The present article proposes the realization and implementation of an algorithm for the selective extraction of a spectral component using fast FFT analysis, from the mechanical vibrations recorded with the help of a broadband acoustic sensor. The hardware device consists of a high-resolution data acquisition system and the storage of samples of the useful signal in a memory area. The selective processing of vibrations is done with the help of a FFT algorithm implemented with the help of the ATMEGA microcontroller based on the binary calculation made by weighted amounts with coefficients from the frequency band used. After obtaining the band spectrum of the signal, a software mask will be applied, with a frequency window that will be pre-set by the human user, and only the amplitude of the signal with the desired spectral component will be displayed, thus achieving an intelligent vibration tracking produced by a certain mechanical element or selected functional assembly. The vibration spectrum of a mechanical machine is composed of the sum of the individual spectral components of all interdependent mechanisms. Simulation performed for this paper and results processed using the proposed method lead to the conclusion that a unique harmonic spectrum, obtained using the Fourier transform algorithm with fixed frequency window and limited number of spectral markers, correspond in a unique way to a mechanical state of wear that the microcontroller can store using a variable magnitude vector. Obtaining a buffer of spectral markers stored together with information about the speed and engine rpm allow the development of an original method of fault detection. The article proposes the implementation of the software method with a hard architecture that includes, low pass filter, information processing and display units.
As per the first prototype developed (ultrasonic glove for visual impaired users [1]) a follow-up discussion with a teacher and several students of the Special School for the Visually Impaired in Cluj-Napoca regarding how other other devices may help the life of a visual impaired person. They underlined out the difficulty of matching colours on clothes. This is the reason for this research for available solutions for a colour detecting sensor that can work on the same platform and fulfils the same principals: cost-effective, easy-to-use, portable and low-battery consumption. TCS230 was the best fit for this purpose, an optical colour sensor. Based on the values the sensor reads for red, green and blue, the software decides what colour is displayed in front of the sensor. The prototype that was build can read to the user 11 colours. In order to add more colours in the near future s and also to be able to maintain the prototype effectively, it was decided to use a development board, not to build a smaller scale of it using only the microchip and other components needed.
There is a trend toward increasing the reliability of the power electronics converters used in many applications. Parameters like reliability, efficiency, and power density often are quite opposable, so it is hard to get them all toghether. In this paper, investigation of the load resistor impact upon the overall reliability of a simple DC-DC PoL (Point-of-Load) converter is assessed. SA-TB130PCB-000 evaluation board having embedded synchronous buck converter was selected for testing and measuring MTBF for such a converter. Thermal scanning in infrared was performed in order to obtain the component capsule's temperature which is needed in stress factor calculation. Calculation follows the data provided by MIL-HDBK-217F rev.2 well known and accepted reliability standard.
As an environmentally compatible device, combining low costs, transparency of the entire Photosynthetic Active Radiation (PAR) domain, and an optimal efficiency of the solar cell for the elimination of any energy provided by the conventional sources, dye-sensitized solar cells (DSSCs) are proposed as the most promising candidates for a wavelength-selective photovoltaic greenhouse. Here, we report the influence of temperature and a small concentration of water in the organic electrolyte on the photocurrent density–photovoltage (J–V) characteristics of UV dye-sensitized solar cells. Our results have highlighted that using a special architecture of the photoanode, up to 60 °C, no degradation effect of 10 % water on the photovoltaic performance of DSSC was observed. On the contrary, a small concentration of water has a beneficial effect on the thermal stability of the DSSC confirming the attractive premises for future implementation of DSSCs in the roof of the greenhouse and the long-term stability in outdoor conditions.
This paper presents a successful attempt to create an innovative way of monitoring the air particles in a room. The sensor relies on two basic physics principles: the Tyndall effect and the Venturi effect. The work done so far consists in designing and modelling, 3D printing and testing the aforementioned method. The model proved to be feasible for both quantitative and qualitative air particle measurements, not knowing only how polluted a mass of air is, but also the nature of the pollutant.
