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Van, den Heever Thomas Stanley. "A zinc oxide nanowire pressure sensor." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/5369.
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Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2010.Thesis presented in partial fulfilment of the requirements for the degree Master of Science in Engineering at the University of Stellenbosch
ENGLISH ABSTRACT: Measurement of pressure with zinc oxide (ZnO) nanowires was investigated. ZnO exhibits the piezoelectric effect, generating a voltage when pressure is applied to the material. This relationship between pressure and output voltage was used to make a pressure sensor. A study of the physical and mathematical working of the piezoelectric effect in ZnO nanowires was done. Simulations were conducted by means of specialised software to test the theory. The simulations gave results as the theory had predicted. ZnO nanowires were grown using various methods. Vapour liquid solid (VLS) was found to be the best method to grow uniform and dense arrays of ZnO nanowires. Statistical methods were employed to obtain the optimal parameters for the growth of ZnO nanowires through the VLS method. After the growth of the ZnO nanowires a pressure sensor was built. The manufacturing of the pressure sensor consisted of different steps. The sensors were tested to verify that they worked as described in theory and as shown in the simulations. The output voltage was lower than the simulated value due to imperfections and losses throughout the system. The output voltage versus applied pressure graphs did coincide with the bulk ZnO materials as well as related products, such as force sensing resistors. The output voltage is too low, but there are various methods by which the output voltage can be increased. These methods are discussed. The finished sensor can be used to continuously monitor pressure on a plane.
AFRIKAANSE OPSOMMING: Die meting van druk deur sink oksied (ZnO) nanodrade was ondersoek. ZnO toon die piëzo-elektriese effek - spanning word gegenereer wanneer druk op die materiaal aangewend word. Hierdie verhouding tussen druk en uitsetspanning is gebruik om ’n druksensor te vervaardig. ’n Studie van die fisiese en wiskundige werking van die piëzo-elektriese effek in ZnO nanodrade is gedoen. Simulasies deur middel van gespesialiseerde sagteware is uitgevoer om die teorie te bevestig. Die simulasies het resultate getoon soos deur die teorie beskryf word. ZnO nanodrade is gegroei deur verskillende metodes. Verdamping vloeistof vastestof (VVV) is as die beste metode gevind om uniforme en digte skikkings van ZnO nanodrade te kry. Statistiese metodes is aangewend om die optimale parameters vir die groei van ZnO nanodrade deur middel van die VVV metode te kry. Na afloop van die groei van die ZnO nanodrade is ’n druksensor vervaardig. Die vervaardigingsproses het uit verskillende stappe bestaan, ten einde die bou van ’n werkende druksensor uit die ZnO nanodrade te realiseer. Die sensors is getoets om te bevestig dat dit werk, soos beskryf deur die teorie en gewys in die simulasies. Die uitsetspanning was laer as wat verwag was as gevolg van onvolmaakthede en verliese in die hele stelsel. Die uitsetspanning teenoor druk grafieke van die sensor het ooreengestem met die van die grootmaat materiale, asook verwante produkte soos druk sensitiewe weerstande. Die uitset spanning is baie laag en daar bestaan verskillende maniere waarop die uitsetspanning verhoog kan word. Hierdie metodes word bespreek.
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Medler, Alison Elizabeth. "A thin monocrystalline diaphragm pressure sensor using silicon-on-insulator technology." Thesis, Middlesex University, 1998. http://eprints.mdx.ac.uk/8109/.
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The sensors market is huge and growing annually, of this a large sector is pressure sensors. With increasing demands on performance there remains a need for ultraminiature, high performance pressure sensors, particularly for medicai applications. To address this a novel capacitive pressure sensor consisting of an array of parallel connected diaphragms has been designed and fabricated from SIMOX substrates. The benefits of this include single crystal silicon diaphragms, small, well controlled dimensions, single sided processing and the opportunity for electronics integration. Theoretical modelling of this structure predicts a high sensitivity and low stress device with opportunities for scaling to suit alternative applications. A novel, process technology was developed to achieve the required structure with the inclusion of procedures to address the specific issues relating to the SIMOX material. The sensor was fully characterised and the results demonstrated high performance compared with similar reported devices. Alternative structures such as cantilevers, bridges and resonators were fabricated as a demonstrative tool to show the feasibility of this technology in a wider field of applications.
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Booth, M. J. "Design and development of a distributed planar pressure sensor utilising electrical impedance tomography." Thesis, Sheffield Hallam University, 2000. http://shura.shu.ac.uk/19369/.
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This thesis describes an investigation into the use of electrical impedance tomography used in conjunction with a flexible conductive sensor for the measurement of distributed pressure. The main application areas are for the constant monitoring of the pressure distribution between a patient and their support surface i.e. beds and wheel chairs, in order to reduce the formation of pressure sores and tactile sensing for robotics. A number of systems have been developed for the monitoring of patients but non-have proved suitable for constant monitoring and these are reviewed. A review of the tactile sensor techniques used in robotic grippers is presented and when the area to be monitored is relatively small (1-2 cm2) the techniques already under development can provide the resolution required. However no technique exists to measure distributed pressure over a large area. A review of both the hardware and reconstruction algorithms used in electrical impedance tomography is presented and the design of the hardware and software developed for the investigation into the sensor design is detailed. As the sensor is such that electrodes are not limited to the periphery both an experimental and computer simulated comparison of three different electrode configurations is described. The three-electrode arrangements investigated are with the electrodes placed at the periphery of both a circular and square boundary, and with electrodes evenly distributed across a square area. The results from the comparisons show that the new distributed electrode arrangement performs significantly better than when the electrodes are confined to the periphery. It also shows that the geometry of the boundary when using peripheral electrodes can also effect the performance of an EIT system. The initially investigated sensor design was based on a conductive polymer sheet and a number of samples were characterised in term of their V/I characteristics and their creep and resistance change due to applied pressure. Only one of the sample tested had a response worth investigating further but the material could not be obtained for larger area tests. Therefore an alternative sensor design was investigated. This novel sensor consisted of a conductive fluid retained beneath a flexible rubber membrane. From electrical impedance tomography images obtained from the experimental evaluation of the new sensor design it is shown that the system can image the pressure distribution across its surface. In addition, the analysis of the unprocessed data from the new sensor shows the system to have a well-defined response with a wide applied pressure range and the construction of the sensor is such that its response could be tailored to the range of pressure to be measured.
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Bergmark, Giesler Linn. "Investigating construction and design parameters of an embroidered resistive pressure sensor." Thesis, Högskolan i Borås, Akademin för textil, teknik och ekonomi, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-26450.
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Electronic textiles, or smart textiles, is a field that is growing due to the opportunities it provides. Textile integrated electronics enables soft, flexible, lightweight electronic devices that enable long term monitoring within the medical field. Pressure sensors is one device within this field that has been researched. A textile integrated pressure sensor enables monitoring of heart rate, muscle activity, posture, gait phases and finger movements. In this project a resistive pressure sensor has been produced using embroidery with the purpose of investigating how construction and design parameters influence the resistance-pressure relationship. The study consisted in different phases where in Phase I parameters such as fabric substrate, stitch length and yarn type was examined. Phase II investigated design parameters like electrode pattern design, sensor shape, trace distance and size. In the design phase a new electrode pattern and sensor shape was tested. Finally in Phase III a sensor matix and sensor chain was constructed in order to evaluate the possibility of obtaining touch location. The findings in this study showed that the shape, size and yarn type had the most distinct influence on the sensor performance in regards to the resistance-pressure relationship. In an additional recovery test the results indicated that both textile substrate and stitch length could influence the ability to recover to its original shape after applying cyclic pressure. It was also found that the new pattern design performed equally to the conventional pattern designs and at the same time reduced material consumption as well as the embroidery time. The sensor matrix and sensor chain could display a change in resistance when applying a weight at each sensing element, implying that touch location could be detected, but would need further development in construction before potential implementation.
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Veedhi, Carisma Catherin, and Vasantha Sai Darahas Yeedi. "Estimation of Altitude : using ultrasoinc and pressure sensors." Thesis, Blekinge Tekniska Högskola, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-19950.
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This paper deals with the estimation of altitude of the drone for which the sensors like ultrasonic, barometric pressure sensors and their characteristics plays a major role. To estimate the altitude of the drone, we used the matlab software with Simulink. apart from the software and hardware description, we discuss several issues regarding the equipment,abilities and performance of the drone.
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Skvorchevsky, A. Y. "ELS capacity control system for axial-piston pumps." Thesis, Національний технічний університет "Харківський політехнічний інститут", 2016. http://repository.kpi.kharkov.ua/handle/KhPI-Press/46920.
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Cordeiro, Juliana Ribeiro. "Síntese e aplicação de polímeros condutores em sensores olfativos." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/46/46135/tde-08112010-084724/.
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Os objetivos do trabalho consistem em síntese e caracterização de três polímeros: poli(2,1,3-benzotiadiazol-4,7-ilenovinileno) (PBTDV), poli(2,1,3-benzotiadiazol-4,7-ilenovinileno-co-2-bromo-5-hexilóxi-p-fenilenovinileno (PBTDV-co-BHPPV) e poli(2-bromo-5-hexilóxi-p-fenilenovinileno) (BHPPV), sendo os dois primeiros inéditos; aplicação de polímeros condutores no desenvolvimento de um nariz eletrônico capaz de identificar madeiras; e aplicação de polímeros condutores em um sensor de pressão. Os polímeros foram preparados de maneira satisfatória via redução catódica de seus precursores tetra-halogenados, que forneceu produtos com rendimentos apreciáveis. Para o projeto do nariz eletrônico que pretende identificar madeiras, dois conjuntos de espécies de madeira foram estudadas: (a) mogno e cedro e (b) imbuia e canela-preta. O nariz eletrônico desenvolvido apresenta um conjunto de quatro sensores de gás, que foram construídos por meio da deposição de finos filmes de polímeros dopados sobre a superfície de eletrodos interdigitados. Esse conjunto de sensores foi desenvolvido com sucesso, sendo capaz de diferenciar as espécies de madeira com taxa de acerto de 100%. Por fim, foi desenvolvido também com sucesso um sensor de gás capaz de atuar como sensor de pressão. Esse dispositivo mostrou-se sensível à variação de pressão, do vácuo a ambiente, e os ensaios apresentaram boa reprodutibilidade. A resposta do sensor, frente à variação de pressão, é produto de interação(ões) entre a camada ativa do polímero utilizado (PHBPE, poli(4\'-hexilóxi-2,5-bifenilenoetileno)) e algum(ns) componente(s) do ar atmosférico ou da atmosfera particular do laboratório. Esse sensor é de fácil fabricação e barato (~ R$ 1,00), sendo possível sua aplicação como sensor para pressões menores do que a ambienteThe syntheses of three polymers via electrochemical reduction of their precursors are described. Two out of the three generated polymers have never been described before. An electronic nose was developed capable of identifying two pairs of wood species: (a) mahogany and cedar and (b) Brazilian walnut and black-cinnamon. The electronic nose consisted of four gas sensors, fabricated by the deposition of thin doped polymer films onto the surface of interdigitated electrodes. The device presented a rate of hits of 100% in 80 assays of identification of the above cited species. Finally, a gas sensor based on a conductive polymer and capable of acting as a pressure sensor was fabricated. The sensor was suitable for measuring air pressures in the range of 100 mmHg to 700 mmHg due to its sensibility to one or more specific compounds present in the air. The device is cheap, easy to fabricate and lasts for several months
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Ernmark, Niklas. "Utveckling av en CAN-adapter i ett sensorsystem för övervakning av däcktryck. : Development of a CAN-adapter in a sensor system for tire pressure monitoring." Thesis, KTH, Data- och elektroteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-215071.
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Den här rapporten beskriver ett examensarbete i elektroteknik på Kungliga tekniska högskolan. Syftet var att skapa en unik systemlösning där ett CAN-adapterkort (Controller Area Network) skulle integreras med ett system för övervakning av däcktryck i tunga fordon. Målet var att presentera mätvärden från ventilsensorer på en persondator. Systemet för övervakning av lufttryck heter J1939 – TPMS och är en färdig produkt. J1939 – TPMS skickar CAN-ramar på en CAN-buss i J1939-format. Dessa ramar ska läsas in av adapterkortet och presenteras på ett terminalprogram på en persondator. Arbetet har bestått av att utreda hur systemet J1939 – TPMS fungerar i detalj. Rollen för protokollet J1939 och dess förhållande till CAN har förklarats. Hur J1939-ramar tolkas och hur mätdata rörande TPMS avkodas har beskrivits i detalj. Principer för hur en CAN-nod fungerar har klargjorts. Baserat på detta har ett CAN-adapterkort konstruerats. Konstruktionen har inneburit komponentval, design av elektronikschema, design av mönsterkort och utveckling av inbyggd programvara. Resultatet blev ett färdigt och fungerande CAN-adapterkort som har testats med J1939 – TPMS. Kraven för projektet uppfylldes. Dock så kommer mer arbete med kortet och systemet behövas för att det ska bli en färdig produkt. Arbetet genomfördes hos Motion Control i Västerås AB i samarbete med Transeco Däckservice.This report describes a degree project at the Royal Institute of Technology. The purpose was to create a unique system solution in which a CAN adapter card (Controller Area Network) was to be integrated with an air pressure monitoring system for heavy duty vehicles. The goal was to present measurement values from valve sensors on a personal computer. The air pressure monitoring system is called J1939 - TPMS and is a finished product. J1939 - TPMS sends CAN-frames to a CAN-bus in J1939 format. These frames are to be read by the adapter card and presented on a terminal program on a personal computer. The job has been to investigate how the J1939 - TPMS system works in detail. The role of the J1939 protocol and its relationship with CAN has been clarified. Also, a detailed description of how J1939 frames are interpreted and how the measuring data TPMS is decoded is done. Principles for how a CAN node works has been clarified. Based on this, a CAN adapter card has been designed. The design has included component selection, design of electronics schema, design of computer cards and development of embedded software. The result was a ready-to-use CAN adapter card tested with J1939-TPMS. Requirements for the project were met. However, more work with the card will be needed to make it a finished product. The work was carried out at Motion Control in Västerås AB in cooperation with Transeco Däckservice (Transeco Tire Service).
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Скворчевський, Олександр Євгенович. "Нове покоління гідравлічних приводів для мобільних машин на основі принципу e-LOAD SENSING (e-LS)." Thesis, Харківський національний автомобільно-дорожній університет, 2019. http://repository.kpi.kharkov.ua/handle/KhPI-Press/41789.
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Ibrahim, Amr. "Remotely interrogated MEMS pressure sensor." Thesis, University of Glasgow, 2012. http://theses.gla.ac.uk/4149/.
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This thesis considers the design and implementation of passive wireless microwave readable pressure sensors on a single chip. Two novel-all passive devices are considered for wireless pressure operation. The first device consists of a tuned circuit operating at 10 GHz fabricated on SiO2 membrane, supported on a silicon wafer. A pressure difference across the membrane causes it to deflect so that a passive resonant circuit detunes. The circuit is remotely interrogated to read off the sensor data. The chip area is 20 mm2 and the membrane area is 2mm2 with thickness of 4 µm. Two on chip passive resonant circuits were investigated: a meandered dipole and a zigzag antenna. Both have a physical length of 4.25 mm. the sensors show a shift in their resonant frequency in response to changing pressure of 10.28-10.27 GHz for the meandered dipole, and 9.61-9.58 GHz for the zigzag antenna. The sensitivities of the meandered dipole and zigzag sensors are 12.5 kHz and 16 kHz mbar, respectively. The second device is a pressure sensor on CMOS chip. The sensing element is capacitor array covering an area of 2 mm2 on a membrane. This sensor is coupled with a dipole antenna operating at 8.77 GHz. The post processing of the CMOS chip is carried out only in three steps, and the sensor on its own shows a sensitivity of 0.47fF/mbar and wireless sensitivity of 27 kHz/mbar. The MIM capacitors on membrane can be used to detune the resonant frequency of an antenna.
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Poopalasingam, Shivani. "Neural network based digital compensation schemes for industrial pressure sensors." Thesis, Coventry University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.387520.
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Ozgeneci, Ercin Mehmet. "Mems Sensor Based Underwater Ahrs(attitude And Heading Reference System) Aided By Compass And Pressure Sensor." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614619/index.pdf.
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Attitude and Heading angles are crucial parameters for navigation. Conventional navigation methods mostly uses IMU and GPS devices to calculate these angles. MEMS technology offers small sized, low cost IMU sensors with moderate performance. However, GPS cannot be used in underwater. Therefore, different aiding sensors are used in underwater vehicles in order to increase the accuracy. As the accuracy of devices increases, the cost of these devices also increases. In this thesis, rather than using GPS and high quality IMU sensors, low cost MEMS IMU sensor is used together with a magnetometer and a pressure sensor as aiding sensors. Considering the IMU error model and motion dynamics, two systems are designed and simulated using real data. The results seem to be satisfactory and using pressure sensor as an aiding sensor improves the attitude angles estimation.
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Ahmad, Jawad. "Screen Printed Large Area Sensors for Pressure Distribution Monitoring in Wheelchairs." Licentiate thesis, Mittuniversitetet, Institutionen för elektronikkonstruktion, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-36139.
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A sedentary lifestyle can induce health related problems including pressure ulcers. Prolonged sitting inadequacies constitute a risk for pressure ulcer to many individuals, in particular people with disabilities and reduced mobility. The measurement of distributed pressure and detection of irregular sitting postures are essential in prevention of the risk of developing pressure ulcers. In this thesis, a screen-printed pressure sensor for a large area is presented, with the objective of measuring the distributed pressure of a seated person in a wheelchair. The conductors and interdigital patterns are printed with silver-based ink. A blend of a non-conductive and a low resistive ink is used for customized resistance for an optimal sensing range of the pressure sensor. The effect of moisture and temperature are realized in an environment chamber. For characterization, other key performance tests such as repeatability, drift and flexibility are carried out. The surface morphology is carried out for structural analysis of printed samples. The sensor data is acquired and processed using an 8-bit ATmega-2560 microcontroller and wirelessly transmitted to a PC for post-processing, storage and analysis. For real-time data presentation of distributed pressure points, a GUI has been developed to display the values obtained from the large area sensor. The detection of four sitting postures; forward leaning, backward leaning, left leaning and right leaning along with a normal sitting posture is attained. An analysis for stretchable printed tracks has been conducted to investigate the changes in electrical resistance using elongation tests, surface morphology and EDS. The optimal curing time and temperature were investigated to manufacture stretchable conductive tracks. In summary, the contributions in this thesis provides an effective approach regarding pressure distribution measurement and recognizing irregular sitting postures for wheelchair users.Vid tidpunkten för framläggningen av avhandlingen var följande delarbete opublicerat: delarbete 3 (accepterat).
At the time of the defence the following paper was unpublished: paper 3 (accepted).
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Emon, Md Omar Faruk. "Ionic Liquid–Based 3D Printed Soft Pressure Sensors and Their Applications." University of Akron / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=akron1593542345792441.
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McCarthy, Tom. "Automatiserad gatubelysning baserad på omgivningens ljusstyrka : Hur ljussensorteknik kan minska energianvändningen för utomhusbelysning." Thesis, KTH, Hälsoinformatik och logistik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-302562.
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Målet med arbetet var att undersöka hur enskilda gatlyktor skulle kunna utrustas med ljussensorteknik för att implementera automatisk dimring med syftet att sänka energianvändningen. Rapporter visar att väg- och gatubelysningen i Sverige stod för 626 GWh år 2016 samt att en stor del av ljuspunkterna fortfarande består av energikrävande högtrycksnatrium. Uppgifter visar även att energisnåla LED-armaturer blir alltmer förekommande som alternativ till högtryckslampor. Målet var att utveckla en prototyp för LED där funktionen bygger på att lysdioderna ska vara släckta när omgivningens ljusstyrka är hög och dynamisk dimras upp när omgivningens ljusstyrka minskar. Arbetet resulterade i en prototyp som fungerar tillfredsställande och efter uppsatta mål. Varje ljussensor läser in ett analogt mätvärde som tolkas av en mikrokontroller som sedan skickar en pulsbreddsmodulerad signal för styrning av lysdiodens belysningsnivå. Generellt visade arbetet att omfattande fortsatta studier behöver göras innan prototypen skulle kunna implementeras i verkligheten. Prototypen behöver även testas och kalibreras i utomhusmiljö med dagsljus.The goal of this thesis was to investigate how individual streetlights could be equipped with light sensor technology to apply an automatic dimmer function with the purpose of reducing energy usage. Studies show that road and streetlights in Sweden accounted for 626 GWh during the year 2016 and that a large portion of the lights still consists of energy demanding high pressure sodium lamps. Reports also show that energy efficient LED is becoming more and more common as an alternative to high pressure lamps. The goal was to develop a prototype for LED lighting with the function to control the LED’s to be off when the surrounding light levels are high and to dynamically increase the output power when the surroundings light level go down. Each light sensor reads an analog value which is interpreted by a micro controller that sends a pulse width modulated signal to control the LED power output. The finished prototype worked satisfactory and according to the set goals of the thesis. Generally, the thesis showed that extensive research is needed before the prototype could be implemented in real life. The prototype also needs to be tested and calibrated in an outdoor environment with day light.
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Dogantimur, Erkan, and Daniel Johnsson. "Analysis of Accuracy for Engine and Gearbox Sensors." Thesis, Uppsala universitet, Institutionen för teknikvetenskaper, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-388346.
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This thesis provides a standardized method to measure accuracy for engine and gearbox sensors. Accuracy is defined by ISO 5725, which states that trueness and precision need to be known to provide a metric for accuracy. However, obtaining and processing the data required for this is not straight forward. In this thesis, a method is presented that consists of two main parts: data acquisition and data analysis. The data acquisition part shows how to connect all of the equipment used and how to sample and store all the raw data from the sensors. The data analysis part shows how to process that raw data into statistical data, such as trueness, repeatability and reproducibility for the sensors. Once repeatability and reproducibility are known, the total precision can be determined. Accuracy can then be obtained by using information from trueness and precision. Besides, this thesis shows that measurement error can be separated into error caused by the sensors and error caused by the measurand. This is useful information, because it can be used to assess which type of error is the greatest, whether or not it can be compensated for, and if it is economically viable to compensate for such error. The results are then shown, where it is possible to gain information about the sensors’ performance from various graphs. Between Hall and inductive sensors, there were no superior winner, since they both have their strengths and weaknesses. The thesis ends by making recommendations on how to compensate for some of the errors, and how to improve upon the method to make it more automatic in the future.
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Majerus, Steve J. "Wireless, Implantable Microsystem for Chronic Bladder Pressure Monitoring." Case Western Reserve University School of Graduate Studies / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=case1397120012.
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Littlejohn, Samuel David. "Electrical properties of graphite nanoparticles in silicone : flexible oscillators and electromechanical sensing." Thesis, University of Bath, 2013. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.600642.
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This thesis reports the discovery of a wide negative di↵erential resistance (NDR) region in a graphite-silicone composite that was utilized to create a strain-tuned flexible oscillator. Encoding the strain into frequency mimics the behavior of mechanoreceptor neurons in the skin and demonstrates a flexible and electronically active material suitable for state of the art bio-electronic applications. The NDR was investigated over a range of composite filling fractions and temperatures; alongside theoretical modelling to calculate the tunneling current through a graphite-silicone barrier. This led to the understanding that the NDR is the result of a semi-metal to insulator transition of embedded graphene bilayers within the graphite nanoparticles. The transition, brought about by a transverse bias across specifically orientated particles, opens a partial band-gap at the Fermi level of the bilayer. NDR in a flexible material has not been observed before and has potential for creating a flexible active device. The electromechanical properties of the composite were considered through a bend induced bilayer strain. The piezoresistance was found to be dominated by transient resistance spiking from the breaking of conduction lines, which then reform according to the viscoelasticity of the polymer matrix. The resistance spiking was embraced as a novel method for sensitive di↵erential pressure detection, used in the development of two applications. Firstly, it was employed for the detection of ultrasound waves and found to have an acoustic pressure detection threshold as low as 48 Pa. A commensurability was observed between the composite width and ultrasound wavelength which was shown to be consistent with the formation of standing waves, described by Bragg’s law. Secondly, a differential pressure array of 64 composite pixels was fabricated and demonstrated to image pressures under 3.8 kPa at a resolution of 10 dpi. The NDR active region was incorporated into an LC circuit where it was demonstrated to sustain oscillations of up to 12.5 kHz. The composite was then strained and an intrinsic frequency was observed which had a linear dependence on the strain with a frequency shift of 84 Hz / % strain. Lastly the composite was used in a strain-tuned amplifier circuit and shown to provide a gain of up to 4.5. This thesis provided the groundwork for a completely flexible electronically active device for futuristic bio-electronic skins with resolutions and sensitivities rivalling those of human tactile sensing.
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Söder, Peter. "Inventering av olika mätare för Stuguns vattenkraftverk." Thesis, Mittuniversitetet, Avdelningen för elektronikkonstruktion, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-31402.
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Det finns många sensormetoder för vattennivåmätning ute på marknaden idag. Målet för forskningsstudien är att presentera och jämföra några av de mätningsmetoder som finns på marknaden för nivåmätning. I studien jämförs modellerna för trycksensorer, flytsensorer, ultraljudssensor och elektromagnetisk sensor för att sedan se vilken sensor som passar bäst för just mätningar av vattennivåer. Genom, datainsamlingen från sök motorerna Google scholar och Mittuniversitetets egen databas Primo har fakta samlats. Informationen har sedan bearbetas och jämförts mot behoven från Vattenfall som ska göra tre sensorbyten på vattenkraftverket i Stugun. Resultatet av studien visade slutsatsen att utifrån kravspecifikationerna Vattenfall gav så var en trycksensor det bästa alternativet för Stugun. Studien gjorde så att Vattenfall köpte in tre stycken Waterpilot FMX21, 22 mm som sedan sattes på plats och kalibrerades.There are many sensor methods for water level measurement on the market today. The aim of the research study is to present and compare some of the measurement methods available on the market for level measurement. In the study, the models for pressure sensors, flow sensors, ultrasonic sensors and electromagnetic sensors are compared to see which sensor is most suitable for precise measurements of water levels. Through the data collection from the search engines Google scholar and Mid University of Sweden own database Primo, facts have been gathered. The information has since been processed and compared to the needs of Vattenfall, which will do three sensor changes at the Stugun hydropower plant. The result of the study showed that according to the requirement specifications of Vattenfall, a pressure sensor was the best alternative for Stugun. The study resulted in Vattenfall purchasing three Waterpilot FMX21, 22 mm, which were then put in place and calibrated.
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Dankoco, Mariam Dème. "Conception et réalisation de capteurs (température et pouls) imprimés sur support souple." Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4318.
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La thèse s’inscrit dans le cadre du projet de recherche collaborative VEADISTA (Veille à distance et alerte intelligente) qui repose sur la conception d’une technologie ergonomique à bas coût. L’objectif de cette thèse est de concevoir et de réaliser des capteurs de température et de pression imprimés sur support flexible pour des applications biomédicales. Ils doivent être adaptés à une intégration sur un transpondeur passif télé-alimenté, conformables pour s’adapter au bras du patient, bas coût et permettant un transfert technologique vers l’industrie.Des prototypes de tests ont été réalisés dans le but d’identifier la topologie et la couche active les plus prometteuses pour la réalisation des capteurs de température en tout imprimé sur support souple. A l’issue de cette étude préliminaire, une thermorésistance à base d’encre d’argent a été réalisée par jet d’encre sur un substrat flexible. La caractérisation de ces capteurs a permis d’évaluer leur sensibilité et d’attester de leur bonne linéarité.Des tests préliminaires sur des capteurs commerciaux ont ensuite été effectués pour démontrer qu’il était possible de détecter le rythme cardiaque avec un capteur de pression. A la suite de cette étude, des capteurs de pression sur support souple ont été fabriqués en utilisant la technologie jet d’encre. Ces capteurs ont été caractérisés électriquement sous contrainte mécanique contrôlée. Pour aboutir à ces résultats, de nombreux développements technologiques ont été réalisés autour de la technique d’impression par jet d’encre. La maîtrise du triptyque encre-tête d’impression-substrat est en effet indispensable pour l’obtention de motifs de qualitéThis thesis is a part of the collaborative research project VEADISTA (Remote monitoring of vital parameters and smart alerts) based on the conception of an ergonomic technology at low-cost.The objective of this thesis is to design and to realize printed temperature and pressure sensors on flexible support for biomedical applications. Subsequent to this, these sensors must be suitable to an integration on a passive transponder remotely powered, conformable to fit the patient's arm, low cost and allowing a technological transfer towards industry.Prototype tests were realized in order to identify the most promising topology and active layer to achieve printed temperature sensors on flexible support. At the end of this preliminary study, a RTD based on a silver ink was performed by inkjet on a flexible substrate (Kapton). The characterization of these sensors allowed to assess their sensitivity and to attest to their good linearity.The preliminary tests on commercial sensors were then made to demonstrate that it was possible to detect the heart rate with a pressure sensor. Following this study, pressure sensors were manufactured on flexible support using inkjet technology. These sensors were electrically characterized under controlled mechanical constraint. To achieve these results, many technological developments were realized around the inkjet printing technique. The mastery of the ink – inkjet head – substrate interaction is indeed essential for obtaining good printed quality and functional sensors
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Caillier, Christophe. "Transport électronique dans les nanotubes de carbone individuels sous conditions extrêmes." Phd thesis, Université Claude Bernard - Lyon I, 2009. http://tel.archives-ouvertes.fr/tel-00454234.
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Cette thèse a pour objet l'étude des propriétés de transport électronique des nanotubes de carbone soumis à des pressions hydrostatiques de l'ordre du gigapascal. L'originalité de ce travail réside dans le fait d'étudier ces propriétés sur des nanotubes individuels. Ceci permet de simplifier la géométrie du système et de faire apparaître des comportements propres à chaque type de nanotubes. Le cas d'un nanotube multifeuillets composé d'un tube externe à faible bande interdite et d'un tube interne métallique a permis d'observer i) l'évolution sous pression de la barrière de Schottky aux contacts or-nanotube, ii) l'évolution de la résistance inter-feuillet, mettant en évidence une transition associée au changement de section du nanotube, iii) la diminution de l'hystérésis en tension de grille. D'autre part, une étude systématique sur des nanotubes métalliques permet de faire ressortir un comportement général pour le contact or-nanotube sous pression, indépendant de la chiralité du nanotube et du milieu transmetteur de pression. Nombre de ces effets peuvent être utilisés pour des applications électroniques ou électro-mécaniques, tels que des capteurs de pression miniatures et environ dix fois plus sensibles que certains standards actuels. Un modèle simple de calculs par la méthode des liaisons fortes est aussi mis en œuvre afin de prédire l'évolution des propriétés électroniques des nanotubes de carbone sous pression en fonction de leur chiralité. Ce modèle permet de prédire d'autres phénomènes qui pourraient être observés grâce à une étude approfondie et systématique utilisant la méthode expérimentale développée au cours de cette thèse.
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Toumi, Dareen. "Conception et réalisation d'un système électronique ambulatoire pour l'évaluation de la microcirculation cutanée." Phd thesis, INSA de Lyon, 2012. http://tel.archives-ouvertes.fr/tel-00876656.
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La microcirculation est constituée d'un réseau vasculaire qui comprend les artérioles, les veinules et les capillaires. La microcirculation cutanée est un paramètre physiologique important pour les applications cliniques avancées comme le syndrome de Raynaud ou la prévention des escarres. De nombreuses méthodes non ambulatoires ont été développées afin de mesurer la microcirculation sanguine. La tendance actuelle dans le domaine des technologies pour la santé est la miniaturisation des capteurs et de leurs instrumentations associées pour les rendre non-invasifs, portables par le patient et ainsi adaptés aux mesures ambulatoires en conditions réelles, ou appelées aussi " écologiques ". Le manuscrit présente la conception et la réalisation d'un système électronique miniaturisé ambulatoire (µHématron), permettant de réaliser un monitoring continu, en temps réel de la conductivité thermique tissulaire qui est l'image de la microcirculation dans les capillaires. La première expérimentation effectuée a pour l'objectif de confronter le système µHématron avec un moniteur de fluxmétrie laser Doppler, au cours d'une étude destinée à évaluer le confort thermique chez l'homme. Ainsi, une étude d'influence de la température de différentes ambiances sur un certain nombre de paramètres de la peau de sujets sains, y compris la microcirculation cutanée, a été réalisée. Les corrélations obtenues entre les variations des deux signaux des deux instrumentations pour les ambiances neutres, chaudes et froides sont présentées. La deuxième expérimentation est consacrée à l'étude préliminaire de l'effet global des bas médicaux de compression sur la microcirculation cutanée des membres inférieurs de sujets sains. Grâce à l'instrumentation ambulatoire, la microcirculation a pu être évaluée de façon continue pour différentes postures des sujets : allongée, assise, débout et en marche, et ce, pour des différentes classes de bas de compression (I, II, et III). Cette étude a permis d'améliorer la compréhension de l'effet de ces bas sur les sujets sains.
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Pinela, Nuno Miguel Gonçalves. "Piezoresistive Pressure Sensor for application in e-skin devices." Master's thesis, 2017. http://hdl.handle.net/10362/26672.
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(ENG) In recent years, the advancement of science and technology tends to evolve towards the
exploitation of electronic skin (e-skin) and functional prosthetic devices, enabling innovating
applications in various fields such as biomedical systems, sports health-monitoring and
healthcare. Owing to their significant role in health monitoring, pressure sensors come as essential
components in the development of artificial systems that can mimic the impressive human skin.
The development of such sensors comprises the search for flexible and stretchable materials
suitable for implementation in robust devices that enable the integration of multiple sensingfunctionalities.
To quantitatively monitor pressure, these sensors use transduction methods based
on piezoresistivity, capacity, piezoelectricity, and triboelectricity.
In this work, piezoresistive devices were chosen over others due to their ease in structure design
and readout mechanism. The mechanism of such piezoresistive pressure sensor relies on the
transduction of a pressure change into a change in resistance that, in this case derives from
variations in the contact area. In the approach presented in this work, a semi-sphere
microstructuring patterning made by laser engraving on hard-poly(dimethylsiloxane) (h-PDMS)
was introduced. h-PDMS works as a mold from which standard-poly(dimethylsiloxane) (s-
PDMS) microstructured membranes with approximately 200 μm thickness are peeled off.
Carbonink, working as active material, was deposited on top of the microstructured s-PDMS
membranes. The fabrication of such pressure sensors based on organic membranes combines
advantages such as the production in a low-cost and fast way, device flexibility, and tunability of
the sensor’s design. Moreover, sensitivities of 2.4 × 10-1 kPa-1 were reached for the sensors
developed.(PT) Nos últimos anos, o avanço da ciência e da tecnologia tende a evoluir para a exploração da pele eletrónica (e-skin) e próteses funcionais, possibilitando aplicações inovadoras em vários campos, nomeadamente sistemas biomédicos, saúde desportiva, e monitorização da saúde. Devido ao seu papel significativo na monitorização da saúde, os sensores de pressão são componentes essenciais no desenvolvimento de sistemas artificiais que conseguem imitar a impressionante pele humana. O desenvolvimento destes sensores requer a procura por materiais flexíveis e extensíveis adequados para implementação em dispositivos robustos que permitam a integração de múltiplas funcionalidades de detecção. Para monitorizar a pressão, estes sensores usam métodos de transdução baseados em piezoresistividade, capacidade, piezoelectricidade e triboeletricidade. Neste trabalho, dispositivos piezoresistivos foram escolhidos em detrimento dos outros devido à sua fácil implementação e mecanismo de leitura. Este mecanismo consiste na transdução de uma diferença de pressão numa diferença de resistência que, neste caso, deriva de variações na área de contato. Na nova abordagem apresentada neste trabalho, introduziu-se um método de microestruturação de semi-esferas baseado na gravação a laser em poli(dimetilsiloxano)-duro (h-PDMS). O h- PDMS funciona como um molde a partir do qual se retiram membranas microestruturadas de poli(dimetilsiloxano)-standard (s-PDMS) com aproximadamente 200 μm de espessura. O material ativo em cima do domínio microestruturado é tinta de carbono. A fabricação destes sensores de pressão com base em membranas orgânicas combina vantagens como a produção de forma rápida, fabricação de baixo custo, flexibilidade do dispositivo e flexibilidade na mudança do design do sensor. Para além disso, para estes sensores foram conseguidas sensibilidades de 2.4 × 10-1 kPa-1.
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Hou, Hung Chia, and 侯宏佳. "A study on clogging behavior of the nonwoven geotextile by using electronic micro pore water pressure sensor." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/63437987471822312322.
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碩士中原大學
土木工程學系研究所
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Clogging potential is a major concern when geotextile is used in filtration/drainage systems. Various methods are available for determining the clogging potential of geotextile. Gradient ratio test (GR test) is widely applied for its convenience and shorter test duration. Chang and Nieh (1996) reviewed the conventional GR test and raised several recommendations for improving performance. Based on Chang and Nieh’s recommendations, S.Y. Chen (1996) devised a modified gradient ratio device that provides better performance of water pressure distribution over the specimen. Electronic micro pore water pressure sensor developed by the China Nanjing Hydraulic Research Institute is used instead of conventional implanted measuring tube for the study of the re-distribution of fine soil granules after the GR test. The anterior portion of the lead tube of the sensor is made of ceramic porous stone that can eliminate the interference of fine granules with interface material. The use of electronic water pressure sensor not only prevents undesirable effects during specimen preparation but also during the removal of bubbles. More importantly, it senses the water pressure distribution instantaneously. Findings indicate that for fine contents over 30%, blinding phenomenon may occur at any layer of the specimen, rather than in the 2.54cm layer above the geotextile. After the GR test, soil specimen in the 2.54cm layer above the geotextile is collected for analysis. Results reveal that the distribution of size of lost soil particles is related to the pore size of the geotextile. Findings also indicate that higher fine contents require a longer time to reach the stable state of the GR value.
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Parthasarathy, Sindhu. "Autonomous Sensor System for Self-Monitoring of Training in Shooting Sport." Thesis, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-16956.
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The factor of precision has always been the mastermind of the shooting sport. With new shooters coming into the field every day and with more aspiring shooters bringing laurels, a help of technology for training can make a difference. When advanced systems like the SCATT, Electronic Target Systems, etc. are marked for the people of the higher background, an easy handle autonomous system for self-monitoring training of precision improvement has always been a question of far reach. This project is about developing an external removable device, which will monitor and evaluate the shooter efficiency of gripping weapon, measure by pressure given at the contact points of the weapon. In the contact points, such as the trigger, the hand grip, cheek rest, butt plate and the hand rest; we use force sensitive resistors, which are connected to an automatic monitoring system built over an Arduino platform. The system analyses the shots based on the variation in the pressure at each point of contact for every shot. By further analysis and consolidation, the average pressure over a range of shots, an optimal pressure point can be fixed individually for the respective shooter. This pressure points are used as references, by rating them in comparison with the corresponding shot acquired in the target. The system includes a pre-designed training program, which autonomously monitors and trains the shooter to achieve the optimum grip in every shot, thereby increasing the accuracy and precision in a sequence of shots. With time, it helps the body to develop a muscle memory based on controlled training and learn the rhythm of applying optimum pressure to achieve better results.Noted the puBlication content is patented.
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Patel, Amit. "Electronic circuits for capacitive pressure sensors." 1990. http://catalog.hathitrust.org/api/volumes/oclc/23044829.html.
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Thesis (M.S.)--University of Wisconsin--Madison, 1990.Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 20-21).
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Gonçalves, Vera Filipa Barbosa Das Neves. "Development of Polymer-based Pressure Sensors for Electronic Devices." Tese, 2014. https://repositorio-aberto.up.pt/handle/10216/100944.
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Gonçalves, Vera Filipa Barbosa Das Neves. "Development of Polymer-based Pressure Sensors for Electronic Devices." Doctoral thesis, 2014. https://repositorio-aberto.up.pt/handle/10216/100944.
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Santos, Andreia Sofia Santana dos. "Development of Multifunctional E-skin Sensors." Doctoral thesis, 2020. http://hdl.handle.net/10362/113167.
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Electronic skin (e-skin) is a hot topic due to its enormous potential for health monitoring, functional prosthesis, robotics, and human-machine-interfaces (HMI). For these applications, pressure and temperature sensors and energy harvesters are essential. Their performance may be tuned by their films micro-structuring, either through expensive and time-consuming photolithography techniques or low-cost yet low-tunability approaches. This PhD thesis aimed to introduce and explore a new micro-structuring technique to the field of e-skin – laser engraving – to produce multifunctional e-skin devices able to sense pressure and temperature while being self-powered. This technique was employed to produce moulds for soft lithography, in a low-cost, fast, and highly customizable way. Several parameters of the technique were studied to evaluate their impact in the performance of the devices, such as moulds materials, laser power and speed, and design variables. Amongst the piezoresistive sensors produced, sensors suitable for blood pressure wave detection at the wrist [sensitivity of – 3.2 kPa-1 below 119 Pa, limit of detection (LOD) of 15 Pa], general health monitoring (sensitivity of 4.5 kPa-1 below 10 kPa, relaxation time of 1.4 ms, micro-structured film thickness of only 133 µm), and robotics and functional prosthesis (sensitivity of – 6.4 × 10-3 kPa-1 between 1.2 kPa and 100 kPa, stable output over 27 500 cycles) were obtained. Temperature sensors with micro-cones were achieved with a temperature coefficient of resistance (TCR) of 2.3 %/°C. Energy harvesters based on micro-structured composites of polydimethylsiloxane (PDMS) and zinc tin oxide (ZnSnO3) nanowires (NWs; 120 V and 13 µA at > 100 N) or zinc oxide (ZnO) nanorods (NRs; 6 V at 2.3 N) were produced as well. The work described herein unveils the tremendous potential of the laser engraving technique to produce different e-skin devices with adjustable performance to suit distinct applications, with a high benefit/cost ratio.