By Topic

Sensors Journal, IEEE

Issue 6 • Date June 2010

Filter Results

Displaying Results 1 - 25 of 29
  • [Front cover]

    Page(s): C1
    Save to Project icon | Request Permissions | PDF file iconPDF (140 KB)  
    Freely Available from IEEE
  • IEEE Sensors Journal publication information

    Page(s): C2
    Save to Project icon | Request Permissions | PDF file iconPDF (36 KB)  
    Freely Available from IEEE
  • Table of contents

    Page(s): 1027 - 1028
    Save to Project icon | Request Permissions | PDF file iconPDF (44 KB)  
    Freely Available from IEEE
  • Autonomous Light Control by Wireless Sensor and Actuator Networks

    Page(s): 1029 - 1041
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2537 KB) |  | HTML iconHTML  

    Recently, wireless sensor and actuator networks (WSANs) have been widely discussed in many applications. In this paper, we propose an autonomous light control system based on the feedback from light sensors carried by users. Our design focuses on meeting users' preferences and energy efficiency. Both whole and local lighting devices are considered. Users' preferences may depend on their activities and profiles and two requirement models are considered: binary satisfaction and continuous satisfaction models. For controlling whole lighting devices, two decision algorithms are proposed. For controlling local lighting devices, a surface-tracking scheme is proposed. Our solutions are autonomous because, as opposed to existing solutions, they can dynamically adapt to environment changes and do not need to track users' current locations. Simulations and prototyping results are presented to verify the effectiveness of our designs. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • FBAR-CMOS Oscillator Array for Mass-Sensing Applications

    Page(s): 1042 - 1047
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1265 KB) |  | HTML iconHTML  

    Thin-film bulk acoustic resonators (FBAR) are an effective platform for sensitive biological and chemical detection, where their high operating frequencies make them many times more sensitive than a quartz crystal microbalance. Here, we present a monolithic, solidly mounted FBAR oscillator array on CMOS for mass-sensing applications. Through monolithic integration with CMOS drive circuitry, we aim to overcome the spatial and parasitic load limitations of externally coupled resonators to build dense sensor arrays without specialized fabrication techniques. The sensors in this work are constructed in a 6 × 4 array atop a 0.18 ¿m CMOS active substrate, and mass sensitivity comparable to off-chip FBAR sensors is demonstrated. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Passive Wireless Monitoring of Wafer Cleanliness During Rinsing of Semiconductor Wafers

    Page(s): 1048 - 1055
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (998 KB) |  | HTML iconHTML  

    Semiconductor facilities consume large amounts of water, most of which is used for rinsing of wafers during cleaning steps. To optimize water use, real-time and in situ monitoring of wafer cleanliness during rinsing is necessary. Yet no prior art is real-time and in situ. In this paper, we present a passive wireless sensing system capable of measuring the residual contamination on the wafers in real-time and in situ. The wireless system consists of a micromachined Electro-Chemical Residue Sensor (ECRS) and wireless transponder circuitry based on RFID technology. The ECRS measures the impurities concentration of the water inside micro-features during the rinsing processes. The sensor reading is converted to a frequency by the on-wafer transponder and remotely logged through a wireless link between two coupled inductors, while the transponder captures power from the remote RF signal: a battery-free system. A prototype system was fabricated and its frequency output was characterized by using sodium chloride solution ranging from 190 ppb to 6 ppm. The measured wireless chemical sensor system has a relative uncertainty of less than 1% in the concentration range. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Opacity Sensor Based on Photovoltaic Effect of Ferroelectric PLZT Ceramic With Pt Wire Implant

    Page(s): 1056 - 1060
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (936 KB) |  | HTML iconHTML  

    This work reports the formation of a ferroelectric poled bulk ceramic structure as opacity sensor (OPS) and the improved photovoltaic output of the lead lanthanum zirconate titanate (PLZT) employed. This ceramic was implanted during its fabrication with a platinum wire (Pt-wire) which works as an internal electrode. Photovoltaic current have been measured in PLZT with Pt-wire under chopped LASER beam illumination. This photovoltaic current was measured on the upper face of a sensor in order to obtain a characterization curve. Different thin materials were put on the OPS in order to determine its opacity according to their thickness and viscosity. Opacity is a condition in which a material partially or completely impedes the passage of light beam. The results indicated that the photovoltaic current response was less than 700 pA at 160 mW/cm2 maximum power of illumination; 2-D scans were obtained from fruit tissues, vegetal oils and thin materials at 160 mW/cm2 of illumination in order to get a representation of opacity images. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • An Optical Fiber-Based Curvature Sensor for Endodontic Files Inside a Tooth Root Canal

    Page(s): 1061 - 1065
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1803 KB) |  | HTML iconHTML  

    Fatigue fracture of rotary file inside the root canal of teeth is one of the important equipment failure modes in endodontic treatment. Knowing the curvature of a file in a root canal allows its bending strain and fatigue life to be estimated. This can help to avoid the highly undesirable fracture. Although the canal geometry can be revealed by X-ray radiograph, its 2-D nature may not correctly reflect the true curvature. Moreover, canal curvature is not equivalent to the curvature of an inserted file. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A High-Resolution Silicon-on-Glass Z Axis Gyroscope Operating at Atmospheric Pressure

    Page(s): 1066 - 1074
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1627 KB) |  | HTML iconHTML  

    This paper describes a high-resolution silicon-on-glass z axis gyroscope operating at atmospheric pressure. The mechanical structure is designed in such a way that it exhibits low cross coupling between drive and sense mode of less than 0.5% simulated using finite-element method and 1.35% verified by experimental measurements. Due to a symmetrically designed structure, the specified bandwidth can be maintained despite of fabrication imperfections. The fabrication process flow is based on a combination of silicon on glass bonding and deep reactive ion etching which results in a large proof mass and capacitances. A closed loop self-oscillation drive interface is used to resonate the gyroscope in the drive mode, which reaches steady-state after 150 ms. Using area-varying capacitors, large quality factors of 217 and 97 for drive and sense mode, respectively, were achieved operating at atmospheric pressure. A low drive voltage, with a 1 Vpeak-peak AC drive amplitude and 10 V DC bias was used to excite the drive mode. The measured scale factor was 10.7 mV/°/s in a range of ±300°/s with a R 2-nonlinearity of 0.12%. The noise equivalent angular rate is 0.0015°/s/Hz1/2 (=5.4°/h/Hz1/2) in a 50 Hz bandwidth. The measured SNR was 34 dB at an angular rate input signal with an amplitude of 12.5°/s and a frequency of 10 Hz. Without any active temperature control, zero bias stability of 1°/s was achieved for long-term measurements over six hours and 0.3°/s for short-term measurements over 120 seconds (1-¿). View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Active Temperature Programming for Metal-Oxide Chemoresistors

    Page(s): 1075 - 1082
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (713 KB) |  | HTML iconHTML  

    Modulating the operating temperature of metal-oxide (MOX) chemical sensors gives rise to gas-specific signatures that provide a wealth of analytical information. In most cases, the operating temperature is modulated according to a standard waveform (e.g., ramp, sine wave). A few studies have approached the optimization of temperature profiles systematically, but these optimizations are performed offline and cannot adapt to changes in the environment. Here, we present an ¿active perception¿ strategy based on Partially Observable Markov Decision Processes (POMDP) that allows the temperature program to be optimized in real time, as the sensor reacts to its environment. We characterize the method on a ternary classification problem using a simulated sensor model subjected to additive Gaussian noise, and compare it against two ¿passive¿ approaches, a nai¿ve Bayes classifier and a nearest neighbor classifier. Finally, we validate the method in real time using a Taguchi sensor exposed to three volatile compounds. Our results show that the POMDP outperforms both passive approaches and provides a strategy to balance classification performance and sensing costs. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Open Wireless Sensor Network Telemetry Platform for Mobile Phones

    Page(s): 1083 - 1084
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (95 KB) |  | HTML iconHTML  

    Mobile phones are an underutilized resource for connecting low-power wireless sensor networks (WSNs) to the internet. WSNs typically expend most of their battery power on data transmission. Mobile phones carried by the public could enable a hybrid approach where data makes a low-power short distance hop to phones in the vicinity using Bluetooth or a similar short range protocol, then uses the phones' long distance connectivity to upload to the Internet. Because a large fraction of mobile phones have Bluetooth short-distance radio, this paper describes low-cost hardware for a generic WSN-to-Bluetooth gateway and open-source software that allows a wide subset of mobile phones to download and save WSN data. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A Wireless Embedded Sensor Based on Magnetic Higher Order Harmonic Fields: Application to Liquid Pressure Monitoring

    Page(s): 1085 - 1090
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (633 KB) |  | HTML iconHTML  

    A wireless sensor based on the magnetoelastic, magnetically soft ferromagnetic alloy was constructed for remote measurement of pressure in flowing fluids. The pressure sensor was a rectangular strip of ferromagnetic alloy Fe40Ni38Mo4B18 adhered on a solid polycarbonate substrate and protected by a thin polycarbonate film. Upon excitation of a time-varying magnetic field through an excitation coil, the magnetically soft sensor magnetized and produced higher order harmonic fields, which were detected through a detection coil. Under varying pressures, the sensor's magnetoelastic property caused a change in its magnetization, altering the amplitudes of the higher order harmonic fields. A theoretical model was developed to describe the effect of pressure on the sensor's higher order harmonic fields. Experimental observations showed the second-order harmonic field generated by the pressure sensor was correlated to the surrounding fluid pressure, consistent with the theoretical results. Furthermore, it was demonstrated that the sensor exhibited good repeatability and stability with minimal drift. Sensors with smaller dimensions were shown to have greater sensitivity but lower pressure range as compared to their larger counterparts. Since the sensor signal was also dependent on the location of the sensor with respect to the excitation/detection coil, a calibration algorithm was developed to eliminate signal variations due to the changing sensor location. Because of its wireless and passive nature, this sensor is useful for continuous and long-term monitoring of pressure at inaccessible areas. For example, sensors with these capabilities are suitable to be used in biomedical applications where permanent implantation and long-term monitoring are needed. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Design and Experimental Study of a CNT Sensor for Measuring Alcohol Content With Short Response Delay

    Page(s): 1091 - 1097
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (604 KB) |  | HTML iconHTML  

    Excessive alcohol content in human body can impair ability, degrade performance, and result in serious diseases. Nonintrusive and real-time sensing of alcohol content in human body is thus an important research topic. This paper describes the development of a novel carbon nanotube (CNT)-based alcohol sensor with a particular focus on the response delay problem presented in CNT based sensors. Three types of the CNT-based sensor were designed and tested to examine. The result concluded: 1) single-walled CNT is promising as the alcohol sensor with their good linearity and sensitivity and 2) single-walled CNTs with metal pads or without metal pads can both perform well. The second conclusion further implies a great promise of single-walled carbon nanotube with metal pads as alcohol sensors, as the metal pad is an important element to facilitate data reading. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Low-Cost Calibration Techniques for Smart Temperature Sensors

    Page(s): 1098 - 1105
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1011 KB) |  | HTML iconHTML  

    Smart temperature sensors generally need to be trimmed to obtain measurement errors below ±2°C. The associated temperature calibration procedure is time consuming and therefore costly. This paper presents two, much faster, voltage calibration techniques. Both make use of the fact that a voltage proportional to absolute temperature (PTAT) can be accurately generated on chip. By measuring this voltage, the sensor's actual temperature can be determined, whereupon the sensor can be trimmed to correct for its dominant source of error: spread in the on-chip voltage reference. The first calibration technique consists of measuring the (small) PTAT voltage directly, while the second, more robust alternative does so indirectly, by using an external reference voltage and the on-chip ADC. Experimental results from a prototype fabricated in 0.7 ¿m CMOS technology show that after calibration and trimming, these two techniques result in measurement errors (±3¿) of ±0.15°C and ±0.25°C, respectively, in a range from -55°C to 125°C. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Near-IR Sparse Detector Sensor for Intelligent Electronic Fence Applications

    Page(s): 1106 - 1107
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (216 KB) |  | HTML iconHTML  

    A proof-of-concept, active near-IR sensor coupled with a classification algorithm that uses the Mahalanobis distance has been shown to be a feasible approach for discriminating among humans, animals, and vehicles for intelligent electronic fence applications. Analysis shows that only a sparse vertical array of detectors is required to sense minimal features from moving objects for reliable discrimination. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Advances in Magnetic Field Sensors

    Page(s): 1108 - 1116
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (729 KB) |  | HTML iconHTML  

    The most important milestone in the field of magnetic sensors was when AMR sensors started to replace Hall sensors in many applications where the greater sensitivity of AMRs was an advantage. GMR and SDT sensors finally found applications. We also review the development of miniaturization of fluxgate sensors and refer briefly to SQUIDs, resonant sensors, GMIs, and magnetomechanical sensors. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Optical-Fiber Accelerometer Array: Nano-g Infrasonic Operation in a Passive 100 km Loop

    Page(s): 1117 - 1124
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (692 KB) |  | HTML iconHTML  

    In this paper, an all-optical accelerometer array system is presented, ideally suited for permanent seismic seabed arrays and passive surveillance. A directly measured accelerometer resolution of better than 60 ng/¿Hz (-145 dB/ reg/¿Hz) down to 10 Hz is achieved for all channels in a completely passive 100 km fiber loop. The detection bandwidth is chosen to be from 10 to 300 Hz, with a closed-loop dynamic range of 120 dB. The crosstalk between channels spaced by 100 GHz is better than -64 dB. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • White-Light Interferometric Sensor for Rough Surface Height Distribution Measurement

    Page(s): 1125 - 1132
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (604 KB) |  | HTML iconHTML  

    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. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Force Sensors Based on Screen-Printed Cantilevers

    Page(s): 1133 - 1137
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (431 KB) |  | HTML iconHTML  

    In this paper, the design, the fabrication, and the characterization of glass ceramic screen-printed force sensors are described. They are based on the use of cantilevers with integrated piezoresistors. The choice of the materials constituting the cantilever and the strain gauge, so as the dimensions of the cantilever have been optimized in order to measure forces in mN range. The sensors have been fabricated using the screen-printing technique associated with the sacrificial layer technique to release the freestanding part of the cantilevers. Afterwards, they have been characterized: measurement of sensitivity, reproducibility, and materials properties (Young's modulus and strain gauge factor). The performances of these sensors are compared to the existing silicon, polymer, and ceramic sensors. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Geographic Node-Disjoint Path Routing for Wireless Sensor Networks

    Page(s): 1138 - 1139
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (203 KB) |  | HTML iconHTML  

    One of the challenging issue in wireless sensor networks (WSNs) is efficiently route the multimedia information. In this letter, we propose an efficient geographic routing algorithm for multimedia data transmission such as audio, video, etc., in WSNs. It finds one near to shortest path per iteration and can be performed repeatedly iteration to find more on-demand shortest node-disjoint routing paths. This algorithm achieves high-throughput with low delay that is required for multimedia data transmission over WSNs. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Transversal-Load Sensor by Using Local Pressure on a Chirped Fiber Bragg Grating

    Page(s): 1140 - 1141
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (215 KB) |  | HTML iconHTML  

    A transversal-load sensor based on the local pressure-induced refractive index change in a chirped fiber Bragg grating (CFBG) is proposed. The local pressure induced refractive index change in the touch point can generate a main transmission peak and several subpeaks on the long wavelength side of the reflection band of the CFBG. The difference of the wavelength shifts for the main transmission peak and the first subpeak is used to measure transversal-load with temperature compensation capability. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Low-Power and High-Sensitivity Humidity Sensor Using Fe-Al-Polyaniline Blends

    Page(s): 1142 - 1146
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (937 KB) |  | HTML iconHTML  

    We fabricated a humidity-sensing material, using a solution-based process of Fe-Al-polyaniline (PANI) blends. The characteristics of the developed material were verified by IR, UV-visible (VIS) spectroscopy, and SEM. Based on these observations, the water vapor absorption introduced the resistance change of the PANI blends. In addition, the fabricated sensor was also evaluated as having low power consumption and high sensitivity because of its 108 ¿ intrinsic resistance and exponential response to humidity changes. It also showed good predictability within the examined relative humidity range of 35% to 70%. We also examined the sensor selectivity, reproduction, setup time, and temperature stability. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Temperature Robust Refractive Index Sensor Based on a Photonic Crystal Fiber Interferometer

    Page(s): 1147 - 1148
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (189 KB) |  | HTML iconHTML  

    We present a simple photonic crystal fiber (PCF)-based reflection type interferometer insensitive to temperature for refractive-index measurement. By simply collapsing the airholes at a middle point and forming a reflector at the end of a PCF, the interferometer could be implemented. The PCF sensor showed a low thermal sensitivity even without any compensation process. The feasibility as a refractive-index sensor is demonstrated by presenting the spectral response to liquids having various refractive indexes and to temperature. The implemented sensor showed a good sensitivity of 850 nm/RUI (refractive unit index). View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • PVC Smart Sensing Foil for Advanced Strain Measurements

    Page(s): 1149 - 1155
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1015 KB) |  | HTML iconHTML  

    Monitoring systems can already be found in common applications, from automotive to aeronautics or biomedical. However, the application of these monitoring systems has not yet been a very easy task, especially, at the sensor application step. A smart structure with sensing capabilities would allow to overcome the existing issues in the installation of sensor networks. As the size of this type of systems and the market requirements are significant, an industrial manufacturing process needed to be considered. An integrated solution based in Fiber Bragg Grating sensors embedded in PVC laminates was manufactured by industrial spread-coating process. The resultant structure is a temperature and strain sensitive foil that was characterized in terms of surface structure, optical response and overall performance. The integrated solution behavior had a slope of 0.8 pm by microstrain with a measurement range of 1.2 mm when the fiber was straight in the foil. Different fiber layouts were also tested and defined the minimum curve radius in 10 mm. The foil also presented a dimensional stability above 99%, ensuring the capability to sustain molding process. A mechanical analysis to evaluate the elongation capabilities and optical response was conducted. Three samples with different sensor positioning were subjected to the test. In the end, a sample, with the sensor in a 45° angle regarding the displacement axis, achieved the best compromise between maximum elongation range (25%) and optical response linearity. For the temperature response, a wavelength deviation of 1.7 nm was obtained for a 100°C temperature change. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Measurement of Low Gas Concentrations Using Photonic Bandgap Fiber Cell

    Page(s): 1156 - 1161
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2098 KB) |  | HTML iconHTML  

    In this paper, we present a novel low-loss splice for use between the photonic bandgap fiber (PBGF) and the conventional solid-core fiber to make PBGFs more functional. Furthermore, the hollow-core and the holes in the cladding of PBGF act as gas pipes. Using the proposed splice, a measurement system for low gas concentrations based on the PBGF cell has been developed and implemented. Experiments for measuring ammonia (NH3) gas at the ppm level were performed. The basic peak agreed well with the database of the Pacific Northwest National Laboratory (PNNL), meaning that this method can be used to accurately and effectively measure gas concentration. The constructed gas cells are compact and cost-effective for sensitive, rapid, and continuous measurement of gases. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.

Aims & Scope

The IEEE Sensors Journal is a peer-reviewed, monthly online/print  journal devoted to sensors and sensing phenomena

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Krikor Ozanyan
University of Manchester
Manchester, M13 9PL, U.K.