We describe a mechanical model based on the beam theory for the development of a beam-like sensor switch with switching hysteresis for humidity sensing. The hydrogel swelling provides the mechanical energy to deflect the partly hydrogel-covered bending beam via the bimorph effect. From the model, we calculate the deflection of a beam-like sensor switch with and without a switching hysteresis. A beam-like sensor switch was manufactured, and the switching hysteresis was successfully demonstrated.

In this work, genetically modified cells of the yeast Saccharomyces cerevisiae BY4741 were confined in a four-chamber microfluidic cell, providing an optical monitoring of the cell behaviour and their supply with the nutrients. The measurements of the time-dependent fluorescence intensity were performed with different concentrations of the drug diclofenac, and the sensitivity of yeast cells to diclofenac was demonstrated. Cell viability was monitored by simultaneous impedance recording.

We describe a low-cost sensor for the detection of ethanol in alcoholic beverages. The reversible swelling of alcohol-sensitive hydrogels depends on the ethanol concentration. The resulting swelling pressure was detected via piezoresistive sensors. We have tested the swelling properties of the hydrogel (e.g. swelling kinetics, selectivity to other alcohols). Furthermore, the first sensor set-ups were tested and the reversibility of the hydrogel-based piezoresistive sensor was demonstrated.

The inline monitoring of parameters in aqueous liquids is facing an increasing demand in many application areas. In this paper we report on an optical monitoring of the pH value in liquids by means of a sensitive hydrogel, which can be applied in the physiological range. Our results indicate a nearly linear dependency between pH value and hydrogel swelling. Furthermore, we show an improvement of the response time by a factor of 2 in comparison to other systems exploiting this kind of hydrogel.

The presented work gives insight into the behaviour of co-resonantly coupled oscillating cantilever beams by means of electro-mechanical analogies. An electric circuit model is analysed with various stages of complexity, and conclusions are drawn regarding the applicability of the co-resonant concept for sensors. Furthermore, this is validated by a comparison between the theoretical predictions and experimental data.

Piezoelectric devices are characterized non-destructively to ensure their functionality. The material is heated by laser diodes. The resulting temperature changes lead to a pyroelectric current. Analytical and numerical finite element models describe the temperature distribution and the current in frequency and time domain. Modelling and experimental results are compared for piezoelectric plates and integrated sensors and actuators.

Hydrogels are swellable polymers, which exhibit superior sensor properties. However, the exploitation of these properties for innovative measurement technology has been prevented by the lack of a manufacturing technique for thin hydogel films that suits industrial needs. We suggest a paradigm change from the current recipe-driven sensor manufacturing to a specification-driven one. Our contributions are optimized processes for a controllable film formation and thermal curing of the hydrogels.

Infrared cameras based on microbolometer focal plane arrays (FPAs) are the most widely used cameras in thermography. For acceptable measurement uncertainty values, the disturbing influences of changing ambient temperature have to be considered. We propose a TEC-less and shutter-less correction approach based on additional temperature measurements inside the IR camera. The effects on the pixel responsivity and offset voltage are considered separately.