The thesis focuses on the possibilities of objective stress measurement. It chooses parameters that are suitable for measurement by commonly available wearable electronics. It establishes a methodology for measuring stress using these devices, which it then verifies by conducting experiments with flight school students. It serves as proof of concept for similar measurements in further research or in flight schools.

Forskningsområdet för bärbar elektronik är fortfarande relativt ungt och det finns ett stort behov av utveckling av nya material inom området. Olika typer av kompositer är mycket intressanta och de ska uppvisa såväl hög hållfasthet som goda ledande egenskaper. I detta avseende är silkes fibroin och MXene mycket intressanta utgångsmaterial eftersom silkestrådarna kan ge en struktur med god jonledningsförmåga och god flexibilitet och MXene kan bidra med hög styvhet och god elektrisk ledningsförmåga. Med detta som bakgrund beslöts att undersöka om kompositer av silkestrådar och MXene kan användas i kompositer som kan användas i bärbar elektronik. 3 olika typer av hydrogeler studerades och de innehöll silkes fibroin med 0, 1 och 5% MXene. De egenskaper som utvärderades var struktur, mekaniska egenskaper, stabilitet i vatten, bionedbrytbarhet och både statisk och dynamisk ledningsförmåga. Resultaten visar att de tillverkade nanokompositerna har lovande förutsättningar inom området eftersom en kombination av silkes fibroin med 5 % MXene har god stabilitet, konduktivitet och en hög och stabil Gauge-faktor. / As the research area of wearable electronics is still relatively new, material science with this focus opens plenty of unexplored fields. That is why a study characterizing the unexplored composite system of silk fibroin and MXene (Silk/MXene) was conducted. These two biocompatible materials are complementary with regard to the requirements for wearable electronics materials. Silk fibroin dispose an ionic conductivity and solid flexibility, while MXene brings mechanical strength and significant increase of electrical conductivity. The reinforced hydrogel materials were studied at two concentrations of fillers, 1% and 5% and compared to pristine silk fibroin. All three materials were studied from the point of view of their structure, mechanical properties, behaviour in aqueous environment, biodegradability and electrical conductivity, both static and dynamic. Nanocomposite systems of silk fibroin and MXene have shown a potential for being used in the intended application area, as Silk/MXene 5% film displays good stability, conductivity with high andstable Gauge factor.

Internet of Things(IoT) has in recent years become a topic of broad and current interest. The purpose of this thesis is to anticipate weather conditions by constructing a system for collecting information about atmospheric pressure. The development of the system will solve the following problem: it should be possible to implement a system that allows for the collection of information from sensors through a mobile phone. The problem was solved through an iOS application together with a Micro Controller Unit (MCU) and a sensor. To collect weather data, the BME280, with its atmospheric pressure, temperature and humidity sensor, was used. Bluetooth was chosen for the interaction between the Automat and the iOS application. This proved to be a possible solution to a problem in a growing area of application. An advantage to this hardware solution is the mobility and flexibility of the Automat, making it ideal for mobile IoT solutions. Arduino is, however, the better choice for developers, as it has a larger community and clear documentation. / Internet of Things (IoT) har på senare år blivit ett alltmer omtalat område. Syftet med tesen är att förutspå väderförhållanden genom att konstruera ett IoT system som samlar in information om lufttryck, detta för att besvara frågeställningen: Det bör gå att samla in sensordata med hjälp av mobiltelefon. För att besvara detta följdes Ekholms modell för teknisk forskning och arbetsmetoden Scrum. Frågestallningen löstes genom en iOS applikation med tillhörande Microcontroller Unit(MCU) och sensor. För att samla in väderdata användes sensorn BME280, som har lufttrycks-, temperaturoch luftfuktighetssensorer, tillsammans med MCU:n Automat. För interaktionen mellan Automat och iOS applikationen tillämpades bluetooth-kommunikation. Detta var en möjlig lösning på ett problem i ett växande tillämpningsområde. Fördelar med denna lösning av hårdvara är att den är välanpassad till mobila IoT lösningar tack vare Automats minimala storlek i förhållande till funktionalitet. I många fall är däremot Arduino ett bättre val för utvecklaren, då den har större samfund och tydligare dokumentation.

<p dir="ltr">Developing functional metallic nanostructured surfaces has seen significant growth in various applications, including sensors, electronics, and biomedical devices. However, conventional fabrication techniques for these nanostructures face limitations such as complexity, high costs, and unstable coatings. Laser-assisted surface processing has emerged as a promising solution to address these challenges by enabling localized processing and modification without altering bulk properties. This dissertation focuses on the development of multifunctional devices using selective laser processing of metallized surfaces, categorized into three routes. The first part explores the utilization of laser-induced oxides (LIO) for simple processing and formation of functional metal oxide nanostructures as electrochemical sensing elements. Different laser processing conditions were systematically studied for cost-effective metals like copper and nickel, evaluating their potential as non-enzymatic glucose sensors. The second part investigates laser selective processing for removing metal coatings on temperature-sensitive substrates, providing a cost-effective and scalable alternative to conventional photolithography and etching processes. Various laser processing conditions were examined to achieve selective patterning of metalized fabric structures for wearable electronics production. The third part explores localized laser processing to create intermetallic nanotexturing mixtures without altering bulk properties. The study involved silver spray- coating onto titanium implants, followed by a post-laser processing. The aim was to achieve simultaneous texturing and intermixing of silver in titanium alloy structures, enhancing antibacterial properties and bone mineralization while preserving mechanical properties.</p><p dir="ltr">Through the comprehensive examination of these three routes, this dissertation demonstrates the immense potential of commercial laser processing systems in the design, fabrication, and characterization of functional metallic nanostructured surfaces. It emphasizes the often-overlooked aspect of chemical alterations in laser-assisted surface processing, bridging the gap between physical and chemical modifications. The research opens new avenues for the development and optimization of multifunctional devices in electronics and biomedical applications.</p>

Various nano-fillers can introduce specific functions into polymer and expand their application areas. Myriad properties, such as mechanical, electrical, thermal, or magnetic properties can be combined with original polymer characteristics, including flexible, light weight, and ease of use. These composites can be used to produce multi-functional fibers as the next generation textile or fabrics. In this research, Polyacrylonitrile (PAN) is adopted as the main polymer with different nano-fillers, such as carbon nanotube (CNT), iron oxide nanoparticle, and graphene oxide nanoribbon (GONR). Using gel-spinning technology, PAN-based composite fibers are fabricated in single- or bi-component fibers. Fibers are also characterized for their structure, morphology, mechanical properties, as well as for their electrical, thermal, or magnetic properties. For example, bi-component fibers with polymer sheath and polymer-CNT core as well as polymer-CNT sheath and polymer core are processed. With electrical and thermal conductivity introduced by CNT, such bi-components fibers can be applied for wearable electronics or for thermal management. Joule-heating effect owing to applied electrical current on single component PAN/CNT fibers is also investigated. With controllable electrical conductivity and fiber temperature, this active functional fiber can be applied for temperature regulation fibers or new carbon fiber manufacturing process. Another example is magnetic fiber with superparamagnetic iron oxide nano-particles. These novel magnetic fibers with high strength can be used for actuator, inductors, EMI shielding, or microwave absorption. GONR is also discussed and used to reinforce PAN-based fibers. Several theoretical models are considered to analyze the observed results.

This thesis investigates inkjet printing of fully-integrated modules fabricated on organic substrates as a system-level solution for ultra-low-cost and eco-friendly mass production of wireless sensor modules. Prototypes are designed and implemented in both traditional FR-4 substrate and organic substrate. The prototype on organic substrate is referred to as a Smart Wireless Integrated Module (SWIM). Parallels are drawn between FR-4 manufacturing and inkjet printing technology, and recommendations are discussed to enable the potential of inkjet printing technology. Finally, this thesis presents novel applications of SWIM technology in the area of wearable and implantable electronics. Chapter 1 serves as an introduction to inkjet printing technology on organic substrates, wireless sensor networks (WSNs), and the requirements for low-power consumption, low-cost, and eco-friendly technology. Chapter 2 discusses the design of SWIM and its implementation using traditional manufacturing techniques on FR-4 substrate. Chapter 3 presents a benchmark prototype of SWIM on paper substrate. Challenges in the manufacturing process are addressed, and solutions are proposed which suggest future areas of research in inkjet printing technology. Chapter 4 presents novel applications of SWIM technology in the areas of implantable and wearable electronics. Chapter 5 concludes the thesis by discussing the importance of this work in creating a bridge between current inkjet printing technology and its future.

<div>Recently, energy crisis and environment pollution has become global issues and there is a great demand for developing green and renewable energy system. At the same time, advancements in materials production, device fabrication, and flexible circuit has led to the huge prosperity of wearable devices, which also requires facile and efficient approaches to power these ubiquitous electronics. Piezoelectric nanogenerators and triboelectric nanogenerators have attracted enormous interest in recent years due to their capacity of transferring the ambient mechanical energy into desired electricity, and also the potential of working as self-powered sensors. However, there still exists some obstacles in the aspect of materials synthesis, device fabrication, and also the sensor performance optimization as well as their application exploration.</div><div>Here in this research, several different materials possessing the piezoelectric and triboelectric properties (selenium nanowires, tellurium nanowires, natural polymer hydrogel) have been successfully synthesized, and also a few novel manufacturing techniques (additive manufacturing) have been implemented for the fabrication of wearable sensors. The piezoelectric and triboelectric nanogenerators developed could effectively convert the mechanical energy into electricity for an energy conversion purpose, and also their application as self-powered human-integrated sensors have also been demonstrated, like achieving a real-time monitoring of radial artery pulses. Other applications of the developed sensors, such as serving as electric heaters and infrared cloaking devices are also presented here. This research is expected to have a positive impact and immediate relevance to many societally pervasive areas, e.g. energy and environment, biomedical electronics, and human-machine interface.</div><div><br></div>

This report describes the development process of the mobile application HealthyWay. The application is developed as a Bachelor thesis project together with KTH Royal Institute of Technology. The applications' main function is to be the interface to a number of wearable medical electronic appliances such as bandages and pill boxes. The communication is done through Bluetooth Low Energy. The application was mainly written in 3 di erent languages, QML, C++ and Java. The most stressed point throughout this project was the importance of platform independence. The exibility had to be done on a scalable as well as on a modular level. With this in mind, QT was used to address the requirement of scalability. The modularity was achieved through an organized structure to the program accompanied by easy directives to introduce new devices. The purpose of the application is to increase the quality of life for the user. This intent could however not be concluded due to the lack of testing among users. In its current state, the application is not yet ready for deployment but instead acts as a framework for future prospects. / Den här rapporten beskriver utvecklingsprocessen för en mobilapplikation vid namn Healthy- Way. Applikationen är utvecklad som ett kandidatexamensarbete tillsammans med KTH. Applikationens huvudsakliga uppgift är att vara ett gränssnitt till medicinskt relaterad utrustning såsom plaster och pilleraskar. Kommunikationen mellan dessa sker via Bluetooth Low Energy. Applikationen skrevs huvudsakligen i 3 olika språk, QML, C++ och Java. Den viktigaste punkten genom projektets gång var att applikationen skulle vara oberoende av plattform. Flexibiliteten var tvungen att göras på både en skalbar och modulär nivå. Med detta i åtanke valdes QT för att behandla skalbarheten. Modulariteten uppnåddes genom en välplanerad struktur på programmet tillsammans med instruktioner på hur ny utrustning kan introduceras. Syftet med programmet är att öka livskvaliteten för användaren. Detta syfte kunde däremot inte slutföras på grund av bristande testning hos användare. I dagens läge är applikationen inte redo för att släppas kommersiellt, men tjänar som ett bra ramverk för framtida utveckling.

A wearable body temperature sensor would allow for early detection of fever or infection, as well as frequent and accurate hassle-free recording. This thesis explores the design of a body-temperature-sensing device inkjet-printed on a flexible substrate. All structures were first modeled by first-principles, theoretical calculations, and then simulated in HFSS. A variety of planar square inductor geometries were studied before selecting an optimal design. The designs were fabricated using multiple techniques and compared to the simulation results. It was determined that inductance must be carefully measured and documented to ensure good functionality. The same is true for parallel-plate and interdigitated capacitors. While inductance remains relatively constant with temperature, the capacitance of the device with a temperature-sensitive dielectric layer will result in a shift in the resonant frequency as environmental or ambient temperature changes. This resonant frequency can be wirelessly detected, with no battery required for the sensing device, from which the temperature can be deduced. From this work, the optimized version of the design comprises of conductive silver in with a temperature-sensitive graphene oxide layer, intended for inkjet-printing on flexible polyimide substrates. Graphene oxide demonstrates a high dielectric permittivity with good sensing capabilities and high accuracy. This work pushes the state-of-the-art in applying these novel materials and techniques to enable flexible body temperature sensors for future biomedical applications.

Dissertation thesis is focused on using alternative energy sources called energy harvesting. This thesis offers a solution to problems with autonomous powering of sensor networks if primary power source recovery is impossible. In these cases, energy of the external power (e.g. temperature, light, motion) should be used. Proposed solution should be especially used in the field of medical applications (e.g. cochlear implants, pacemakers, insulin pumps). Long time monitoring of the personal health status is also possible when employing automated sensor systems. In this work, there is state of art review relating to the low power energy sources for an alternative powering of sensor systems. It was observed that existing systems are almost prepared for the implementation of energy harvesting power sources. The energy harvesting power sources have been developed by numerous researcher teams around the world, but there are only a few variants of power management circuits for effective energy gaining, storing and using. This area has a huge potential for the next research. The issues regarding to the distribution of gained energy are solved on the complex level in the thesis. For these purposes, a new simulation model of the whole system (fully implantable artificial cochlea) including its subcircuits was developed in the SPICE environment. It connects independent subcircuits into a single comprehensive model. Using this model, a few novel principles for energy distribution (e.g. Charge Push Through technique) was developed. In the near future, these techniques are also applicable to the design of versatile sensor systems.