This report describes the design and implementation of a sensor-based proximity sensing system implemented to assist the camera-based system. The goal of the sensor-based system is to provide a potential alternative to the camera-based system, and also to compensate for any of the downsides of this system, such as relatively worse performance in low visibility conditions, gauging distances accurately and implementing a collision warning mechanism. This will be done through the use of ultrasonic sensors. The sensor considerations and sensor
network will be described in depth. Furthermore, analysis of numerous signal processing techniques will be performed. These techniques will differentiate objects based on their respective echoes, which allows for accurate mapping onto the user interface, once the locations of the objects have been obtained through 3D trilateration. The prototype implementation along with the system integration with the camera-based system will be discussed once all of the previous work is done. Afterwards, the results of the project will be discussed and the work will be concluded with some future recommendations.

The leisure vehicle industry has long trailed the main automotive sector in regards to driver assistance technologies, despite one-sided accidents at low speed being a common occurrence in the industry. This thesis describes the process of designing a wireless 360° camera sensing system in an attempt to catch up this leisure vehicle market to present automotive technology. Such systems can be found in many modern vehicles, however these systems are all wired implementations with there being no need for a wireless solution. The design emphasizes quick and straightforward calibration to facilitate usage as an aftermarket product. A prototype is built using Raspberry Pi's to demonstrate the feasibility of the design. This paper also presents research on possible further improvements of the designed system, and it presents a concept of a composite system through integration with a proximity sensing system.

Practicing fire scenarios in emergency response training is very hard due to various obstacles. An example is when holding a training, real fire will preferably not be used as it can become threatening. Real fire will only be used in a surrounding where safety is ensured, which is probably outdoors. An emergency responder hardly knows that it has entered an area or room with imaginary fire nor does he know the extent of the fire due to the absence of smoke. This makes it exceedingly difficult to make right decisions during the training on the spot and this might lead to failure to help employees or clients to escape the fire area or building. This project focuses on developing glasses that can darken the view of the user, when entering an area with simulated fire and smoke. In order for the emergency responder to be able to practice in the most real possible scenario. The gain of using the glasses, is that it provides a common understanding between the instructor and trainee about the smoke situation in a training exercise. This enhances the quality of training, decreasing the possibility of making an incorrect decision when a real fire breaks out. This is done by constructing a set of darkening glasses that can darken the view, on the command of an infrared beacon that mimic the source of smoke in an area.

In football, most of the injuries occur in the lower extremities of the athletes. The leading cause of this is high muscle stress during explosive actions. To be able to prevent injuries, the Dutch Football Association (KNVB) and Dutch Hockey Association (KNHB) are working on smart sensor shorts in collaboration with the Delft University of Technology. The human movement scientists from the VU and RUG use these sensor shorts to develop a model which can predict potential incidents. The product’s goal is for the physical trainer to use it to monitor the team in real-time during a game or training.
The physical trainer will use a computer to analyze all the data. The sensor shorts consist of 3 Inertial Measurement Units (IMUs). Each IMU measures the angular velocity (dps), linear acceleration (g), and magnetic field (µT) with a ampling rate of 250 Hz. The high volume of data due to the high sampling rate induces challenges for wireless communication and design.
The sensor shorts can, at the moment, read out the IMUs and compress the sensor data. Besides, possible antennas for the sensor shorts have already been looked at. This thesis will continue with the communication link between the sensor shorts and the computer used by the physical trainer. The thesis will be focused on designing a reliable system for wireless communication. Multiple challenges must be faced to develop a reliable wireless communication system with minimal size. The challenges are the minimum amount of resources available, high data rate, large area to cover for communication, and obstruction due to the human body.
According to literature about monitoring devices currently described in the literature used for football, eight base stations are needed around the football field. The goal is to minimize the number of base stations so that the system can be easily set up. For the development of the system, first, the different Data Collection Protocols(DCP) are examined. Based on the network topology corresponding to the DCP, we want to choose a DCP that is the most efficient and reliable. The Direct Delivery protocol was chosen as most suited in combination with WiFi operating at 2.4 GHz. WiFi can deal with the high data rates and communicate over large distances.
The number of base stations needed is determined based on tests performed on the football field. The choice was made to place the antenna of the sensor shorts on the back of the athlete because there it has the most negligible chance of obstruction due to the athlete’s limbs. The athlete’s own body could cause attenuation of 10 dBm. Additionally, it was chosen to have the base station at 2.2 m height, to have fewer chances of obstruction due to the athletes on the football field. Multiple tests have been performed to determine how many base stations are needed. First, the possible signal strength values of the sensor shorts around the football field have been measured for a single base station. After that, a relation between the measured signal strength and possible loss and delay has been established. These results made it clear that more than one base station is needed. In tests with two base stations, it became clear that data might get lost when there is no base station in the radiation plane of the patch antenna of the sensor shorts. Therefore the choice was made to have four base stations, one on each corner of the football field, so that there is always a base station in the radiation plane of the patch antenna. Based on the test results, the choice was made to have four base stations, one on each corner of the football field. Assuming that the sensor shorts’ RSSI values are always higher than −80 dBm, the system with four base stations would have a loss of less than 5%. The upper boundary for the delay would be 5 s.

Decreasing injuries in football is a topic of interest for the KNVB and KNHB. To reach this goal, the use of smart sensor pants is researched. The data will be used to develop models for finding injury risk factors that are related to movements. Currently, the system is capable of reading out the IMUs and storing the data on an SD-card, for post-analysis of the data. As next step, the communication link should be implemented, for real time feedback to the football players. The design of an efficient communication system in terms of power, size, and reliability, is quite a big task. By looking at similar research to body-worn devices, it is noted, that most devices deal with a 10 times lower data rate than the current device. On top of that, it is noted that the absorption of the body is causing problems on the link reliability. Based on these observations, it is decided to focus the research of this Thesis on the reduction of the data load, and the optimization of the transmission part of the smart sensor pants. The Thesis is split into two parts, the first part will show the use of lossless data compression. The second part will start with showing the benefit of using a patch antenna over a dipole antenna and continues by showing the benefit of using a dual antenna configuration over a single antenna configuration. To be more specific, the first part of this Thesis starts by comparing different lossless data compression algorithms, from which the FELACS algorithm is chosen as most suited. This algorithm is then implemented on the current hardware and tested on data from the smart sensor pants in a realistic football scenario. These results show an average compression ratio of 43 %-45 % in the most intensive 5-minutes of a football game, with a minimum of 38 % in an interval of 10 s. To improve the compression algorithm, an adjustment to the FELACS algorithm is proposed. This adjustment is theoretically tested and shown to outperform the FELACS algorithm with a higher compression ratio. In the second part, the use of a dual antenna configuration is discussed, whereby the use of a patch antenna is compared to a dipole antenna. It will be shown, that a dual antenna configuration can significantly improve the signal strength around the player, resulting in an almost isotropic radiation pattern, using pattern diversity. On top of that, this form of pattern diversity is observed to increase the reliability of the link, using switched combining. Moreover, it will be shown that a patch antenna will be more suited for this application, due to the higher gain in the front, and the robustness against interference when placed close to a conducting material. In summary, the two main contributions of this Thesis, are the reductions in data load, and the testing and verification of the dual patch antenna configuration. These contributions provide the basis for the communication part of the smart sensor pants.

Every year an unfortunate part of the population lose their larynx, often due to the consequences of cancer. The laryngectomy removes the possibility to speak. Fortunately several speech reinstatement techniques have been found. However, all current speech reinstatement techniques do not produce a lot of volume. As a result the laryngectomised person will have difficulties speaking in busy environments, up to the point were the condition can lead to isolation because of the inability to communicate. Moreover with the current methods it costs a lot of energy to speak, the produced speech is less stable and the fundamental frequency has become lower. In this thesis a device is designed to improve the speech produced by a laryngectomised person realtime. The speech is recorded with an electret microphone. The resulting signal is prepared to be quantified to then be processed by a digital signal processing unit. Then the signal is adaptively filtered using the dynamically determined fundamental frequency. By tracking the fundamental frequency some instability from the voice is removed. The fundamental frequency will be determined using the cepstrum, a technique separating the fundamental regency of a voice from the high frequency components added by the oral and nasal cavities during speech. In another thesis a system is designed to amplify the signal to make sure that speaking takes less energy \cite{shiftgroep}. Furthermore a suitable power source is determined for the system. As the system is designed for Tracheo-Esophageal Speech Signal Amplification, the system will be referred to as TESSA.

Clean drinking water is still not widely available around the globe and therefore remains an unsolved issue. In fact, 1 in 9 people lack daily access to safe water and sanitation. Groundwater is a water supply source that needs minor treatment and thereby presents itself as a good solution to this global issue. Especially in development countries for example in East Africa this would be a viable solution. One interesting exploration method to detect groundwater in an area is airborne Frequency Domain Electromagnetic (FDEM) survey. However, most airborne EM survey instruments are expensive and bulky. Even though that this exploration technique has been around since the 50s, a commercial inexpensive airborne FDEM instrument has still not penetrated the market. This thesis describes the investigation of a novel portable FDEM survey instrument that will be employed by an Unmanned Aerial Vehicle (UAV). The system architecture for the measurement instrument is presented and the functionality, design considerations and requirements of each system block is given. To check the feasibility of the proposed architecture, a handheld Proof-of-Concept is implemented, which can carry out measurements between 100 - 12.000 Hz. The experimental measurement results of the Proof-of-Concept at operating frequencies of 925, 2175, 5025 Hz are presented and compared against measurements of GEM-2A instrument, which is employed as a reference.

In this thesis, a test device is designed for the company Momo Medical. Momo Medical is developing a system that can be used to prevent pressure ulcers and adding more functionality is being investigated. For this system they need a device to test the functionality of the six piezoelectric sensors that are used in their product. The sensors’ response to a known pulse needs to be tested in order to give a pass/fail indication of the sensor quality. First, different ways of testing the sensors are investigated. Based on the results of the investigation, a final test setup is chosen and characterized. The test system developed in this thesis is based on a pneumatic setup, using a solenoid valve to control well-defined air pulses directed towards the sensors. Due to the addition of a reference load cell with custom designed read-out electronics, the device is able to test all six sensors one at the time and provides detailed feedback about the individual sensor quality. The test is performed using GUI-based software written in MATLAB, connected to a microcontroller. The software offers a broad variety of settings and can be configured according to Momo Medical’s wishes. After configuration, the test can be performed at the click of a button. The standard deviation of the device precision over three hours is sigma = 4.16, which equals a variation of cv = 0.82% of the mean μ = 504.8. This easily satisfies the requirements set byMomoMedical.