The purpose of my dissertation was to develop a „Place and Forget” sensor node, suitable for continuous monitoring of different structural elements in civil engineering without the need of an external power supply, or other wired communication. The observed parameters were the temperature as well as the strain, which may of course be a result of thermal expansion, twisting force, or other external effects.
In the thesis, I describe how the solar cells are operating, and introduce the relevant parameters. Besides I present the strain gauging foils and the basics of the various thermometer modules. For the measurement, it is also necessary to adress the temperature compensation during the measuring process, since it has a huge impact on the results.
The PCB designing process is also described, where I present how to satisfy the low energy consumption, which of course is just as much of a firmware job, as a hardware task. Therefore I mention a few words about the firmware as well. Besides the wireless communication moduls are also introduced.
And finally I discussed about the enclosure design, where compactness is an important aspect, as well as weather resistance and maintainability.
Testing was also an important task, so I am also presenting the process of it and the results of the tests.