This paper proposes an embedded Internet of Things (IoT) system for bioreactor sensor integration, aimed at optimizing temperature and turbidity control during cell cultivation. Utilizing an ESP32 development board, the system makes advances on previous iterations by incorporating superior analog-to-digital conversion capabilities, dual-core processing, and integrated Wi-Fi and Bluetooth connectivity. The key components include a DS18B20 digital temperature sensor, a TS-300B turbidity sensor, and a Peltier module for temperature regulation. Through real-time monitoring and data transmission to cloud platforms, the system facilitates advanced process control and optimization. The experimental results on yeast cultures demonstrate the system’s effectiveness at maintaining optimal growth, highlighting its potential to enhance bioprocessing techniques. The proposed solution underscores the practical applications of the IoT in bioreactor environments, offering insights into the improved efficiency and reliability of culture cultivation processes.

Efficient and safe charging of lithium-ion batteries is essential for maximizing their lifespan and performance. This paper presents the design and implementation of a microcontroller-based Li-ion battery charger that employs real-time monitoring, adaptive charging strategies, and built-in safety mechanisms. The system integrates a CC/CV charging approach with automatic current regulation, overcharge protection, and reverse polarity detection. A current sensor module ensures continuous monitoring, while an LCD interface provides real-time feedback on charging parameters. Experimental validation was conducted using multiple Li-ion cells in various conditions, like new, aged, and deeply discharged, to evaluate charging behavior and safety under different scenarios. The system successfully regulated current and voltage, managed preconditioning for low-voltage cells, and transitioned smoothly between charging phases. A key contribution of this work is the development of a low-cost, microcontroller-based platform that enables flexible implementation and testing of diverse charging strategies. Its open-source architecture and modular design make it highly suitable for research, educational use, and experimental development in battery management systems. Future enhancements may include the integration of adaptive algorithms based on internal resistance and temperature, enabling smarter and more efficient charging.

The sound speed is affected by changes in the air properties, such as temperature, pressure, humidity, gas composition, and air turbulence. It has direct influence on the accuracy of distance measuring and the sound wavelength. For many indoor applications, the sound speed in air is considered as constant. For outdoor environments, a constant sound speed generates important errors of distance estimation. Also, for low temperature values, the real distance is smaller than measured distance, and this can be a dangerous situation. The pressure influence on sound speed can be neglected, and the sound speed depends on temperature and relative humidity. In this paper, variations in the speed of sound as a function of air properties are studied, along with their influence on the accuracy of ultrasonic sensing. In addition, fuzzy rules are generated for sound speed values used in outdoor applications.

Wireless technologies are the ones who provide fast communications on long distances. MIMO (Multiple-Input-Multiple-Output) Systems become an important factor in communication standards. At the beginning, this technology involved several antennas for both transmission and reception. Nowadays, in order to improve the performance of wireless transmissions, in addition to multi-channel propagation, error correction codes are used. Golden Code has some advantages, such as: maximum rate and diversity or coding gain. In this paper it is proposed an approach of using this code to mitigate the impulsive noise effects in a MIMO communication system. The Middleton Class-A noise was considered. The simulation was done for different values of the impulsive noise model parameters and showed that the probability density function depends on index impulse and on gaussian factor and the number of noise sources has no influence.

Interleavers are important blocks from turbo codes structure, their type and dimensions having a significant influence on the performances of the mentioned codes. The permutation polynomial (PP) based interleavers lead to remarkable performances of these codes, if they are appropriately chosen. The most used interleavers from this category are quadratic permutation polynomials (QPPs) and cubic permutation polynomials (CPPs). Based on the necessary and sufficient conditions for the coefficients of third degree polynomial to be CPP, in this paper we determine the number of true different CPPs that cannot be reduced to QPPs or linear permutation polynomials (LPPs), for the lengths from the LTE standard (multiple of 8). This is of particular interest when we need to find CPP interleavers for turbo codes.

A well-known and debated topic recently is related by batteries and chargers. Batteries are used in a wide variety of fields like automotive electric vehicles where new technologies are continuously researched but also house hold items where we can find different types like li-ion and alkaline batteries. For most of the rechargeable batteries there are different types of chargers each having different features like fast charge or smart charger and so on. Like any other consumable, the battery also reaches the end of its life after a number of charging cycles or other wear factors. After the batteries degrade and can no longer be used it needs to be recycled. The recycling process is still a researched process because it also causes pollution and it is not completely green. Some of the batteries like alkaline small ones can only be used once and the manufacturer states that no one should attempt to charge a non-rechargeable battery. Well, most of them can be recharge by using a system based on a microcontroller and software that knows how to manage the current and voltage of the charging process. By managing to recharge depleted batteries can also contribute to fewer waste and a greener planet. In our researched we are proposing an algorithm and a system for recharging small alkaline batteries which can be reused for many cycles.