Selecting the best model for monitoring industrial machines is challenging due to limited data and varying conditions. While deep learning (DL) is often considered ideal, it does not always perform well. We compared DL with traditional methods focused on feature extraction and classification. Our tests on seven datasets revealed that traditional methods are more reliable when machine conditions change, highlighting the importance of simpler, interpretable models for industrial monitoring.

Robust and interpretable machine learning algorithms, which have been proven in various applications, often lack efficient implementation on limited hardware. The novel approach is to convert the inference of the interpretable ML into a deep neural network, which is efficiently executable on edge hardware. This approach was validated in terms of runtime efficiency, memory requirements, and accuracy and resulted in a significant improvement in terms of runtime and memory requirements.

Photo-thermal actuation and laser Doppler vibrometry enable fast, contactless characterization of MEMS (microelectromechanical system) resonators already before electrical connections are made. This paper details a tailored setup combining a precision stage, vacuum chamber, laser diode, and vibrometer to analyze silicon MEMS devices on a wafer level. Tests reveal how silicon device layer thickness affects resonance frequency and identify dominant loss mechanisms in different vibrational modes.

Globally, water has been the cause of the rise of civilization and also a cause of conflict. In this changing climate, managing water, the most precious commodity, has become a necessity. If we want to manage a resource properly, we need technology and data. With the innovative WAMO 300, a decentralised solution for this problem has been provided. WAMO 300, short for Water Monitor 300, acts as an IoT (Internet of Things) system that brings data from the physical world to the digital world.

This project developed a low-cost, real-time portable device for measuring radiation. The device is based on a camera similar to those used in modern smartphones and includes the ability to connect to the internet, allowing users to access data through any web browser. The program files are available for download for educational purposes.

We present a sensor with an original architecture for gas sensing that is 4 times more efficient than other sensors based on the same detection technology. It has a small volume (less than 1 cm³), low cost, and low power consumption, making it possible for it to be used in compact systems and even in smartphones. It is able to detect small changes in carbon dioxyde concentrations in ambient air for indoor air quality monitoring.

This research presents a capacitive displacement sensor concept, designed for integration into a pin array gripper. The design is optimised for additive manufacturing, offering new design possibilities and enabling the creation of fully additive manufactured pin grippers with integrated displacement sensors. A prototype sensor was fabricated using additive manufacturing, and experimental results confirm the simulations and the functionality of the fabricated sensor for different pin materials.

Continuous odor monitoring is becoming increasingly important. Therefore, odor monitoring systems are needed that are less expensive than conventional laboratory equipment and do not require trained personnel. Here, a gas chromatography selective odorant measurement sensor array (GC-SOMSA) system is used as part of the development concept. It correlates a sensor response to a mass spectrometer signal and an odor impression. This allows for a fast and inexpensive characterization suitable for many applications.

A simple and cost-effective MIP-based sensing system for the colorimetric detection of 2-methoxphenidine (2-MXP) was demonstrated. Unlike typical colorimetric systems that rely on spectrometers, this system utilizes an RGB sensor and an LED. Constructed from readily available commercial components, it can be manufactured in a standard lab environment. The system detects 2-MXP in aqueous solutions at concentrations below 1 mM and can distinguish between concentrations of 1, 0.5, 0.25, and 0.1 mM.

We developed a measurement system to improve sand core production in foundries. Sand cores are essential for creating complex shapes in metal casting. Our system uses ultrasound waves to monitor the curing process, indicating how much of the catalyst remains in the exhaust gas. This real-time monitoring allows manufacturers to optimize the process, reducing waste and enhancing product quality. We tested the system on a lab-scale core-making machine and demonstrated its effectiveness.

In a miniaturized gas chromatography system, there could be identification doubt between compounds eluting at close retention times. When a sensor is a thermal conductivity detector (TCD), we investigated a double-measurement approach (two temperatures) to improve specificity. Unfortunately, both theory and experiments showed that this method could only work for relatively high compound concentrations (1–50 ppm). This is therefore not relevant for a trace analysis system (1–10 ppb).

Some air pollution gases, such as nitrogen dioxide, are toxic at very low concentrations, highlighting the need for extensive research on materials with high sensitivity. Carbon nanotubes are nanomaterials capable of sensing toxic gases in very low concentrations. Their integration into sensors remains challenging, due, in part, to their small dimensions. This work represents a study that tests a method of safely and efficiently localizing carbon nanotubes for their integration into sensor devices.

The paper outlines a do-it-yourself optical sensor system for measuring water colour that can be used in citizen science projects to engage laypersons in science. The automated optical sensor system uses a camera with a Raspberry Pi computer to determine water colour according to the Forel–Ule colour scale. The collected data can be shared to the EyeOnWater database and used to provide insight and knowledge for further research in the fields of limnology and oceanology.

This study demonstrates how integrating silicon mechanical sensors into composites enables the detection of internal structural variations and how this can find applications in process monitoring or structural health monitoring (SHM). It introduces a novel, minimally intrusive process for embedding sensors within composites by means of a substrate-free transfer technique. Temperature and strain effects are studied. The sensor exhibits high sensitivity and is able to detect a creep effect at the core of the composite.

We present a new method for creating flexible temperature sensors that can be applied to complex shapes. By using a technique called water transfer printing, these sensors can be transferred directly onto surfaces without the need for flexible films . This allows them to be more accurate, more reliable, and more adaptable than traditional sensors.  These sensors can work well in various environments and are unaffected by humidity, making them ideal for use in healthcare, robotics, and wearable devices.

In many investigations of piezoelectric energy harvesters, it is often tacitly assumed that optimal performance is achieved when the vibration mode of the structure ensures a uniform strain within the piezoelectric layer. This manuscript provides, for the first time ever, a rigorous proof of this point.

In this study, we consider the planform of a cantilever piezoelectric vibrating energy harvester (PVEH) device in which the inertia of the cantilever itself is dominant relative to the inertia of an edge block. We derive the optimal planform which ensures the harvested energy is maximal. We show that the contours of the optimal planform are defined by Bessel functions. The predictive capabilities of our model are demonstrated by comparison to finite-element simulations.

This research investigates the use of Capacitive Micromachined Ultrasonic Transducers (CMUTs) for underwater object detection and mapping in shallow-water environments. Experiments demonstrated their ability to detect small objects ( up to 4mm in size) and accurately reconstruct complex 3D surfaces. The findings highlight their potential for high-resolution underwater applications, especially for those requiring economic, compact, portable solutions.

Parasitic direct currents in our alternating-current power grid affect the operation of power transformers. In this work, we present a fiber-optic current sensor system designed for the long-term monitoring of such direct currents, especially those arising from solar activity. The sensor demonstrator allows remote data access and sensor operation and was deployed at an electrical substation. For the first time, we show measurements of such currents on single phases of the power grid.

Bistability is a mechanical phenomenon resulting in two stable, switchable states similar to a light switch. Micromachined piezoelectric bistable loudspeakers can utilize this effect to generate ultrasonic pulses with substantial loudness for applications such as distance measurements. In this work, we study different aspects of such a micromachined ultrasonic loudspeaker and demonstrate that such a device is feasible for ranging applications.

While electronic noses are designed to detect volatile organic compounds (VOCs) in complex odors, materials within sampling chambers and lines can emit their own gases, altering sensor responses. Our study confirmed that silicone and 3D-printed resin release compounds that poison sensors and reduce life span. In contrast, polyetheretherketone (PEEK) is a stable material that does not cause poisoning. Understanding these effects is crucial for designing reliable gas sensing platforms, ensuring accurate gas detection in different applications.

The concept of an innovative energy harvester that could combine piezoelectric and reverse electrowetting-on-dielectric (REWOD) techniques is presented. By harnessing biomechanical vibrations from the cardiovascular system with piezoelectricity and a REWOD unit, the overall power output of the harvester was enhanced. This contributes to the advancement of self-powered, sustainable, wearable biosensors, enabling seamless and continuous data acquisition without relying on external batteries.

In this article we present a new method to measure the flow of a gas by means of ultrasound waves. Instead of sending pulses across the cross-section of the pipe, we make ultrasound travel along the length of the pipe. In other words, the pipe becomes an acoustic waveguide. This has the advantage that the travelling distance can become much longer, and so the measurement of the transit time becomes more sensitive to changes in the flow or the speed of sound.

We present an automated, contactless method to map thin film thickness and stress across microelectromechanical systems (MEMS) wafers. Using white light interferometry on cantilevers and step profiles, we extract both mean and gradient stress with orientation sensitivity. Applied to six thin films, the approach reveals process-dependent variations, offering a reliable tool for evaluating and comparing MEMS materials and fabrication methods.

This research improves the performance of microbridge resonators for various applications, including gas sensing. By strategically designing the bottom electrode size relative to the microbridge length while keeping all other design parameters constant, the required operating voltage is reduced without compromising performance. Advanced modelling and experimental results demonstrate a 16 % reduction in operating voltage. These findings enhance resonator efficiency across diverse applications.

More traffic leads to more accidents involving wildlife, especially on rural roadcuts through habitats. Solutions like wildlife bridges and fences are needed, but there is no comprehensive solution yet. We have developed a system to detect and assess wildlife, including deer. This technology can work at night and in fog as animals cross roads in poor visibility. Radar sensors and infrared cameras are our solution.

Humans continue to use various units of measurement that are outside the internationally accepted System of Units (SI). This creates confusion that machines are unable to overcome. In the future, machines and sensor systems feeding data to those machines are expected to operate exclusively using the SI. This requires an internationally authoritative database for converting the non-SI units that humans enter to SI units at the level of the human–machine interface or human–sensor interface.

This article presents first results from our research on the improvement of post-consumer recycled plastics in a suitable measurement situation on the compounding extruder, where the material is molten and by-products are removed by a vacuum. An extraction system was implemented, and samples were analyzed with laboratory methods. The results give insight into occurring substances and show the feasibility of the technique. Guidelines for an online sampling and monitoring system are derived.

Scanning electron microscopy (SEM) and atomic force microscopy (AFM) enable sub-nanometer surface imaging and complement each other's limitations. Integrating AFM into a SEM vacuum chamber combines their strengths. However, vacuum increases the cantilever's Q factor and reduces scan speed. We develop a feedback circuit and a piezoelectric MEMS cantilever to tune the Q factor, enabling vacuum AFM at air-like speeds.

This paper is related to a theoretical background and the performance testing of lateral position sensing based on quadrature spatio-temporal modulation with adaptive parameter correction, implemented in a prototype micropower optical position sensor. There is a substantial improvement in position readout accuracy over a basic detection method (0.2 mm for sensing gaps >100 mm), and elevated tolerance to harsh field conditions (e.g. partial blockage in optical paths) has been demonstrated. 

We developed a simple and versatile sensor that can detect harmful substances more effectively. By improving how the sensor's key component, the membrane, is made, we matched it better with the materials used to capture target chemicals. This makes the sensor easier to build and more reliable. Our work shows how choosing the right membrane material can greatly improve performance, opening the way for broader applications in detecting pollutants.