this article we propose to use LiFi, which is based on off-the-shelf LEDs, as an enabler for the IoT in indoor environments. We present LiFi4IoT, a system which, in addition to communication, provides three main services that the radio frequency (RF) IoT networks struggle to offer: precise device positioning; the possibility of delivering power, since energy can be harvested from light; and inherent security due to the propagation properties of visible light. We analyze the application space of IoT in indoor scenarios, and propose a LiFi4IoT access point (AP) that communicates simultaneously with IoT devices featuring different types of detectors, such as CMOS camera sensors, PDs, and solar cells. Based on the capabilities of these technologies, we define three types of energy self-sufficient IoT "motes" and analyze their feasibility. Finally, we identify the main research directions to enable the LiFi4IoT vision and provide preliminary results for several of these.Peer ReviewedPostprint (author's final draft

Optical autonomous sensor module communicating with a smartphone using its camera

Wireless optical communication is a viable alternative to conventional RF technology. Our novel design combines optical communication and energy harvesting in one device with a size of 30 x 10 x 5 mm using the latest innovations in lowpower electronics and solar cell technology. In our study, we implement visible light communication between a sensor module and a smartphone. The proposed system design and a communication protocol are specifically developed for environments with illumination levels of 100-500 lux, like industrial halls. The sensor integrated into the module can vary according to application requirements. As an example, in our work, we use a temperature and pressure sensor and an accelerometer. A bright flash from a smartphones build-in LED activates the module. The module takes measurements and sends the result in form of an optical data signal, which is then received by the smartphone camera. This technique is able to provide reliable communication despite low-power restrictions of energy harvesting. By using a smartphone this approach offers more convenience to a user and enables flexible deployment of the modules in industrial machinery. © 2019 SPIE