Many applications in high-voltage environments require electrically isolated sensors. We demonstrate a purely optical sensor link using only low-cost high-brightness LEDs and only one polymer optical fiber (POF) for remote powering of isolated electronic sensor nodes of as well as for data transmission of sensor data to a central unit. No optical couplers or special photo diodes are required, to save costs and reduce size. This enables us to install sensor networks in the field with low effort.

The paper introduces a novel method for 2-D localization of a target in the indoor environment using the RSSI approach with only two sensors. The proposed method reduces the number of sensors by one compared to the trilateration method, which uses at least three sensors for 2-D localization. The achieved accuracy under the white Gaussian noise condition is about 3.4 cm as an average of all positions inside the considered simulated environment.

A new wireless communication system (WCS) for sensor-actuator communication has been developed to facilitate energy and environmental monitoring on the shop floor of industrial production sites. Its wireless technology is presented in detail. The WCS is able to efficiently use the available spectrum together with the other wireless systems around. Measured results for the coexistence capability are shown.

To promote WSNs for IoT, energy consumption must be reduced to enable more applications. The power need by a sensor node is governed by the radio component. A wake-up receiver is an ultra-low-power radio receiver. It serves for idle listening whilst leaving the node in sleep state. The main research focus of WuRxs is to reduce energy usage and to improve sensitivity. In this work, active components are carefully used to construct a 7.5 µW WuRx with −60 dBm sensitivity and a latency of 10 ms.

Many different techniques have been introduced in an effort to maximize heterogeneous wireless sensor lifespan, but these techniques have focused on having the nodes in a cluster send their data to a selected cluster head node that, in turn, reports the data to the base station. Therefore, the choice of the number of clusters and the way the cluster head node is selected are the main focuses of this research paper.