Telemetry field has grown exponentially in recent years. Several applications in medicine, military and automotive industries have been reported recently in literature. This work presents a simple, easy to implement digital remote tachometer based on a Hall effect sensor. A correct characterization is crucial to properly handle, analyze and interpret signals from any kind of sensor, however, here is presented the whole telemetric system characterization, including sensing stage, wireless transmission and reception under IEEE 802.15.4 standard, data analysis and display through a graphical user interface developed on LabView software. A DC motor is placed remotely, where, using a Hall effect sensor and the adequate signal conditioning, a pulse train proportional to the motor speed is sent to a microcontroller to manage signals and compute speeds before wireless transmission. Once received, data is analyzed, displayed and ready to be used as a control variable. Both simulation and experimental results under diverse conditions of speed, transmission distances and computation parameters are presented to clearly describe the process of characterization and system validation. Promising results have been achieved and is expected to growth this project to different physical variables oriented to monitor and control a formula SAE Electric automobile.

The proper design of a product life cycle may contribute both to the optimization of primary raw material uses and to the reduction of waste environmental impacts. Recycling may enter the life cycle of materials in the contexts of production of secondary raw materials and in the reduction of waste extensive disposal in landfills. Tradition plants for plastic separation in homogeneous products employ material physical properties (for instance density). Due to the variability of the properties of various polymers in reduced intervals, the output quality may not be adequate enough. Sensing technologies based on hyperspectral imaging enter this framework being suitable to separate materials and increase the quality of recycled products, which have to comply with specific standards determined by industrial applications. This paper presents the results of the characterization of two different typologies of plastics, namely PET and PVC, in some phases of their life cycle (raw materials, waste and regenerate conditions) to show the contribution of hyperspectral methods in the field of material recycling. This is accomplished via near-infrared (900-1700 nm) reflectance spectra acquired with a linear spectrometer. Though reflectance values depend on many factors such as the characteristics and the thickness of the materials, the lighting conditions, the characteristics of the instrumentation used, and the background, characteristic spectral profiles of PET and PVC samples have been obtained allowing a robust statistical analysis to be developed. Wavelengths 1200 nm and 1650 nm result to be the most suitable for sample classification.

The conventional photolithography of crystalline silicon techniques is limited to two-dimensional and structure scaling. This can be overcome by using laser micromachine, a technique capable of producing three-dimensional structure and simultaneously avoiding the needs for photomasks. In this paper, we report on the use of RapidX-250 excimer laser micromachine with 248 nm KrF to create in-time mask design and assisting in the fabrication of micro-cantilever structure. Three parameters of the laser micromachine used to aid the fabrication of the micro-cantilever have been investigated; namely the pulse rate (i.e. number of laser pulses per second), laser energy and laser beam size. Preliminary results show that the 35 um beam size and 15 mJ energy level is the most effective parameter to structure the desired pattern. The parallel lines spacing of the structure can be reached up to 10 um while cutting, holes drilling and structuring the cantilever using the laser beam can be accomplished to as low as 50 um in dimension.

In this paper we propose a simple, reusable and non-intrusive approach for programming the Zolertia-Z1 mote through the JTAG-port.  Programming the Zolertia-Z1 mote is generally achieved by using the Contiki Boot Script Loader and a USB cable. However, complications arise when building programs which exceed the 64kB-boundary of program memory. Special care must be taken in order to fully utilize the 92kB of available memory. At one hand, a 20 bit compiler is needed to support the complete available memory. At the other hand, a JTAG connection must then be used in order to flash the program onto the MSP430-microcontroller of the Zolertia-Z1 mote. Solutions exist in the aim of facilitating the JTAG-programming. However, these solutions are generally not reliable or need an intrusive approach, or are prohibitively expensive. Therefore, we propose a non-intrusive, reusable and reliable solution based on pogo pins. The Pogo-Pin JTAG Programmer Box consists out of an adapter board and the box itself. The adapter board can be used separately from the box for one-time flashing. Using both at the same time ensures reliable consecutive reprogramming cycles of the Zolertia-Z1 mote.

Constructed wetlands are an environmentally considerate means of water purification. Automating parameters such as heating and aeration may extend the lifetime of constructed wetlands and allow for superior waste-water treatment. One critical parameter to monitor in a wetland system is clogging of pores within the gravel matrix, as this limits the viable lifetime of the system. It has previously been observed in a laboratory setting that magnetic resonance (MR) relaxation measurements, T₁ and T₂^eff, can be used to characterise the clogging state. Various open-geometry MR sensors have been constructed using permanent neodymium magnets with the view of long-term embedding as part of the EU FP7 project ARBI (Automated Reed Bed Installations). The ultimate aim is to monitor clogging levels over the lifetime of the reed bed using MR techniques. One issue with taking various MR measurements over such an extreme time scale, in this case years, is that temperature fluctuations will significantly alter the magnetic field strength produced by the sensors constituent magnets. While the RF transmit-receive circuit has been built so that MR can still be conducted at a range of frequencies without altering the tuning or matching of the circuit, this will result in poor RF excitation if the magnetic field strength shifts significantly. This work investigates the effect that temperature has on the a MR sensor intended for embedding, to determine whether received signal intensity is compromised significantly at large temperature changes.

Collecting the data and forwarding it to its destination is an important function of a sensor network. For many applications, it is also very important to include the location information to the collected data. Localization techniques in wireless sensor networks (WSNs), which is a way of determining the sensor node locations can be utilized for obtaining such information. In this paper, we present an artificial feed-forward neural network based approach for node localization using the RSSI values of the anchor node beacons. The method was applied in a 5 x 4 m indoor environment with beacons installed at each of the corners. Five different training algorithms have been evaluated to obtain the training algorithm that gives the best results for this scenario. The multi-layer Perceptron (MLP) neural network has been obtained using the Matlab software and implemented using the Arduino programming language on the mobile node to evaluate its performance in real time environment. An average 2D localization error of 30 cm is obtained using a 12-12-2 feed-forward neural network structure. The method proposed can be used to implement a trained neural network using other programming languages on other platforms.

Smartphones equipped with various sensors provide sufficient sensor data and computation power to enable daily activity detection for applications such as u-healthcare, elderly monitoring, sports coaching and entertainment. Instead of applying multiple sensor devices, as observed in many previous investigations, this work proposes the use of a smartphone with its built-in accelerometer as an unobtrusive sensor device for real time activity recognition of basic daily activities. The proposal is tested experimentally through evaluations on real data collected from 50 participants. A prototype application is developed to demonstrate and evaluate the selected classification methods for the designated recognition tasks. The results indicates that the J48 classifier using a window size of 512 samples with 50% overlapping obtained the highest accuracy (i.e., up to 96.02%). To measure the actual classification accuracy, a 5x10-fold cross validation with different random seeds was performed on the dataset using WEKA. Finally, to determine whether a classifier is superior to another, 5x2 fold cross validation along with a paired t-test was subsequently performed on the results using J48 as the baseline scheme with the other classification algorithms being compared to it. A value of p<0.05 was considered statistically significant.

Novel type of sensor, whose purpose is to observe skin tissue regeneration, concentration of micro particles of human fluids and etc. by measuring changes of diffraction efficiencies, is being created. The main part of sensor is diffraction grating, produced by the method of hot imprint. Therefore paper is dedicated for analysis and comparison of the quality of microstructures, created with and without high frequency excitation. Three types of measurements are performed: measurement of diffraction efficiency, optical microscopy and atomic force microscopy, in order to analyze the quality of replica. New generation vibroactive pad, whose fundament is stack type piezoactuator, is used to generate high frequency longitudinal vibrations. Thus preheated until glass-liquid transition state polymer, is forced to flow and the quality of microstructure is being enhanced. Both microstructures (with and without vibration excitation) are created on the surface of polycarbonate, using the same temperature, pressure and time modes. During the experiment periodic lamellar microstructure, whose period is 4µm is being analyzed. Analysis of diffraction measurements was performed by using laser and photodiode BPW-34. The relative diffraction efficiency of first maxima of nickel mold is 10 %, of microstructure impressed, by using ultrasonic vibration diffraction efficiency is 9.27 % of microstructure, created without vibration excitation is equal to 4.2 %. Optical microscopy is employed in order to obtain images of magnified surface view, thus allowing detect defects like bubbles of residual gas and distortions, while atomic force microscopy is performed in order to find out surface parameters like period, depth, surface roughness and obtain profile view of created microstructure. This research was funded by a grant (No. MIP-026/2014) from the Research Council of Lithuania.

Wireless sensor networks (WSN) have large scope in structural health monitoring (SHM) applications such as monitoring strength of buildings, bridges, tunnels etc. But WSN based SHM need to face many challenges to get the same performance as its counterpart, the wired network. Placement of sensor nodes has an important role in WSN based SHM, as it needs to find a high quality position, so that it satisfies monitoring requirements and WSN challenges like energy efficiency, connectivity, fault tolerance and reliability. Monitoring quality could be obtained by sensor placement using effective independence method (SPEM) by maximizing fisher information matrix (placement quality indicator) which is used for sensor placement in Civil engineering structures, but it does not guarantee any WSN requirements. This paper therefore focuses on an energy efficient sensor placement method by improving SPEM, so that it improves the life time of sensor nodes or it minimizes the maximum energy used by the sensor for transmitting data to the base station and also ensures monitoring quality. The performance of the proposed placement method has been tested by MATLAB simulations and the result is compared with the sensor placement using effective independence method. This method obtains almost the same placement quality as that provided by using effective independence method, but with improvement in system life time.

In this paper, we experimentally analyze the sensitivity of piezoelectric transducers for damage detection in structural health monitoring (SHM) systems based on the electromechanical impedance (EMI) method, which has been reported as one of the most promising methods for non-destructive detection of damage. The sensitivity of the transducers for damage detection was assessed by comparing the electrical impedance signatures in an appropriate frequency range and using damage indices. Two damage indices commonly used in the literature were used in this study: the root mean square deviation (RMSD), which is based on the Euclidean norm, and the correlation coefficient deviation metric (CCDM), which is based on the correlation coefficient. Three types of transducers were evaluated: conventional 5H PZT (lead zirconate titanate) piezoceramics; macro fiber composite (MFC) devices, which have been widely used in recent years due to its high flexibility; and piezoelectric diaphragms, which are commonly known as "buzzers" and have a very low cost. Tests were carried out on aluminum beams and the electrical impedance signatures of the transducers were acquired in a frequency range of 0-550 kHz using a measurement systems based on a personal computer (PC) and a data acquisition (DAQ) device.Structural damage was induced by adding mass (small nuts) in the aluminum beams. The addition of mass changes the mechanical impedance simulating damage, such as crack or corrosion. This procedure has the advantage of not causing permanent damage in the specimens. Thus, the sensitivities of the transducers to detect damage were compared using the damage indices, as previously mentioned. The experimental results conclusively demonstrate that the transducers have different sensitivities for detection of structural damage. In addition, each transducer has an appropriate frequency range for damage detection, which provides high sensitivity. Therefore, the results presented in this paper allow selecting appropriately the piezoelectric transducer according to the application and the suitable frequency range in impedance-based SHM systems.