Distributed embedded systems are pervasive components jointly operating in a wide range of applications. Moving toward energy harvesting powered systems enables their long-term, sustainable, scalable, and maintenance-free operation. When these systems are used as components of an automatic control system to sense a control plant, energy availability limits when and how often sensed data are obtainable and therefore when and how often control updates can be performed. The time-varying and non-deterministic availability of harvested energy and the necessity to plan the energy usage of the energy harvesting sensor nodes ahead of time, on the one hand, have to be balanced with the dynamically changing and complex demand for control updates from the automatic control plant and thus energy usage, on the other hand. We propose a hierarchical approach with which the resources of the energy harvesting sensor nodes are managed on a long time horizon and on a faster timescale, self-triggered model predictive control controls the plant. The controller of the harvesting-based nodes’ resources schedules the future energy usage ahead of time and the self-triggered model predictive control incorporates these time-varying energy constraints. For this novel combination of energy harvesting and automatic control systems, we derive provable properties in terms of correctness, feasibility, and performance. We evaluate the approach on a double integrator and demonstrate its usability and performance in a room temperature and air quality control case study.

Wireless sensors form an integral part of the Internet of Things (IoT), standing at the edge between the cyber and physical domains. Ac-quiring and transmitting environmental data is an energy-intensive workload, especially when considering networks spanning large buildings or even cities. Many works aim to integrate energy har-vesting into wireless sensors, providing them with a greater level of energy autonomy. Initially deployed for energy-rich outdoor environments, recent advances have allowed wireless sensors to efficiently utilize the reduced energy harvested in indoor lighting conditions. This demo introduces a harvesting-based Dual Proces-sor Platform, the DPP3e, designed for energy harvesting in indoor environments. It features various sensors for advanced indoor en-vironmental sensing, e.g. air quality measurements, a low-power display for immediate visual feedback, and a powerful micro controller for energy-efficient inference of Tensorflow models. Fur-thermore, it has two separate RF interfaces: a 2.4 GHz Bluetooth Low Energy (BLE) radio for short-range communication, and a sub-GHz transceiver for long-range communication. Using configurable power domains and advanced power management, it can sustain sending BLE packets every 5 seconds while consuming only 37 µ W.

With the Internet of Things (IoT) large amounts of data can be gathered at the edge, centrally collected and subsequently utilized for various application domains. Efficient and reliable synchro-nous communication protocols are essential for automated data gathering, yet they typically require a stable energy supply. En-ergy harvesting enables long-term deployments, but it imposes widely varying energy budgets on each node in the network. To re-main efficient, synchronous protocols need to consider this energy variability. We propose a selective flooding protocol that employs low-energy communication rounds for all nodes and additional high-energy rounds only for nodes with high input power thus increasing their throughput. Low-energy rounds gather data with high reliability and maintain global network synchronization, while high-energy rounds use increased transmit power to overcome potentially-broken links that depend on low-power nodes. We eval-uate our proposed method on the FlockLab testbed and build a small network composed of standalone energy harvesting nodes. The average power consumption of almost 84 µW and 177 µW for low- and high-power nodes, respectively, are fully sustainable by indoor photovoltaic harvesting.

Employing energy harvesting to power the Internet of Things supports their long-term, self-sustainable, and maintenance-free operation. These energy harvesting systems have an energy management subsystem to orchestrate the flow of energy and optimize their achievable system performance. Numerous such algorithms for a single harvesting-based system have been proposed. When envisioning the joint use of multiple distributed energy harvesting nodes in a single application, the performance and behavior of the distributed system depends on the mutual energy availability and therefore energy management of all nodes. We propose to perform the energy management of multiple distributed energy harvesting nodes jointly and thus, optimize the distributed system's performance as opposed to the performance of each energy harvesting node individually. We demonstrate the novel joint optimization in a scenario with multiple energy harvesting nodes and observe that the distributed system's performance improves by 28 % compared to when each node's energy is managed individually.

In this work, we show that sensor data may leak a sensor's location even if the latter is not explicitly included in the data set. The sensors are localized by linking sensor data, in particular activity data, with publicly available environmental data such as weather data. We show that using a linkage attack a cow can be localized within an entire country with an average accuracy of up to 32.6 km solely from activity traces recorded with a tracker in the cow's stomach.