Patrik Jacko

Bistable amorphous microwires enable time-domain sensing through abrupt magnetization switching but typically require complex electronic interfaces with bipolar supplies. This paper presents a single-chip bistable microwire sensor interface based on the STM32G474RE microcontroller using a bifilar excitation coil to generate an effective bipolar magnetic field from a unipolar supply, eliminating the need for DC–DC converters, symmetrical power rails, and external amplifiers. Experimental results demonstrate reliable microwire switching and linear displacement measurement over an 5.25 mm range with a resolution down to 10 μm. The proposed solution significantly reduces component count, size, and complexity, making it suitable for embedded and IoT applications.

This is the first-ever report on successfully igniting a mixing-induced self-propagating reaction (MXSR) for an inorganic system just by simple intensive mixing. Namely, mixtures of nanocrystalline copper sulfides covellite (CuS) and digenite (Cu1.8S) were prepared within two minutes of intensive mixing of copper and sulfur powders utilizing a ball-free planetary ball mill jar as a reaction vessel. The content of digenite and covellite can be controlled by experimental conditions, e.g., providing sulfur over-stoichiometry leads to covellite with higher phase purity. The MXSR ignition was precisely determined utilizing a self-made in situ temperature monitoring device. For the MXSR to occur under the ball-free conditions, the following conditions are needed: jar filling ratio at least 40%, rotation speed at least 700 rpm and Cu:S molar ratio in the range between 0.625 and 1.00. When MXSR is not ignited, the powder after intensive mixing contains a mixture of digenite and non-reacted sulfur, which is transformed into covellite with time. In specific cases, the MXSR is ignited within a few minutes after the termination of mixing. The scalability of the proposed methodology is verified on the 40 and 62.5 g scale utilizing a planetary and mixer mill, respectively. The present approach is in great alignment with green chemistry principles, since it utilizes only atoms composing the product, does not create any waste and can be ignited in the absence of external heating or mechanical input which distinguishes it from self-propagating high-temperature synthesis and from mechanically induced self-propagating reaction. Moreover, the absence of milling media eliminates contamination from jar and ball abrasion. Finally, thermoelectric measurements show that the as-prepared copper sulfides can be directly processed into functional materials for waste-heat-to-electricity conversion, offering a promising basis for further optimization.

Visually impaired individuals face challenges in mobility, object recognition, and text reading. Existing assistive tools provide partial solutions but lack full integration. This paper presents a low-cost, multifunctional assistive device in the form of wearable glasses, integrating real-time text recognition, obstacle detection, and remote assistance. Built around a Raspberry Pi Zero 2W, the system features an Arducam IMX519 autofocus camera and a tactile button interface for user-friendly control. Real-time audio feedback enhances situational awareness, promoting greater independence. The device was tested at the Rehabilitation Center for the Visually Impaired in Levoča. Performance evaluations confirm high text recognition accuracy and improved navigation support. A comparative analysis highlights its affordability and functionality over commercial alternatives. While effective, the device requires processing speed optimization and hardware miniaturization. Future improvements will explore haptic feedback and AI-driven scene analysis to enhance usability. This research contributes to affordable and inclusive assistive technology, improving accessibility for visually impaired individuals.

The paper focuses on the measurement of PM and other meteorological parameters in a small region of central Europe—eastern Slovakia and northeastern Hungary. Due to the increasing availability of sensors measuring not only PM, but also temperature, humidity, pressure, VOC, NOx, and CO₂, new possibilities arise in terms of comparing (mainly in terms of correlation) PM and the other measured parameters, thus generating a large amount of data for evaluation. The correlations found are typical for inland conditions, thus able to map other regions of the world. The presented measurements can also be used to predict the evolution of PM with alerts for people with respiratory diseases, or in virtual reality using a digital twin of a humanoid robot.

The advantageous applications of magnetic bistable microwires have emerged during long-lasting research. They have a wide range of applications in the scientific sphere or technical practice. They can be used for various applications, including magnetic memories, biomedicine, and sensors. This manuscript is focused on the last-mentioned application of microwires—sensors—discussing various digital signal processing techniques used in practical applications. Thanks to the highly sensitive properties of microwires and their two stable states of magnetization, it is possible to perform precise measurements with less demanding digital processing. The manuscript presents four practical signal-processing methods of microwire response using three different experiments. These experiments are focused on detecting the signal in a simple environment without an external magnetic background, measuring with the external background of a ferromagnetic core, and measuring in harsh conditions with a strong magnetic background. The experiments aim to propose the best method under various conditions, emphasizing the quality and signal processing speed of the microwire signal.

The paper deals with a brief overview of magnetoelastic sensors and magnetoelastic sensors used in general for sensing bending forces, either directly or sensing bent structures, and defines the current state of the art. Bulk magnetoelastic force sensors are usually manufactured from transformer sheets or amorphous alloys. In praxis, usually, a compressive force is sensed by bulk magnetoelastic sensors; however, in this paper, the sensor is used for the measurement of bending forces, one reason being that the effect of such forces is easily experimentally tested, whereas compressive forces acting on a single sheet make buckling prevention a challenge. The measurement of the material characteristics that served as inputs into a FEM simulation model of the sensor is presented and described. The used material was considered to be mechanically and magnetically isotropic and magnetically nonlinear, even though the real sheet showed anisotropic behavior to some degree. A sinusoidal magnetizing current waveform was used in the experimental part of this paper, which was created by a current source. The effects of various frequencies, amplitudes, and sensor geometries were tested. The experimental part of this paper studies the sensors’ RMS voltage changes to different loadings that bend the sheet out of its plane. The output voltage was the induced voltage in the secondary coil and was further analyzed to compute the linearity and sensitivity of the sensor at the specific current characteristic. It was found that for the given material, the most favorable operating conditions are obtained with higher frequency signals and higher excitation current amplitudes. The linearity of the sensor can be improved by placing the holes of the windings at different angles than 90° and by placing them further apart along the sheet’s length. The current source was created by a simple op-amp voltage-to-current source controlled by a signal generator, which created a stable waveform. It was found that transformer sheet bending sensors with the dimensions described in this paper are suitable for the measurement of small forces in the range of up to 2 N for the shorter sensors and approximately 0.2 N for the longer sensors.

The energy crisis is a massive problem in today's world. Conventional energy sources are not only limited but also major contributors to environmental pollution. Renewable energy sources are becoming priorities worldwide. To reduce dependence on conventional energy sources, it is necessary to explore alternative options. Solar energy is rapidly gaining attention as an important means of expanding the use of renewable energy. Solar cells, which convert solar energy into electrical energy, are expensive and relatively inefficient. Various mechanisms and systems are used to increase the efficiency of solar cells and maximize energy generation. A solar tracking system is used to enhance the efficiency of solar cells by tracking the movement of the sun. This article describes the methodology for designing an automatic solar tracker based on the ESP32 microcontroller. Light-dependent resistors (LDRs) are used as sensors to detect the current position of the sun. The proposed tracker has a precise control mechanism that adjusts the orientation of the solar panel based on the measured values from the LDRs to achieve the optimal position perpendicular to the sun, ensuring the highest productivity in energy generation. The result is a constructed small-scale prototype of a solar tracking system, along with a description of its components and the programming part.

This article describes in detail the implementation of an automated parking house model based on ATmega2560 microcontroller that enables simple and efficient parking of cars in precisely determined positions. Described model offers to user convenient parking of the car model. In addition to the automated parking system, the system provides several additional functions realized by displacement sensors and smoke sensors. One of the goals of this paper is to eliminate potentially dangerous situations and collisions during parking and thereby increase safety in this area. The garage house model is not designed solely for parking purposes but also as a practical teaching tool in the field of sensors and actuators. It is precisely in this area that students can expand their skills in designing and implementing programs that can enable all the functions of the garage house - temperature and smoke detection, precise positioning of the platform through stepper motors, display outputs, and more. At the same time, they will learn teamwork, where the functionality of the garage house is divided into multiple parts, and individual teams of students must collaborate to successfully solve and create a fully functional garage house software.

The article describes the design of a universal simulation model of a voltage regulator for applications compatible with the globally used PSpice program. Users can create a model of any type of integrated switching voltage regulator that is currently available on the market by setting its individual parameters. The proposed connection of the regulator was applied in the connection of the buck DC–DC converter. The accuracy of the model was verified by comparing the results obtained by the simulation to other official models and to practical measurements taken on a real sample of the converter. The versatility of the model was proven by comparison with another type of converter with different parameters.

The article describes the implementation of IoT technology in the teaching of microprocessor technology. The method presented in the article combines the reality and virtualization of the microprocessor technology laboratory. A created IoT monitoring device monitors the students’ microcontroller pins and sends the data to the server to which the teacher is connected via the control application. The teacher has the opportunity to monitor the development of tasks and student code of the program, where the functionality of these tasks can be verified. Thanks to the IoT remote laboratory implementation, students’ tasks during the lesson were improved. As many as 53% (n = 8) of those students who could improve their results achieved an improvement of one or up to two tasks during class. Before the IoT remote laboratory application, up to 30% (n = 6) of students could not solve any task and only 25% (n = 5) solved two tasks (full number of tasks) during the class. Before implementation, 45% (n = 9) solved one problem. After applying the IoT remote laboratory, these numbers increased significantly and up to 50% (n = 10) of students solved the full number of tasks. In contrast, only 10% (n = 2) of students did not solve any task.