Op weg naar Inzetbare Batterijloze Draadloze Systemen

The Internet of Things (IoT) embeds sensing, computation and communication capabilities into physical objects to enable large-scale monitoring across domains such as environmental science, infrastructure, agriculture and urban systems, but as these deployments grow in scale, their long-term sustainability, reliability and availability become critical concerns. Today, most IoT systems rely on batteries, which impose recurring maintenance costs, limit deployment lifetime and create a significant environmental burden when used at scale. These challenges are particularly acute in remote, hard-to-reach or long-lived deployments, where manual intervention is impractical. Addressing these limitations requires rethinking how wireless systems are powered and operated, motivating a shift toward battery-free IoT devices that harvest energy from their environment and operate autonomously over extended periods. Operating IoT devices without batteries introduces fundamental challenges that affect nearly every layer of the system. In battery-free architectures, energy is harvested from ambient sources such as light or motion and stored in small capacitor-based buffers, whose limited capacity and non-linear behavior constrain how energy can be accumulated and used. As a result, devices may experience frequent power interruptions, making it difficult to execute sensing, computation, and communication tasks reliably. Conventional IoT hardware, software and networking protocols are typically designed under the assumption of continuous power availability and therefore perform poorly under these conditions. Achieving dependable, long-term operation in battery-free systems thus requires approaches that explicitly account for energy variability and align system behaviour with the dynamics of the harvested energy supply. This PhD explores how battery-free wireless systems can be designed to operate reliably under these constraints by jointly considering energy harvesting, energy storage and system behaviour. Rather than treating energy availability as an external limitation, the work investigates how hardware and software can be co-designed to adapt sensing, computation and communication to the energy that is actually available. The research spans modular support for battery-free operation on commodity IoT platforms, adaptive scheduling mechanisms that align task execution with harvested energy, and energy-aware communication strategies that cope with intermittent connectivity. Together, these efforts examine how battery-free systems can move beyond fragile prototypes toward robust, reusable platforms capable of supporting diverse applications. This work is validated through extensive experimental evaluation across heterogeneous hardware platforms, deployment environments, and usage scenarios, including long-term outdoor sensing and mobile communication. The results demonstrate that battery-free systems can sustain reliable operation despite fluctuating energy availability and, in some cases, match or exceed the performance of battery-powered alternatives. By grounding the research in real-world deployments rather than short-term laboratory studies, this work provides practical insights into the design and operation of long-lived energy harvesting systems. Overall, the thesis advances battery-free wireless technologies toward dependable, scalable IoT deployments that reduce maintenance effort and environmental impact.