Optical autonomous sensor module communicating with a smartphone using its camera

Abstract

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.