Using Visible Light for Joint Communications and Vibration Sensing in Industrial IoT Applications

The industrial Internet of Things (IoT) is becoming a core component of future industrial automation supporting smart manufacturing systems. One of the main building blocks here is the continuous health monitoring of the working machinery. Very recently, the use of strobing light in combination with cheap low-Frames Per Second (FPS) camera has been suggested as a non-invasive but very accurate measurement technology. We combine the sensing task with data communication using the same LED light sources. Indoor Visible Light Communication (VLC) is already popular as it helps reducing load on the quite crowded RF spectrum. In this work, we not only make use of the on-phase of the LEDs producing the strobing light for VLC-based data communication but also combine it with Dark Light Communication (DLC) in the off-phase. Here, only very short light pulses are used for communication, which cannot be seen by the human eye. The challenge was to maintain a constant energy envelope of the light signal for the camera-based frequency detector. We present now a fully-featured Visible Light Communication and Sensing (VLCS) system for application, e.g., in industrial environments.