Intentionally imperfect sensors for measuring mechanical parameters

While modern sensors benefit from increasing precision by permanently shrinking dimensions, we have focused on the opposite way of thinking and developing. Although, coming from the MEMs branch we developed sensors with millimeter sized dimensions for the detection of mechanical parameters. Main key of our investigations is the intentionally imperfectness of the sensors. From this point of view, we have considered the question: Would it be possible to generate electrical sensor signals allowing for a high quality determination regarding mechanical loads? Change of capacitance by external mechanical forces is the basic measuring principle used in our development. The sensors consist of PDMS membranes filled with randomly distributed spheres of steel. Above the membrane, an interdigitated electrode structure is positioned. Just slight moves of the spheres by external mechanical forces change the field distribution and therefore the capacitance. Differences between common known sensors and our developments are in the complexity of fabrication technology and precision. In our investigations, we found that it is possible to detect accelerations or slops even if the sensing systems consists of randomly distributed functional elements. Moreover, the sensitivity of the sensors was comparable with extreme sensitive devices available on the market.