Milos Zivanov

Wearable Low-Cost System for Human Joint Movements Monitoring Based on Fiber-Optic Curvature Sensor

In this paper, a measurement system for human joint movements monitoring based on a simple and low-cost intensity modulated fiber-optic curvature sensor is presented. The implemented curvature sensor is made up of a plastic optical fiber, which is optimized for small curvature measurements, and has a high sensitivity in a wide measuring range. The sensor sensitivity and resolution, in the measurement range, are 20 mV/° and 1°, respectively. The fabrication process of proposed curvature sensor is also given. The implemented sensor is wearable, noninvasive, nonintrusive, and completely harmless. In this paper, the characteristics of the sensor measured in laboratory conditions as well as measurements of the human knee joint movements are given. Wireless electronics based on ZigBee are also presented. Therefore, the sensor has the possibility of wireless measurement. The main advantages of this sensor are simplicity, lightness, and flexibility. This sensor is also electrically safe and immune to electromagnetic interference. The application, which provides a possibility of remote human joints monitoring over the internet is implemented in the LabVIEW software package.

Miniature low cost electrochemical sensor module for measurement of gas concentration

This paper describes miniature low cost sensor module for measurement of gas concentration. The aim of this paper is to explain how to make a miniature module with low power consumption and low cost, which can be used for many types of electrochemical gas sensors without major hardware changes. Device is based on AVR ATmega8 microcontroller. As signal processing circuit a specialized integrated circuit LMP91000 configurable via I2C interface is used. All parameters are saved in EEPROM memory. For communication with master device RS-485 interface is used. In application, after power up, sensor device reads parameters from memory and configure the circuit for signal processing, than the sensor is ready to sends data upon master device request. Master device can change any parameter at any time. The designed sensor module costs less than 10 Euros and consumption less than 4 mA, which is in the idle mode is reduced to about 1mA.

Application of GPRS modules in data acquisition and control of devices for air quality monitoring

This paper describes a modern GPRS based system for air pollution monitoring. Due to the widespread of the mobile telephony, currently it is possible to use GPRS modules for wireless data acquisition and control. At the moment, there are a lot of available solutions with usage of GPRS modems and some of them are mentioned in this paper as reference to our design. Explanations of how to use GPRS modem with common problems and solution are given. Designed prototype system consists of Telit GM862 GPRS modem, dsPIC30F4013 microcontroller and set of metal-semiconductor gas sensors with accompanying processing electronic. Integration of microcontroller inside sensing process allows automatic monitoring and support for management of the peripherals units. This system measures concentrations of gases such as CO, CO2, NH3, CH4 and H2S. For gas sensor compensation, sensors for humidity, pressure and temperature are installed.

An intensiometric contactless vibration sensor with bundle optical fiber for real time vibration monitoring

In this paper a low-cost fiber-optic intensity based vibration sensor is presented. As sensing element a bundle optical fiber was used. The sensor is based on changes of the reflected light intensity in bundle fiber which is placed near the vibrating element. As the vibrating element loudspeaker cone was used. The sensor was tested in the range of frequencies from 10 Hz to 1 kHz. The minimum detectable amplitude of vibration achieved is 1 μm. An application for real time vibration monitoring in LabVIEW software package was developed. The advantages of the proposed sensor are its simplicity, low-cost, immunity to electromagnetic interference, and the possibility of distributed and long term vibration monitoring over a single optical fiber link.

Desing of Multiphase Boost Converter for Hybrid Fuel Cell/Battery Power Sources

Alternative energy sources are becoming less and less “alternative”. Recent decade has been underlined with worldwide efforts in finding suitable long term alternatives to the carbon based energy sources. There is a multitude of very compelling reasons for investing extra effort – limited supply of natural resources, environmental, geopolitical and even economical reasons. Sun, wind and oceans are all being harnessed to provide stable and reliable energy. That energy is converted for immediate use or for storage in supercapacitors, chemical energy sources or as a derived chemicals (Hydrogen is produced, for instance). Next link in the alternative energy chain is efficient use. New supercapacitors are being developed and there are many different battery types already available on the market, each with its own unique application that optimizes efficiency of chemical conversion and number of charge/discharge cycles with minimum of capacity loss. Fuel cells are being used to efficiently reclaim energy stored in Hydrogen. The process has been well known for decades and is being used in power generation industry in high power systems. As the technology advanced, lower power applications were found – chemical industry was a big benefactor: most of the exhaust gasses could be reclaimed and have Hydrogen extracted in a simple, cost effective manner, ensuring a free energy supply once initial investment in fuel cells and regenerators has been made. Development of new materials helped further reduce costs and increase efficiency, and even low power fuel cells are now widely available. Even though there are still many new and exciting ongoing developments, the technology is now considered mature and ready for prime time. Fuel cells have a good history in many applications (chemical industry, power generation, transportation) and is considered a serious contender in many other industries. In some of these industries fuel cells will gain faster acceptance than in others. Material handling industry is among those where benefits of fuel cells can be easily documented and increased cost of initial implementation justified. A fuel cell based system that replaces standard forklift battery pack has many advantages, such as: fast refueling, longer run time between refueling, longer life of the energy source and low maintenance requirements.

White-Light Interferometric Sensor for Rough Surface Height Distribution Measurement

A very simple white-light interferometric sensing system for rough surface (RS) height distribution measurement is presented. A simple mathematical analysis is given, where as a final result, the probability density function (PDF) of the RS heights is obtained. The PDF has been found to be proportional to the inverse Fourier transform of the ratio of two optical power spectrums, the ¿high frequency¿ part of the channeled spectrum at the interferometer output and the white-light source spectrum, respectively. An experimental setup, based on a very simple fiber-optic interferometeric sensing unit, has been built in order to verify the result of the given mathematical model. A relatively good matching between the surface roughness of the known material and the measurement result is obtained.

Energy harvesting wireless sensor node for monitoring of surface water

Monitoring of surface water areas before, during and after the flood is important to collect useful information for future risk assessment and for the purpose of learning about future preventive measures. This paper describes the development of the wireless sensor network (WSN) node capable of collecting water level measurement data on remote locations that are covered by surface waters, either by flooding or seasonal environmental impacts. Our main goal was to create a flexible, easy-to-deploy and easy-to-maintain, adaptable, low-cost and low power WSN node for monitoring of water level. Measuring node is based on the ultra low power components, with the most important MSP430 series microcontroller and radio frequency (RF) module based on nRFf24l01+ integrated circuit. Each node contains energy harvesting subsystem and supercapacitor for energy storage. Water level measurement is performed by a separate module, which is based on PIC12F1822 microcontroller that supports small capacitance measurements. Water level measurement results for different situations were collected, analyzed and graphically presented.

Experimental and simulation analysis of fiber-optic refractive index sensor based on numerical aperture

In this paper a very simple refractive index sensor made up of plastic optical fibers is presented. Produced fiber-optic sensor is based on intensity change due to refractive index change. The proposed sensor has linear characteristic in the range of refractive indices of tested liquids (1.33-1.47). The results obtained by simulation are well consistent with the results obtained by measurements and analytically. The proposed sensor is characterized with simple and low-cost design, and high immunity to electromagnetic interference.

Interleaved boost converter for hybrid fuel cell systems

Fuel cells are gaining popularity in wide range of industries. This paper outlines critical steps in designing power regulators for hybrid fuel cell systems. Such systems are gaining acceptance in industrial vehicles, forklifts, etc. Harsh operating environments (temperature and peak load demand) along with price pressures require optimized design for peak performance and easier market penetration. 5kW converter described in the paper has met or exceeded all of the requirements with comfortable margin.

Remote monitoring of water salinity by using side-polished fiber-optic U-shaped sensor

In this paper, a remote water salinity measurement system based on a simple and low-cost intensity based side-polished fiber-optic U-shaped sensor is presented. The sensor system utilizes a side-polished U-shaped configuration in order to maximize the sensitivity and expand the measurement range. The implemented salinity sensor is made of a multimode plastic optical fiber, and sensor determines the salinity by measuring the refractive index. Measurement resolution and uncertainty of proposed salinity sensor are 0.001 and 0.002, respectively. Wireless electronics based on ZigBee protocol is also implemented. Therefore, the sensor has the possibility of wireless measurements. The main advantages of this sensor are simplicity, lightness and flexibility. This sensor is also electrically safe and immune to electromagnetic interferences. In LabVIEW software package client and server applications are implemented, which gives a possibility of remote monitoring of water salinity over the internet.