This paper describes a system for the simultaneous dynamic control and thermal characterization of the heating of an Ultra Low Power (ULP) micromachined sensor. A Pulse Width Modulated (PWM) powering system has been realized using a microcontroller to characterize the thermal behavior of a device. Objectives of the research were to analyze the relation between the time period and duty cycle of the PWM signal and the operating temperature of such ULP micromachined systems, to observe the thermal time constants of the device during the heating phase and to measure the total thermal conductance. Constant target heater resistance experiments highlighted that an approximately constant heater temperature at regime can only be obtained if the time period of the heating signal is smaller than 50&#x2009;<svg style="vertical-align:-2.29482pt;width:9.6374998px;" id="M1" height="9.6750002" version="1.1" viewBox="0 0 9.6374998 9.6750002" width="9.6374998"  xmlns="http://www.w3.org/2000/svg">
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F. Rastrello

P. Placidi

L. Abbati

A. Scorzoni

E. Cozzani

I. Elmi

S. Zampolli

G. C. Cardinali

Thermal Transient Measurements of an Ultra-Low-Power MOX Sensor

Condition monitoring of heavy electromechanical equipment is commonly accomplished in the industry using vibration analysis. Several techniques, mainly based on capacitive and piezoelectric accelerometers, have been applied for predictive maintenance. However, the negative influence of the electromagnetic interference (EMI) can be a real problem when electrical signals are used to detect and transmit physical parameters in noisy environments such as electric power generator plants with high levels of EMI. Optical fiber sensors are increasingly used because of the nonelectrical nature of signals. In this paper, the most frequently used vibration optical fiber sensors will be reviewed, classifying them by the sensing techniques and measurement principles. The main techniques, intensity modulation, fiber bragg gratings and Fabry-P&#233;rot Interferometry, will be reviewed here.

Yoany Rodr&#237;guez Garc&#237;a

Jes&#250;s M. Corres

Javier Goicoechea

Vibration Detection Using Optical Fiber Sensors

An equilibrium study of <i>Bacillus atrophaeus</i> (<i>B.a</i>) spores on functionalized Single-Wall Carbon Nanotubes (SWCNTs) has been performed in order to characterize the adsorption properties of the spores/nanotubes complex. The carbon nanotubes here investigated were subjected to a two-step purification and functionalization treatment in order to introduce chemical groups on their basal planes. The inclusion of carboxyl functional groups on the nanotubes was corroborated by Raman and infrared spectroscopy. These carboxyl groups appear to enhance the nanotube-<i>B.a.</i> interaction by reacting with the proteinaceous pili appendages present on the spore surface. The adsorption data demonstrate that bacillus spores diffuse faster on functionalized carbon nanotubes than on as-received and purified nanomaterials. Transmission Electron Microscopy also shows that the chemically treated nanotubes resulted in a swollen nano-network which seems to further enhance the bacillus adsorption due to a more extensive spore-nanotube contact area.

P. Cortes

S. Deng

L. Camacho

G. B. Smith

The Adsorption Properties of <i>Bacillus atrophaeus</i> Spore on Functionalized Carbon Nanotubes

We present a new system for acquiring simultaneously breathing rate and kinetic activity over a period of twenty-four hours. The system is based on a couple of sensors, which are very light, absolutely noninvasive, and compatible with everyday life. 
The proposed breathing sensor is cheap and uses a conductive rubber as active material. An analog signal representing the breathing rate is obtained from the sensor&#39;s signal, breath by breath, without any averaging or filtering. The kinetic activity sensor is based on a tiny accelerometer whose signal is averaged and filtered, so that both sensors have voltage compatible with a slow data logging.

Roberto Marani

Gennaro Gelao

Anna Gina Perri

A New System for Continuous Monitoring of Breathing and Kinetic Activity

Spectral fingerprinting of chemical indicators, using computer screens as light sources and web cameras as imaging detectors, is an emerging approach for chemical sensing with the potential to coexist in common consumer electronic devices.
The migration of this technique to mobile phones is key to extend this sensing approach to the most ubiquitous and familiar type of instrumentation. Here, we investigate the feasibility and performance of spectral fingerprinting on reference samples using a standard mobile phone as a complete measuring platform, where the screen provides controlled illumination while the front camera is the imaging detector. Key elements for the execution of such experiments are the software design, the definition of the sample layout, the type of alignment between the phone and the sample, and the influence of ambient illumination. This paper demonstrates the feasibility of reflectance fingerprinting on standard mobile phones and identify the operating conditions of the key parameters that produce an adequate evaluation performance.

Zafar Iqbal

Daniel Filippini

Spectral Fingerprinting on a Standard Mobile Phone

The objective of this paper is to compare two gyrocompass' schemes for the detection of Earth's true north. These schemes are refered to as dynamic and  static methods. We present a model to characterize the sensitivity of each model as a function of the output signal of the sensor element. We use a fiber optic gyroscope (FOG) as the sensor element.

G. Eduardo Sandoval-Romero

Víctor Argueta-Díaz

A Simple Theoretical Comparison between Two Basic Schemes in Function of the Earth's North Pole Detection: The Static Method

The useful application of optical pulse correlation sensor for wide region quasidistributed fiber strain measurement is investigated. Using region separation techniques of wavelength multiplexing with FBGs and time multiplexing with intensity partial reflectors, the sensor measures the correlations between reference pulses and monitoring pulses from several cascadable selected sensing regions. This novel sensing system can select the regions and obtain the distributed strain information in any desired sensing region.

Xunjian Xu

Antonio Bueno

Koji Nonaka

Salvador Sales

Fiber Strain Measurement for Wide Region Quasidistributed Sensing by Optical Correlation Sensor with Region Separation Techniques

Results are reported for thermophoretic deposition of soot particles on resistivity sensors as a monitoring technique for diesel exhaust particles with the potential of improved detection limit and sensitivity. Soot with similar characteristics as from diesel exhausts was generated by a propane flame and diluted in stages. The soot in a gas flow at 240&#x2013;270<svg     style="vertical-align:-0.20473pt;width:16.4625px;" id="M1" height="13.1875" version="1.1" viewBox="0 0 16.4625 13.1875" width="16.4625"  xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg">
	
		
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</svg> was collected on an interdigitated electrode structure held at a considerably lower temperature, 105&#x2013;125<svg     style="vertical-align:-0.20473pt;width:16.4625px;" id="M2" height="13.1875" version="1.1" viewBox="0 0 16.4625 13.1875" width="16.4625"  xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg">
	
		
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</svg>. The time delay for reaching measurable resistance values, the subsequent rate, and magnitude of resistance decrease were a function of the distance between the fingers in the electrodes and the degree of dilution of the soot containing flow. Soot deposition and subsequent removal by heating the sensor support was also performed in a real diesel exhaust. Good similarities between the behavior in our laboratory system and the real diesel exhaust were noticed.

Doina Lutic

Joakim Pagels

Robert Bjorklund

Peter Josza

Jacobus H. Visser

Ann W. Grant

Mats L. Johansson

Jaska Paaso

Per-Erik Fägerman

Mehri Sanati

Anita Lloyd Spetz

Detection of Soot Using a Resistivity Sensor Device Employing Thermophoretic Particle Deposition

We present experimental results on the release of MEMS devices manufactured using the standard CMOS interconnection metal layers as structural elements and the insulating silicon dioxide as sacrificial layers. Experiments compare the release results of four different etching agents in a CMOS technology (hydrofluoric acid, ammonium fluoride, a mixture of acetic acid and ammonium fluoride, and hydrogen fluoride), describe various phenomena found during
the etching process, and show the release results of multilayer structures.

Daniel Fernández

Jordi Ricart

Jordi Madrenas

Experiments on the Release of CMOS-Micromachined Metal Layers

Radio Frequency Identification (RFID) and wireless sensor networks are wireless technologies that rapidly emerge and show great potential. Combining RFID and wireless sensor networks provides a cost-efficient way to expand the RFID system&#39;s range and to enable an RFID system in areas without a network infrastructure. These two technologies are employed to build a wireless localization system in a children&#39;s theme park. The main purpose of this child localization system is to track and locate children within a certain range near some landmarks in the park. The design experience in this project can be exported to other applications such as object tracking and surveillance.

Chao Chen

Design of a Child Localization System on RFID and Wireless Sensor Networks

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<p><em>Journal of Sensors</em> publishes research focused on all aspects of sensors, from their theory and design, to the applications of complete sensing devices.</p>


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<p>Chief Editor, Professor Harith Ahmad, is currently the director of the Photonics Research Center, University of Malaya, Malaysia. His current research is in the exploration of various 2D and 3D nanomaterials for optoelectronics applications.</p>


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Journal of Sensors - Table of contents 2010

title

Journal of Sensors publishes research focused on all aspects of sensors, from their theory and design, to the applications of complete sensing devices.

Journal of Sensors