This report presents a proof-of-concept for a sensor measuring the ionic concentrations in sweat using cyclic voltammetry. Development is focused on feasibility of the sensor. Theoretical evaluations of voltammetry as a working principle and its physical and electrochemical foundations are guiding principles of the design. The sensor is then implemented using commercial components. Experiments show that the sensor has good sensitivity and linearity for single ions in the physiological range. For the measurement of multiple ions the voltammogram is characterized in-depth. A matrix of different ionic fluids with multiple ions is prepared and two independent parameters for the concentration of two ions (sodium and potassium) are found, proving the concept of the sensor for more complex solutions. The usability of the sensor is verified using a sweat sample. Different influencing factors are researched and their impact characterized. Varying electrode materials are evaluated considering durability and sensitivity. Conclusions are drawn and an outlook for future research on this type of sensor is given. The concept of the sensor is proven to work within certain limitations.

Over the years, care givers in nursing homes have seen their workload gradually increase. With no end of this trend in sight, the need for smart support systems increases. Especially systems which decrease the time spent on menial tasks are valued highly, because this frees more time for high quality and personal care.
To achieve this, Momo Medical is expanding on its nurse support system. This is a network of integrated smart solutions aiming at supporting care givers in nursing homes to provide better, faster and more personal care. The backbone of this nurse support system consists of the BedSenses, sensors which are placed under mattresses of each resident and can measure a variety of things.
This thesis describes the process of designing and creating a localization algorithm for this nurse support system. This algorithm can find residents by tracking the panic buttons they wear, so that in case of an emer- gency or whenever a care giver wants to know where a resident is located, they do not need to undertake a time consuming search in order to find them. These panic buttons send out an alive signal once every minute as well as a signal whenever the button is pressed. These signals are received by any nearby BedSenses. The algorithm looks at the signal strength with which each BedSense receives these signals and uses this to per- form localization.

To make open door policies easier in nursing homes, it is important to have a smart system that can check whether access is allowed for the person trying to enter some place or not. This thesis documents how an access control system has been built, for Momo Medical, to be used at a nursing home. It sheds light on hardware considerations made and the software written for the final product. All the knowledge gathered and the time spent has led to a final product that with minor tweaks can be used in the existing infrastructure of Momo Medical but also without the presence of it. There are however still improvements left to be made for the final product to be commercially appealing.

Laryngectomised people (LP) have many problems with speaking in terms of intelligibility, volume and effort it takes. This thesis describes the design and simulation of a voice enhancement device which will improve the speech of LP with respect to intelligibility and volume. It only describes the chosen hardware peripherals in order to record, process, amplify, and output the modified speech.
The recorded audio could be processed using a digital signal processor (DSP) that could be programmed such that it will filter the undesired noise and shift the pitch of the speaker's voice in real-time.
This thesis focuses on the real-time pitch shifting of the voice, the hardware choices and implementation of the sound output of the system, and the implementation of DSP of the Tracheo-Esophageal Speech Signal Amplifier (TESSA).
The real-time pitch shifting makes use of the Ocean algorithm, of which the principle is described, implemented and tested. Intelligibility tests are performed in order to find the optimal shifting parameters.

In the last 4 decades, surface electromyography (sEMG) signal processing has been applied to detect local muscle fatigue, this non-invasive approach is suitable for detecting EMG signals generated by athletes in motion. Also, EMG could directly reveal the muscle’s performance like endurance and recruitment of motor units, which is hard to be obtained by other methods. With the sEMG system, we can research whether EMG signals can be used to measure muscle fatigue and how this relates to injury risk. This thesis aims to build a sensor node for sEMG to detect local muscle fatigue. An sEMG system is built for this purpose, and a physiological experiment is designed to collect sEMG signals from human muscle (Vastus Medialis) using the sEMG system. Both isometric and isotonic exercises are studied. The data analyzing method is calculating mean power spectrum frequency (MNF), median power spectrum frequency (MDF), and muscle fiber propagation velocity (MFPV) of the collected sEMG signals, because local muscle fatigue is related to MNF/MDF decrease and MFPV decrease. 5 groups of isometric exercise, wall-sit and 2 groups of isotonic exercise, cycling, are recorded. All the athletes are healthy males, around 25. The data analyzing result shows that MNF/MDF decrease is related to muscle fatigue, and MFPV changes similarly with MNF/MDF.

This BSc Thesis is about the construction and control elements of the airplane group of the Solar Drone project. The project aims to improve the flight time of aerial vehicles, using solar energy. This document is delves into the possibility of applying solar cells to small model aircrafts. It outlines the challenges and solutions involved in building and controlling such a system. A ready-available airframe and fitting components will be used, in combination with a custom photo-voltaic and energy system, to create a prototype. The prototype takes the form of an unmanned aerial vehicle, making it capable of extended flights without requiring extensive monitoring. It will serve as a testing platform for the performance of the PV modifications done to the aircraft.

Included in this document are simulations for calculating optimal solar panel placement inside a transparent wing with opaque ribs, in addition to software and hardware modifications that were required to make the other systems work well in combination with the custom energy system.

An extraction channel cleaning company wanted a grease thickness sensor to be developed that would send the data via the internet so that information on the thickness could be accessed remotely. This system consists of two parts: the sensor part and a communications part. This report is on the sensor part, which uses a change in capacitance of an interdigital capacitor, which in turn will change the frequency of the oscillator readout circuit. Initially research was done on the properties of grease to see if it would be a good method to measure the thickness. The results showed that it is possible to use capacitance, but that the permittivity of grease depends on the temperature, so the final design needs a temperature sensor. The prototype that was built was used to measure thicknesses and had quite reasonable results.

The goal of this project is to identify the most promising measurement method and strategy for measuring the thickness of grease and to design a sensor module with electronic read-out and communication module. This project has been split into two parts: a sensor implementation and a communication system. This report describes the design and implementation of the communication module and power supply. The communication module has been designed to work conform a master-slave principle using MODBUS over an RS-485 databus. The used hardware for the communication module is rated to work within a desired 1 to 100m range. Furthermore the master node is connected to the internet to present the data on a small webserver. The power supply design depends on the implementation of the sensor, and contains the use of linear voltage regulators and inverters. The results show that the communication module works properly, whereas the power supply requires some further work.

The cleaning company "VETkanaal" requested a sensor system that measures the thickness of a grease layer within kitchen extraction ducts independently and is able to send this to an online platform. The goal of this project is to find an acoustic implementation of the sensor and be able to apply it. It appeared that measuring a shift in resonance frequencies of a plate with varying amounts of grease is the best solution for estimating the thickness of a grease layer. Afterwards, a hardware implementation was made. The conclusion of this report is that an acoustic measuring principle is certainly possible. The first tests of trying to implement such a system were moderately successful.

Internet of things (IoT) applications become more and more prominent in our modern society. IoT has the potential to improve business processes and change the ways we live. KPN New Business has a high affinity with IoT projects and supplied the problem definition that this project builds on. The project has been done in close collaboration with KPN.

This document describes the design process for a stand-alone obstruction detection system for supermarket environments. The focus lies on obstructions near emergency exits, where they pose safety threats and obstructions in shopping aisle, where they hinder customers. The system should detect obstructions and communicate the presence of an obstruction to a central server. The communication is however not within the scope of this design report.

Five sensing techniques were considered for the detection system, ultrasonic ranging sensor were deemed the most suitable for this application. Ultrasonic sensors lend themselves well for IoT applications as they are easy to implement, cheap and operate on low power.

A MaxBotix MB1300 sensor was chosen for the implementation of the prototype as it offers an Analog Envelope (AE) output of the measurements. This allows for multiple objects to be detected in a single measurement. Furthermore, the MB1300 sensor has the largest beam width in the AE product line and can thus cover the most surface area.

The processing of the measurements in the prototype is done using an Arduino Mega 2560. The Arduino board allows for easy prototyping and has sufficient memory on-board to store and process the measurements. The measurements are sampled using the built-in ADC of the Arduino at a sampling frequency of approximately 8.93 kHz. The sampling frequency is a trade-off between the spatial resolution of the system and the memory required to store the measurements.

An algorithm is developed for the detection of objects from the sampled measurements. The process involves the windowing of the measurements to only look at relevant samples. A background subtraction is performed to avoid the detection of scenic objects, and the objects are detected using a threshold.

A data structure was created in order to store the detected objects. An algorithm was developed to check whether detected objects remain static. If an object is repeatedly detected it is marked as an obstruction. If an object goes unseen for a certain period, the object is removed from the memory. Thresholds for when an object is marked as an obstructions, the deletion of objects and measurement intervals are suggested for emergency exits and shopping aisle systems. These should however be verified in further development.

The performance of the system was evaluated in testing environments for the emergency exits and shopping aisles. Testing results showed that the system performs well on most design criteria. The area covered by a single sensor was however below expectations. This could be problematic for the implementation of the system in shopping aisles, as lots of sensors would be required to cover entire shopping aisles. Also some false positives occurred in the detection of obstructions. This could however easily be solved with minor changes to the detection algorithm.

Based on the testing results the conclusion is drawn that the design goals are partially met. The system is able to detect obstructions, but does not yet operate as a stand-alone unit. This design goal was however considered in every design choice. Power consumption of the prototype remains to be tested, this however is also dependant on the communication system.

Recommended is to further look into the power consumption of the system, the implementation of a multi-sensor system to cover more floor area in shopping aisles, and to reconsider CCTV images for the detection of obstructions in shopping aisles.