This study presents the practical realization of a digital vibration absorber that, owing to the flexibility provided by the digital unit, synthesizes linear and nonlinear shunt circuits. The absorber, composed of a microprocessor and a current source, is connected to the host structure with piezoelectric patches. The performance of both circuits is compared experimentally for a nonlinear host structure. The superiority of a properly-tuned nonlinear absorber over its linear counterpart is validated, but the limits of the nonlinear absorber are also explored. Moreover, the accuracy of the tuning procedure and formulas is assessed through experimental parametric studies.

In this study, a digital impedance is used to realize both a linear and a nonlinear piezoelectric tuned vibration absorber in order to mitigate the vibrations of a nonlinear structure. The digital processing unit enables the synthesis of impedances with arbitrary functional forms, thereby easing the implementation of nonlinear absorbers. The superior performance of the nonlinear absorber over its linear counterpart is demonstrated experimentally. Various nonlinear functional forms are also tested in the absorber and illustrate the relevance of the principle of similarity (i.e. the same nonlinear functional form as that in the host structure should be used in the absorber).

The increasing availability of low-cost sensors and open source projects make it easier than ever for a maker to build his own air quality node. Nonetheless, depending on one’s goal and its related data quality objective, to customize an existing project or to build a specific printed circuit board may still be very useful. In the framework of the Outdoor and Indoor Exposure project, a portable mini-station has been developed, tested and then used in two experiments: exposure assessment and complementary network measurement. The present paper focuses on the description of the equipment that was designed and prototyped, as well as on the tests that were made in the lab and in the field to evaluate its overall performance and that of its different sensors. Finally, we present what we consider to be its main drawbacks and our perspectives for further development and tests.