In fact, the amount of energy harvested depends not only on environmental conditions, which can vary in a rapid and uncontrolled way, but also on the energy drawn at runtime by the powered device.
In particular, RESs show a high degree of unpredictability while EH devices provide an extremely variable efficiency.
#High power emulator software
However, designing hardware and software solutions for EH-WSNs is a difficult task due to the main characteristics of RESs. EH motes can be deployed in remote environments and they can run potentially for an unlimited amount of time by gathering solar, kinetic, radio frequencies, or thermal energy. This new opportunity has begun to shift the research paradigm from energy-constrained lifetime maximization (typical of battery-operated systems) to power-constrained workload maximization. Recent advances in energy harvesting (EH) have introduced the opportunity of granting unbounded lifetime to sensor nodes, thus overcoming the limitations of battery-operated WSNs and introducing a new class of WSNs, called EH wireless sensor network (EH-WSNs), made of motes powered by renewable energy sources (RESs). In such states, consumption drops from tens of milliwatts to a fraction of a microwatt increasing the system lifetime. The typical way of addressing this issue is by means of dynamic power management (DPM) strategies exploiting multiple low-power states of the motes.
One of the most critical issue in designing and developing WSNs is the limited amount of energy usually available in the nodes. Wireless sensor networks (WSNs) consist of a set of communicating nodes (motes) capable of sensing, processing, and storing physical quantities. The presented solution represents therefore a convenient solution for testing large-scale testbeds under realistic energy supply scenarios for wireless sensor networks. An extensive experimental characterization confirms the validity of the embedded emulator in terms of flexibility, accuracy, and latency while a case study about the emulation of a lithium battery shows that the hardware-software platform does not introduce any measurable reduction of the accuracy of the model. The proposed system consists of a modular architecture featuring small factor form, low power requirements, and limited cost. This paper introduces a novel embedded hardware-software solution aimed at emulating a wide spectrum of energy sources usually exploited to power sensor networks motes. In particular, the heterogeneity, the variability, and the unpredictability of many energy sources, combined to changes in energy required by powered devices, make it difficult to obtain reproducible testing conditions, thus prompting the need of novel solutions addressing these issues. However, the design of effective networked embedded systems targeting unlimited lifetime poses several challenges at different architectural levels.
The capability to either minimize energy consumption in battery-operated devices, or to adequately exploit energy harvesting from various ambient sources, is central to the development and engineering of energy-neutral wireless sensor networks.
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