Electrical and Electronic Engineering - Masters by Research Theses

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    Development of a low-power, battery-less near field communication sensor transponder for wireless sensing applications
    (University College Cork, 2022-12-12) Gawade, Dinesh R.; Buckley, John; O'Flynn, Brendan; Horizon 2020; Science Foundation Ireland; European Commission
    Cultural heritage objects and artefacts are precious objects owned by museums and archives, which are generally old and fragile. Often, such objects are stored in climatically uncontrolled storage areas, particularly inside sealed archive boxes and storage crates. Such storage practices can lead to significant degradation of valuable artefacts. Implementing air conditioning and heating, ventilation, and air conditioning (HVAC) systems constitutes a highly technical conservation challenge that often cannot be financially justified, especially for small and medium-sized museums. Commercially available environmental sensors, such as hygrometers and wireless data loggers are known for monitoring microenvironments in museums. However, these devices are unsuitable for integration within museum storage boxes because these sensors are either too large or expensive. For example, the Testo series 160TH data logger can be used for monitoring temperature and humidity in museum environments but the cost is significant at approximately €245. Another critical disadvantage associated with monitoring the inside microenvironments of an archive box using a hygrometer is the necessity to open the box for the analysis. A key disadvantage of existing methods is the interference caused to the internal microclimate. This thesis presents the development of both short-range and long-range wireless sensor platforms that monitor the microclimatic environment inside museum artefact storage boxes. The short-range wireless communication platform focuses on developing a battery-less near-field communication (NFC) sensor transponder with a wireless communication range of several centimetres. On the other hand, the long-range communication platform development involves the selection and implementation of optimum wireless communication technology to yield a wireless communications range of 100 metres to several kilometres and which is scalable according to the large number of artefacts that may need to be monitored. In the first contribution, for the first time, a smart museum archive box that features fully integrated wirelessly powered temperature and humidity sensing capabilities is developed and demonstrated. The developed NFC sensor transponder has been optimized for low power operation using voltage and frequency scaling techniques with a measured peak DC power consumption of 597 μW while yielding a 5 cm wireless communication range. The achieved power consumption is 33.6 % lower in comparison with the current state-of-the-art in this area. In addition, the developed battery-less NFC sensor transponder can wirelessly measure temperature and relative humidity with a mean error of ± 0.37 ◦C and ± 2 %, respectively, over a maximum distance of 5 cm. In addition, a battery-less NFC humidity sensor prototype is developed and demonstrated using laser-induced graphene (LIG) electrodes and a graphene oxide (GO)-based humidity sensor. Furthermore, the feasibility of enhancing the wireless communication range of the NFC sensor transponder is explored. This is achieved by powering the transponder electronics using energy harvested from a vibrational energy harvester. A maximum wireless communication range of 11 cm is achieved in free space, which is 120 % beyond the state-of-the-art reported in the literature. Finally, the developed battery-less NFC sensor transponders were deployed in Cork Public Museum, Cork, Ireland and Fondazione Scienza e Tecnica (FST) in Florence, Italy to monitor artefacts in these museums. In addition, the transponder was also deployed in the world-famous Guggenheim museum in Venice, Italy, to monitor the interior temperature and humidity of Andy Warhol’s painting entitled flowers. In the second contribution, the optimum wireless communication technology for museum artefact monitoring applications in warehouses and exhibition cabinets was identified. For the identified technology (LoRaWAN), a testbed network was developed and deployed (7 sensor nodes) as proof of concept at Cork Public Museum, Cork, Ireland, to monitor the interior temperature and humidity of artefact display cases and storage cabinets. The wireless communication performance of LoRaWAN is shown to offer the optimal solution for wireless communication for this long-range application with a measured packet delivery ratio of 0.994 and an estimated battery lifetime of 10 years, considering a duty cycle of 1 data packet per day. The outcomes of this thesis contribute to the advancement of museum artefact monitoring, battery-less NFC sensing state-of-the-art for short-range storage analytics and a LoRaWAN solution for long-range analysis of warehouse cabinets and exhibitions.
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    Monolithic, tunable, single frequency, narrow linewidth lasers using quantum well intermixing
    (University College Cork, 2022-06) Jia, Zhengkai; Peters, Frank H.; Hao, Guangbo; Science Foundation Ireland
    With the development of Internet technology, the number of Internet users and Internet traffic has increased exponentially every year, and there is a large-scale demand for photonic components at the core of optical communication networks. Semiconductor lasers are the heart of photonic devices which are attractive for their low form factor, mass producibility and compatibility with photonic integrated circuits (PICs). Quantum well intermixing (QWI) is one of the important monolithic techniques used in the integration of PICs. QWI is a post-growth technique, which is used in the preparation of integrated devices and creates a modified energy band gap of a quantum well without any regrowth. QWI in Indium phosphide (InP) based AlGaInAs multiple quantum well active regions was demonstrated in this dissertation by applying QWI to monolithic tunable single frequency narrow linewidth lasers. This design reduces both the potential cost and power consumption of the devices. This work has been focused on creating small size coherent optical laser sources, making them attractive devices to satisfy the rising demand for photonic components. This work investigates the development of components that can be simply fabricated without requiring any epitaxial regrowth. A regrowth-free monolithic InP-based laser / photonic integrated circuit (PIC) was demonstrated with tunable single-frequency operation in the C + L bands and a sub 10 kHz linewidth. The laser PIC integrates a gain section with a 1×2 multimode interferometer (MMI), a linear curvature ring reflector on one side and a slotted mirror on the other. The MMI and ring reflector were made transparent to the gain wavelength using the impurity-free vacancy disordering (IFVD) quantum well intermixing technique to extend the cavity for narrow linewidth. The slotted mirror acts as higher order distributed Bragg reflector (DBR) to select the lasing mode. The laser was fabricated using the typical Fabry Perot (FP) laser process used in the Integrated Photonics Group, with a self-aligned technique for achieving two etch depths. The fabricated laser demonstrated single longitudinal mode tunability over a 39 nm range with a side mode suppression ratio (SMSR) of greater than 35 dB and a 3.79 kHz linewidth at room temperature with 87 mA current injection on the gain section and 115 mA on the slotted mirror section.
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    A drifter-based self-powered piezoelectric sensor for ocean wave measurements
    (University College Cork, 2022-07-01) Kargar, Seyyed Masoud; Hao, Guangbo; Kavanagh, Richard; European Regional Development Fund
    In the present research, a drifter-based piezoelectric sensor is proposed to measure ocean waves’ height and period. To analyze the motion principle and the working performance of the proposed drifter-based piezoelectric sensor, a dynamic model is developed. The developed dynamic model investigates the system’s response to an input of ocean waves and provides design insights into the geometrical and material parameters. Next, finite element analysis (FEA) simulations using the commercial software COMSOL-Multiphysics have been carried out with the help of a coupled physics analysis of Solid Mechanics and Electrostatics Modules to achieve the output voltages. An experimental prototype has been fabricated and tested to validate the results of the dynamic model and the FEA simulation. A slider-crank mechanism is used to mimic ocean waves throughout the experiment, and the results show a close match between the proposed dynamic modeling, FEA simulations, and experimental testing. In the end, a short discussion is devoted to interpreting the output results; comparing the results of the simulations and the experimental testing; the sensor’s resolution; and the self-powering functionality of the proposed drifter-based piezoelectric sensor.
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    Low-latency architectures for piezo-driven wearable haptic devices for industry 4.0 applications
    (University College Cork, 2021) Kundu, Souvik; O'Flynn, Brendan; Torres Sanchez, Jeronimo Javier; Menolotto, Matteo; Walsh, Michael; Science Foundation Ireland
    The aim of the thesis is to advance the state of the art in the area of Human Computer Interaction (HCI) for Industry 4.0, with a focus on reducing the end to end latency of the HCI tactile technology. The ambition of the work being to develop technology to help the HCI overall round trip achieve the sub-millisecond latency goal, which is seen as the next revolution of the “tactile internet”. After analysing the latency model it is identified that the major source of delay is coming from piezo haptic driver block. This led to a detailed analysis of piezo haptic driver architectures and to proposing three novel architectures for such drivers. The proposed solutions have been modelled and simulated in MATLAB and MULTISIM and, following satisfactory model/simulation results, the PCB design has been implemented, manufactured and tested. The test results show a reduction of latency in the proposed novel piezo haptic drivers when compared to the current commercially available state-of-the-arts. Moreover, the custom piezo haptic drivers designed and described in this thesis surpass the capabilities of commercially available drivers in terms of the amplitude range, frequency range and shape of the output waveform, which is an essential feature for the creation of different tactile perceptions/effects and to ensure compatibility with a wide range of piezo actuators. In addition, the small footprint and low latency along with static power mode (temporary shutdown of power to the components while not in use) make it ideal for battery-powered wearable devices. The developed ultra-low latency piezo haptic driver could play a key role, for instance, in real-time teleoperation (especially in telerobotic operation) and in enhancing immersive experience in AR/VR applications, and presents a significant contribution towards achieving the overall round trip 1-millisecond latency goal for the tactile internet. Future studies will explore the development of the technology into an integrated circuit with low-power multi-piezo actuation capability and the integration of the technology as part of the next generation of the Tyndall HCI data glove, a tactile enabled wearable hand motion-tracking device.
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    Development of an acoustic telemetry platform for underwater sensing
    (University College Cork, 2021-11-14) Jafarzadeh, Hamed; O'Flynn, Brendan; Belcastro, Marco; H2020 European Research Council; Science Foundation Ireland
    With the advancement of electromagnetic communication technologies, it is now possible to transmit data wirelessly over tens of kilometers using a limited energy source which enables industries and researchers to build sophisticated wireless sensor networks in the terrestrial environment for various use cases. While there has been much progress in terrestrial electromagnetic wireless communication in recent years, underwater wireless communication has not received the same focus, and unsolved problems remain in terms of power consumption, miniaturisation, and data rates in marine-based underwater wireless sensor networks. Currently, there are a variety of sensors that can be deployed underwater, but to retrieve their data, either they must have a wired connection to the surface, or they must be physically collected to download the data after retrieval. Having a wireless underwater telemetry platform can significantly reduce the cost and efforts of deployment of marine sensors, eliminate the need for periodic sensor collection for data download, improve the reliability of underwater sensors by eliminating the need for wires and cables and provide real-time insights into the underwater sensory condition for multiple applications. IMPAQT is a European research project aiming at the development of the technologies and methods to promote and support inland, coastal zone, and offshore Integrated Multi-Trophic Aquaculture (IMTA) sites. An underwater wireless sensor network can be hugely beneficial to the farmers as a monitoring tool that can provide real-time data sets as to the conditions in an IMTA site to help optimise conditions for growth and maximise the productivity of the aquaculture activities, as well as to potentially lead to taking early interventions against adverse events. This thesis describes the design of the IMPAQT underwater ultrasonic wireless telemetry platform that has the potential to enable the building of small, dense wireless sensor monitoring underwater. The IMPAQT underwater telemetry platform provides a general-purpose, low-cost, low-power, miniaturized transmitter node, in a one-way communication platform for marine sensor data collection. The IMPAQT underwater telemetry platform consists of ultrasonic transmitter nodes which can be configured in a star network and a receiver node to be used as a data aggregator and surface link for the transmitter (sensor) nodes. The transmitter node runs on a battery and provides an I/O interface through wired SPI/UART connection, wired analogue ports, and optical UART communication to be used with a variety of commonly used underwater sensors. The transmitter node periodically collects sensor information and transmits it wirelessly to the receiver node. The receiver node, which is designed to exist above the surface of the water (in a buoy or mounted on a cage), logs the transmitted information for manual collection or for transfer of the collected information to the cloud via long-range radios, e.g., GSM/LoRa to an inland data aggregator.