This project aims to develop a wearable device to assist visually impaired individuals in identifying obstacles when entering unfamiliar rooms. Using advanced distance sensors, it provides real-time haptic feedback, enabling users to map and navigate their surroundings safely and independently. This development has been guided by insights from visually impaired individuals themselves, with the goal of creating a device that integrates seamlessly into their daily lives. The primary objective is to enhance the quality of life for visually impaired people by promoting greater independence and safety without relying on a guiding stick. Existing solutions often fail to provide real-time and accurate information to the users. This wearable device addresses this gap by offering reliable distance sensors and immediate feedback through vibration signals, empowering users to navigate spaces independently and confidently.

A new concept is developed for a medical rehabilitation device. User research, literature review, market analysis, and expert interviews are done to inform design requirements and spark ideas. Ideation uses brainstorm, sketches, and rapid prototyping to explore possible mechanisms to achieve desired affects. These mechanisms are formed into 3 devices that are then validated by a rehabilitation expert. With these insights, further development aims to improve function, form, usability, and efficacy. User tests are conducted with the final prototype, providing valuable feedback for the company to continue with.

Most injuries in football occur in the lower extremities due to high muscle stress. To prevent such injuries, the Dutch Football Association (KNVB) and the Delft University of Technology developed the Smart Sensor Shorts, an inertial sensor-based tracking system measuring the athlete’s lower body kinematics, to improve physical load estimates during training sessions and matches. However, the system currently only has offline data analysis software, which results in poor monitoring capability.

This thesis proposes a near real-time data analysis system for Smart Sensor Shorts, featuring an automatic sensor calibration module, a football-specific activity recognition module, and a user interface, to monitor users' lower limb movement and load during football training. The proposed automatic sensor-to-body calibration algorithm maintains a high calibration accuracy with an 18.92º(±5.74º) calibration error on average and simplifies the calibration process by leveraging detected standing and walking movements to estimate calibration parameters. The proposed gradient-boosting decision trees activity recognition model utilizes hip joint angles and joint angular velocities derived by the system to predict users' football-related activities, achieving an overall accuracy of 93.62%. The designed system processes the data recorded by IMUs in real time with a speed of 21 milliseconds per iteration and displays the calculated results related to the user's physical load on the user interface at a frame rate of 20 Hz.

This graduation project follows the process of researching, developing and creating a demonstrator for a surface design using the electroluminescent material - EL for short - a sandwich structured composite that emits light when alternating current flows through it. The project kicks-off with an analysis phase where the electroluminescent material and relevant client products are introduced. This includes a detailed description of the EL material from working principle to pre-fabricated versions possible to purchase from online stores. Next the EL materials themselves and A+N products were tinkered with. New DIY techniques are introduced which can help to create quick prototypes. This phase also was helped by three searches: experiential characterisation, luminescence measurement and connecting a sample to an oscilloscope to see how frequency affects the colour output. The surface design phase started with rapid prototyping ideas; a few selected ones were iterated on and turned into phosphor covered models that light up under UV light. The chosen concept direction is a set of twisted stripe designs that can be organised into a large pattern on a wall. The concept development started with creating all the elements of the tile set and some possible large patterns. During a long iteration phase the final version of the concept - a simple tile set with two different twist designs was developed. The last chapter describes the production of the demonstrators; the making of the EL sheets and then the assembly steps. The chapter introduces the final design - the LUX TWIST tile site. The LUX Twist Tile set is a modular surface installation that uses electroluminescent (EL) material to create an illuminated 3D pattern on a wall. The base module is a tile with twisted electroluminescent strips on it. The set consists of different tile designs, the featured twist comes in a curved and a straight option, available in left and right orientations. An empty tile is also part of the set to increase the variety of creatable patterns. The tiles can be connected with wire plugs at the back, which allows the current to flow from one to another. The last tile has to be connected to an inverter, then it can be plugged into a socket. The size of the installation and the pattern created with the different tiles can be completely customized to fit a desired environment and lighting conditions.

Nowadays, people are using more and more technology to measure their body performances like smart watches, heart rate sensors etc. These are all separate devices. What if it were possible to integrate these into something we wear daily. Textiles are something everyone wears daily. It is a promising medium to integrate electronics in. Especially through knitting new possibilities arise. Different conductive and non-conductive yarns are explored with a focus on off-the-shelf available materials. The main yarn needing to be elastic to get the fabric back to its normal position after stretching. Knitted fabrics have a unique structure which is perfectly suited to create sensors with. A knitted fabric is stretchable without the yarn needing to be stretchable. This makes searching for good working conductive yarns easier, as non-stretchable conductive yarns are a lot more common. Previous research shows that creating sensors through knitting is possible and can be achieved with simple yarns. The structure of knitted fabrics is mainly useful for creating strain sensors. Using elastic yarn with silver conductive plated yarns, different sensor test samples are created. Optimization is done to improve the sensors' signal output. Two directions for knitting a sensor were tested. The optimized sensors are used in two prototypes that are able to measure the movement of the arm and the breathing pattern of the wearer. The arm movement prototype is tested with two sensors knitted in the vertical (wale) direction and the breathing sensor was made with a long strip of a sensor knitted in the horizontal (course) direction. Both arm and breathing sensors are integrated into a full garment prototype. This prototype is tested by doing different movements and seeing how movements affect the sensor behaviour. Possible designs of a shirt with integrated arm and breathing sensors are briefly discussed to show how the look of the shirt and the integrated sensors could complement each other. The final prototype's sensor data is evaluated and recommendations are made for follow up projects based on this research. This research sets a new and fruitful step in the direction of producing commercially viable body measurement clothing for the near future.

Since technological devices become smaller and our devices are more fused with our bodies, the logical next step is that technology will be placeable on our skin. In this thesis the design process towards a useful application of an interface on the skin is described. To get towards this design, several methods are used in the process. To shape the design challenge, a VIP inspired method is used, which provides a clear design goal and domain. For further developing the design, a user-centered approach is used, where the use of small prototypes helps improve the design. This resulted in a tattoo-like interface on the skin, which enables the user to have more unexpected interactions with others around him. This has been designed as a counter product towards the trend of people turning towards their devices in public situations. This tattoo offers a way of increasing real social interaction, and therefore decreases the social need of interaction through our smart devices. The design can be customly build up to fit the corresponding context, which makes it applicable in many social situations where people might have the need for more social interactions.

As solar energy finds its way into unexpected applications such as buildings or objects, the traditional rectangle-shaped module becomes inadequate. Although traditional modules have been optimized to deliver a large amount of power, they cannot be fitted easily into a façade or a wearable. This is why, new methods for integrating solar power into buildings and products have to be found. These methods should be attractive to designers and architects and must also allow solar energy to reach common people.
The fabrication of mini-modules can help with this task as they can be fabricated with the already mature technology of crystalline silicon solar cells. They can be made lightweight and in different figures.
This work aims to investigate ways to facilitate the fabrication of modules for use in Building Integrated Photovoltaics or Product Integrating Photovoltaics by means of studying the impact of cutting solar cells into different figures and sizes. To prove the suitability of tools of full-sized modules into mini modules, a Cell-To-Module analysis is performed.
The results show that crystalline silicon can be effectively used for making modules in reduced sizes tackling the full integration of solar cells into objects.

In football, a lot of hip and thigh muscle injuries occur as a result of high muscular loads due to accelerative leg movements. To prevent muscle damage and optimise performance, it is essential to continuously identify when and how frequent local hip and thigh muscular loads develop in the explosive and dynamic football environment. The currently used method is an acceleration index based on two-dimensional position data of the whole global body measured by the Local Positioning Measurement system. The problem is that this system does not correspond with the experienced load of players because leg movements are excluded. Therefore, this study introduces a new local concept of gathering local three-dimensional leg acceleration data by inertial measurement units.
This pilot study aims to use a big data analysis approach to translate leg acceleration data into a measure to indicate local muscle load and compare this new local and the current global method to the players’ experienced load. Five participants performed specific football drills with an intensity increase from jogging to sprinting and by adding a pass and shot. Measures are developed, based on the pelvis, upper leg, and lower leg accelerations, by a peak and cumulative data analysis approach. By evaluating trend percentages of the intensity increase, it is obtained that a local acceleration measure is comparable to the players’ experienced load if it considers the sum of normal or peak data points weighted per zone and per travelled distance. Furthermore, a similar result is obtained when only the upper leg or lower leg accelerations are considered.
It can be concluded that local three-dimensional acceleration of the lower extremities, processed with a big data analysis approach, represent the football players’ experienced muscular load more accurate than the current global method. Further research, including a higher number of participants, should prove the significance.

Multiple studies indicated that the degree of muscle strain is the most relevant parameter in understanding the injury mechanism behind a hamstring strain injury. To monitor this parameter a new system is developed; the Smart Sensor Shorts. The system contains five Inertial Measurement Units (IMUs) integrated in a sports tights. The purpose of this study was to develop a methodology to estimate the muscle strain and muscle elongation velocity of the biceps femoris (BF), semimembranosus (SM) and the semitendinosus (ST) muscle in professional and recreational football athletes with the use of IMUs during different football specific movements and during different intensities. When comparing different movements and intensities, the greatest peak muscle strain was found in the BF and the lowest peak muscle strain was found in the SM during the majority of the movements. The biomechanical load was different for each hamstring muscle and was different for the running based movements and other football specific movements. The BF experienced the greatest peak muscle strain (12.12 ± 0.88%) during a maximal intensity kick in the supporting leg, while the greatest peak muscle elongation velocity was observed in the ST (3.97 ± 0.47 s-1) in the kicking leg during the maximal intensity kick. The greatest biomechanical loading was during a maximal intensity kick. Finally, it was observed that the moment of peak muscle strain was different from the time period of peak muscle elongation velocity for running based movements. It is concluded that IMUs together with the developed methodology could be used in the assessment of hamstring strain injuries in professional and recreational football by analyzing and monitoring muscle strain and muscle elongation velocity.

This project is an initiative of the Department of Surgery in Maasstad Ziekenhuis. In the department, two types of patients undergo abdominal surgery: 1) mobile obese patients and, 2) patients with cancer. These types of patients need personal contact and guidance, especially patients with cancer. However, nurses are overwhelmed with work and utilize a great amount of their time to manually measure the vital signs of patients three times a day. These vital signs are heart rate, blood oxygen level, respiration rate, tympanic temperature, and blood pressure. The current method of measuring vital signs is highly inefficient and prone to error. Additionally, there is also a lack of an alarming system that can notify nurses when patients’ health condition deteriorates. Due to this, patient deterioration cannot be detected in time and complications cannot be avoided. When manual measurement of vital signs is digitalized, patients can be continuously monitored. Due to this, small changes in the patient’s health condition can
be detected and nurses can intervene immediately. Current wearable devices in the market do not meet the needs and wishes of the user group. Therefore, the initial goal was to design a wearable device that is able to continuously and noninvasively measure vital signs of patients, taking into account the level of comfort for patients and level of user-friendliness for nurses. After extensive research, conceptualization, and testing, one final proposal is presented: Omnivisi Earable, a compact and lightweight wearable device that can measure all aforementioned vital signs in a continuous and non-invasive way. Due to its small form, it does not limit patients from performing their daily activities. It is also user-friendly for nurses due to the lack of wires and extra modules. This makes it easy for nurses to attach the product on the patient's body.

In the Netherlands alone, an estimated 730,000 persons are currently diagnosed with coronary heart disease (CHD), 120,000 with heart failure, and 260,000 with atrial fibrillation. As of 2014, cardiovascular disease accounted for 27% of all deaths1. The cardiology department of the Leiden University Medical Centre (LUMC) has a regional role in treating patients with different cardiovascular diseases, ranging from myocardial infarction, heart failure and infectious cardiac diseases to life support with left ventricular assist devices (LVAD) in severe heart failure patients. Coronary artery disease (CAD) affects a big proportion of these patients. Forty myocardial infarction (MI) patients are seen on a weekly basis in the outpatient clinic (MISSION!-clinic) at set times after the infarction event; 1 month, 3 months, 6 months or 12 months.

In an attempt to improve patient outcome, provide a better service and reduce the workload at the outpatient clinic, the LUMC launched a novel project called "the BOX". The BOX allows patients to self-monitor their vitals after a myocardial infarction (MI) or heart surgery, thus reducing visits to the hospital.

Patients are given a Wi-Fi scale, a watch with a pedometer, a Wi-Fi blood pressure meter (BPM) and a one-lead EKG/ECG monitor. The devices are produced by two different companies (Nokia/Withings and Alivecor) and are connected to the mobile phone of the patients. Patients have to measure their vitals on a daily basis and are instructed to contact a professional in case of emergency. Preliminary results show a good acceptance from the patients and high willingness to self-monitor their disease. This new product-service reduces the number of regular visits to the outpatient clinic by 40%, which are replaced by video conference.

In this context, the cardiology department plans to take the next steps to expand this service and provide effective and quality care using e-Health medical devices. Nevertheless, they are dependent on different stakeholders to do so. On the one hand, the companies that sell the medical devices (like the ones included in the BOX) control the patient data, and grant access to the hospital. A change in their business model can affect patient safety, privacy and the systems that the hospital has to put into place. On the other hand the patient must use the devices. Self-monitoring is an important behaviour for self-management, required for various chronic illnesses such as diabetes, hypertension, and heart diseases. But, having a plethora of devices and applications is not accessible for all the patients, which is a critical requirement for the LUMC as a part of a public institution that focuses on providing healthcare services to the general population. Moreover, a hospital requires stability for the long-term in order to implement technological solutions that directly affect patients.

The described situation is an interesting opportunity to look at product/services through different lenses (public sector) and design within the institution. Although, it also has the constraint/limitation that doctors are not engineers/producers. In addition, it is a vast problem to tackle, thus the necessity to focus on one area as the research is done.

This research provide a proof of principle to use a sweat sensor system for real-time monitoring of medicine effectiveness in Cystic Fibrosis (CF) patients. CF is an autosomal recessive genetic disorder affecting mostly the respiratory, digestive and perspiration system. Patients with CF have dysfunctional chloride channels in their cells, due to mutations in both copies of the gene for the CFTR protein. The CFTR proteins are necessary for the production of mucus, a malfunction of the CFTR protein will result in tough mucus. In CF, a lack of functional CFTR prevents normal sodium and chloride absorption in sweat and leads to excessive salt loss. Due to increased sodium and chloride concentration in sweat from CF patients, sweat makes a good clinical body fluid to indicate the medicines' effectiveness. By measuring the chloride or sodium concentration before treatment with the medicine and after treatment, an indication of the medicines’ effectiveness can be obtained. In this study, a potentiometric screen-printed sweat sensor has been developed to monitor the medicine effectiveness in CF patients. The sensor consists of a reference electrode and ion-selective electrodes for measurements of chloride and sodium concentrations. Multiple prototypes of the sensor have been developed and evaluated on their performance. Furthermore, a read-out circuit with low leakage/bias currents and 8 channels is designed to increase the read-out accuracy and speed. Since the sweat volume during rest appeared to be too low for real-time measurements, a sweat collector was implemented with the sensor to increase the sweat sample volume during real-time measurements. Furthermore, a pilocarpine sweat stimulator has been designed and tested to artificially increase the sweat rate.
The developed system proofed to be a functional concept for real-time patient monitoring. In future research, the chemical structure of the membranes is the most important topic to be improved. Improvements in this field could extend the life-time of the sensor and would minimise the sensitivity differences between the sensors. Finally, the sweat sensor, collector and stimulator have to be integrated and minimised in one design to make a wearable device out of it.

Alkaline water electrolysis will become increasingly important for supplying the world with sufficient renewable energy, and with raw material for the chemical and pharmaceutical industry. Zero Emission Fuels B.V. (ZEF), a technology start-up based in the Netherlands, is developing a small scale alkaline electrolysis cell (AEC), which is integrated in a methanol producing micro-plant. The challenge of this project is to look into the use of polymers for the encapsulation of the ZEF AEC. The conditions of the ZEF AEC are not to be neglected. The system will run in a 30wt% KOH solution at a temperature of 90 °C and a pressure of 50 bar. Not many polymers will be able to withstand these conditions for a desired lifetime of 20 years. Using CES EduPack, a selection of 30 potentially suitable polymers has been made, from which high density polyethylene (HDPE), 40% glass-reinforced polyphenylene sulfide (PPS-40%gf) and polysulfone (PSU) are further investigated. Based on a literature review and a simple KOH ageing test, HDPE is found unsuitable for application in the ZEF AEC. PPS-40%gf and PSU have been subjected to durability testing for a range of different conditions involving a variety of KOH concentrations (15, 30 and 45wt%), and two oxygen partial pressures (O2 at 5 bar and air with pO2=20%) at different temperatures (90, 120 and 170 °C). The purpose of the ageing experiments is to give a better understanding of the effect of these parameters on the structure and integrity of the polymer; and to eventually be able to acquire a lifetime prediction. Extensive characterisation of the exposed samples has been carried out using different techniques, including weight measurement, tensile testing, DMA, creep-recovery testing, DSC, FTIR, XRD and SEM. After 12 weeks of ageing, it is found that glass-filled polymers are unsuitable for application in a strong alkaline solution at elevated temperatures, due to the dissolution of the glass fibres, which leads to a reduction in mechanical and barrier properties. However, the PPS matrix and PSU are found to be resistant to thermo-oxidative and chemical degradation in the tested ageing conditions. Only subtle changes in mechanical, visco-elastic and thermal behaviour are observed, which can be assigned to the effects of physical ageing. Due to the undesirable brittle nature of PPS, it can be concluded that PSU is the most promising candidate for the long-term application in alkaline electrolysis.

Female sterilisation is difficult to access in many low- and middle-income countries. Opt Medical wants to solve this problem by developing a clip that can be placed around the Fallopian tubes during C-sections without immediately affecting the fertility. By activating the clip at a suitable time, a clamping mechanism occludes the Fallopian tube leading to scar tissue formation and eventually sterility. This requires the development of a Nitinol clamping mechanism as described in this study. Part 1 contains a study on the shaping and training of Nitinol, part 2 describes the development of a simple and affordable way to test the clamping force and part 3 focuses on the iterative design process of the Nitinol clamping mechanism.

The prosthetic eye is created to help people who have lost an eye. The eye itself can only improve the appearance but without any optic function. In order to optimize the appearance, a prosthetic eye with a pupil that can dilate and contract according to the light level, just like the natural eye, is desired. The primary goal of this work is to develop and characterize a dilating pupil based on electrowetting. A droplet of an aqueous solution acts as a pupil.
Electrowetting-on-dielectric (EWOD) has become one of the most popular tools in variety of applications, from microfluidics to electrowetting displays. This thesis presents the design of a low-voltage electrowetting one-pixel display which can act as a pupil. Decreasing the maximum actuation voltage is the main objective and challenge of this project. Different methods to achieve this goal are presented in the thesis, including using dielectric materials with better dielectric properties and using electrowetting liquids with lower surface tension. Ways to minimize the effect of gravity are also investigated. Droplet-based simulations are introduced by two methods. The simulation results are used to sustain the design process and for comparison with the measurement results on the real devices. According to the theoretical background and simulations, a test device is designed and fabricated in the cleanroom of EKL, TU Delft. The fabrication details are described in this thesis. Finally, measurements on the fabricated device are performed under different conditions. The results are shown and discussed in the final conclusions. In general it can be said that an electronic dilating pupil based on EWOD seems possible. Some recommendations for the future improvement are made.

This thesis describes the process of redesigning the 3D-paintbrush. It looks into extruder screws for plastics and finds the best design variables for the 3D-paintbrush. Vortex cooling has been used to cool the extruded plastics fast and efficient. With the findings for melting and cooling the thesis looks at human-machine interaction and combines these findings into a final redesign. A mockup is made of the redesign to validate the interaction between the user and the 3D-paintbrush

Post Traumatic Stress Disorder (PTSD) is a psychiatric diagnosis that describes an unusually long stress reaction of at least a month to a traumatic event where a person was threatened by or indirectly exposed to death or serious injury. This stress reaction includes persistent re-experiencing (nightmares, flashbacks, memories), changes in arousal (hyper-vigilance or self-destructive behavior), persistent avoidance of trauma related stimuli and negative emotional state. It is estimated that around 4% of Dutch veterans suffer from PTSD.
There are currently two therapies that have been researched enough to proclaim an effectiveness of around 70 percent: Cognitive Behavioral Therapy (CBT) and Eye Movement Desensitization and Reprocessing (EMDR). But they can be very hard to complete and it still leaves around 30 percent behind. Furthermore, this type of research often excludes more difficult cases with co-morbidity. For them the focus is often more on stabilization and symptom reduction. One of the ways that symptom reduction is attempted, is by teaching relaxation exercises, including breathing techniques.
It is envisioned that a veteran with PTSD can always have a product with him that, in a way, understands him and can physically respond. A product that can distract when it senses a distressing flashback/intrusion, can physically help to calm down when needed and communicate how the veteran is doing.
Research into existing projects and products showed there are already many products that can detect rising stress level. They can give some type of feedback. Some give a warning with audio or some vibration. Others show how to breathe calmer with tones or a visual bar or graph. But none give a strong physical stimuli to calm down.
A promising way to distract and calm down in an unobtrusive, yet strong way, is alternating pressure around the abdominal area. It can help calm down by inducing calmer and deeper breathing, comforting pressure, distract when needed (bring attention back to the present), and communicate about stress levels.
A first user test indicates that pressure can distract and induce slower breathing. But a test setup that can be controlled more precisely is needed to make a definitive conclusion.
Using solid state actuators to generate this pressure turned out to be problematic. Although they have the advantage of being very compact and silent, the actuators that could generate enough force - nylon supercoiled polymer and nitinol - turned out to require a high temperature for actuation (>70°C) and also needed significant bias force to move back to the original position. This severely limits their use in a product around the body, requiring significant isolation material and restrictions on the actuation time. They are also very inefficient, 95%, is lost as heat. Therefore they require a larger power source.
Using conventional electro motors provides significant challenges. They are very efficient and can be made inaudible to the human ear, but this is only done for application where it is absolutely necessary. There is no standard solution available for generating a high force in a large but very thin package that is inaudible to the human ear. Getting to an acceptable size will provide a significant challenge. Using an electro motor does seem more promising than a solid state actuator, especially for building a prototype that can be used to test the effect.
The embodiment for the concept is a ‘belt’ that can be worn around the abdominal area. Three prototypes were built. The first was mainly to show the concept, with a simple cheap servo motor, a sensor to detect breathing and pressure sensors for communication. The second prototype used large flat silent stepper motors, but because of several problems it did not work properly. The last prototype contains a somewhat oversized DC motor, to be sure that it will deliver enough force to test the basic effect.
The basic effect was tested with prototype 3, with 8 students from the TU-Delft. Most participants found it calming and comfortable. Some found it constricting and unpleasant. Most adapted their rhythm and were distracted from their thoughts. More research should be done to further develop and verify this.
A design proposal shows what the eventual product can look like and gives direction to further development.

Electroluminescence is light emission of phosphor when it is placed in a strong electric field. This field is created by placing a dielectric (non conductive) layer between two electrodes. The field strength is affected by the voltage, distance between electrodes and the dielectric properties of the dielectric layer.
Current do-it-yourself (DIY) solutions for the creation of electroluminescent panels require more than two hours for the creation of a custom design and have a significant chance of failure. These factors make it an unappealing material to work with.
In order to make this material more appealing to design student the goal of this project is to develop an easier construction method for DIY electroluminescent panels. A method that takes less time and has a high success rate, with similar result as existing construction methods.
Through the exploration of multiple methods for constructing EL devices a solution is found.
Combining phosphor powder with UV curable adhesive creates an mixture that can cure in a matter of seconds. This mixture can be spread across a piece of vinyl, placed on an electrode and with a cut-out of the required design. When placed underneath UV light, oxygen inhibition prevents the outer layer of the mixture to cure. The second electrode can now be attached and after a final curing process the panel is ready to use.
Extensive user testing has shown that this method will take less than 15 minutes and has an high success rate.

Reliability is one of the major research topics of modern electronic packaging technology. The characterization of Au-Sn dia-attach solder material properties, including viscoplastic properties is requested for fast and accurate reliability assessment by industry. In this thesis, a detailed experimental based methodology to characterize Au-Sn solder's viscoplastic properties, including raw material introduction, test specimen preparation, shear creep experiments and test data analyze is provided. Furthermore, a study of microstructure effect on Au-Sn solder viscoplastic performance by experiments and following reliability analysis is presented.