his thesis focuses on optimization of Linux-based operating system for a accumulator-powered device Raspberry Pi 4. Compared to other devices commonly used in Internet of Things projects, the Raspberry Pi 4 offers many functions within one device. However, the disadvantage is the high consumption of electricity. The aim of this thesis is to achieve greatest possible savings in electricity consumption of the Raspberry Pi 4 device, with regard to functionality of the device as a server for data collection from sensors.

The number of discovered vulnerabilities rapidly increases. For example in 2019 there were discovered 20 362 vulnerabilities. The probability of cyber-attacks realization is high. Therefore it is necessary to propose and implement automated and low-cost Intrusion Prevention or Intrusion Detection Systems (IPS/IDS). This implemetation can focus on home use or small corporate networks. The main goal of the system is to detect or mitigate cyber-attack impact as fast as possible. The master's thesis proposes IPS/IDS based on Raspberry Pi that can detect and prevent various cyber-attacks. Contents of this thesis are focus on description of cyber-attacks based on ISO/OSI model's Link and Network layers. Then there is description of IPS/IDS systems and theirs open source representatives. The practical part is focus on experimental workspace, hardware consumption of choosen detection systems, cyber-attacks scenarios and own implementation of detection program. Detection program is based on these chosen systems and puts them together to be easily manageable.

En kostnadseffektiv, liten robotbil som är fjärrstyrd via Wi-Fi harutformats och testats för att möjliggöra inspektion och identifiering avpotentiella faror vid olycksplatser. Robotbilenär avsedd att användasför rekognosering och inspektion och kan bidra till att utforma enadekvat insatsplan. Hjulupphängning och hjul konstruerades medhjälp av en 3D-skrivare. Den färdiga robotbilen är utrustad medmikrokontrollern Raspberry Pi som har flera funktioner som gör denanvändbar i olika scenarier. Det finns en kamera som möjliggörfjärrinspektion av bilens omgivning. Utöver kameran finns det tresensorer som är kopplade till Raspberry Pi-enheten, nämligen engassensor för att upptäcka farliga gaser, en ultraljudssensor för attmäta avståndet till närmaste objekt och en temperatursensor för attmäta omgivningstemperaturen. Robotbilen använder enmotorstyrningsmodul för att styra bilens rörelse och två servomotorerför att möjliggöra att rotera kameran i vertikal och horisontell led.Robotbilens strömförsörjning kommer från ett batteri och tvåspänningsomvandlare används för att reglera spänningen tillmotorstyrningsmodulen och Raspberry Pi-enheten. Genom attintegrera dessa komponenter i en enda enhet och programmeraRaspberry Pi-enheten för att styra dem, kan robotbilen effektivt hjälpaatt undersöka och hantera potentiella faror. / A cost-effective small robot car that is remote-controlled via Wi-Fi hasbeen designed and tested for inspecting and identifying potentialhazards at accident sites. The robot car is intended for reconnaissanceand inspection purposes and can contribute to formulating anadequate action plan. Wheel suspension and wheels were constructedusing a 3D printer. The finished robot car is equipped with theRaspberry Pi microcontroller, which has severalfeatures that make ituseful in various scenarios. There is a camera that allows remoteinspection of the car's surroundings. In addition to the camera, thereare three sensors connected to the Raspberry Pi unit: a gas sensor todetect dangerous gases, an ultrasonic sensor to measure the distanceto the nearest object, and a temperature sensor to measure theambient temperature. The robot car uses a motor control module tocontrol its movement and two servo motors to enable the rotation ofthe camera in the vertical and horizontal directions. The robot car ispowered by a battery, and two voltage converters are used to regulatethe voltage to the motor control module and the Raspberry Pi unit. Byintegrating these components into a single unit and programming theRaspberry Pi unit to control them, the robot car can effectively assistin investigating and managing potential hazards.

A mesh network is a technology that is being repopularized and becoming commonly used by the general public. As this increase in use is observed, technologies such as Bluetooth are being adapted to create mesh variants. In this thesis, a Bluetooth mesh network is created and tested using raspberry pi 4’s and the Bluetooth interface, btferret. This thesis attempts to approach the limits of this technology using accessible tools, outlining the performance the network possesses to serve as a guideline to determine if it suitable for use for tasks at hand. Experimentation is split into two overarching methods where a test for latency and throughput is conducted. The thesis goes on to expose these tests to different stressors, categorized as either internal or external. The data collected aims to show the impacts of internal properties, in this case size of the packets transmitted, the size of the network, and finally the number of hops a packet is able to make within the network. The external factors tested for consists of various environmental properties in the form of obstacles and interference. Walls and a microwaves were used as obstacles while WiFi and other Bluetooth signals were used for interference. The results show that Bluetooth Low Energy (BLE) mesh networks are clearly affected by several internal and external factors. From the experimentation conducted, the thesis illustrates the relative effects of each property the tests are exposed to. / Ett mesh nätverk är en teknik som blivit populär igen och används ofta av allmänheten. Eftersom denna ökade användning observeras, tekniker som Bluetooth anpassas för att skapa mesh nätverksvarianter. I denna avhandling skapas och testas ett Bluetoothnätverk med Raspberry pi 4’s och Bluetoothgränssnittet, btferret. Denna uppsats försöker nå gränserna för denna teknik med hjälp av tillgängliga verktyg, definiera nätverks prestandan som en riktlinje för att avgöra om det är lämpligt för användning för uppgifter till hands. Resultaten visar att BLE mesh nätverk har tydliga begränsningar som avslöjar sig i olika sammanhang. I denna raport så undersöks paket storlek och antal hopp som ett paket kan göra inom nätverket utan signifikant prestandafall. Dessutom har olika andra faktorer, såsom väggar och andra störande radiofrekvenser visat sig påverka nätverket. Från alla experiment som genomförts så illustreras relativa effekt av det olika faktorer.

Automatic Passenger Counting (APC) systems are some of the many Internet-Of-Things (IoT) applications and have been increasingly adopted by public transportation companies in recent years. APCs provide valuable data that can be used to give an real time passenger count, which can be a convenient service and allow customers to plan their travels accordingly. The provided data is also valuable for resource streamlining and planning, which potentially increases revenues for the public transportation companies. This thesis briefly studies and evaluates different APC technologies, highlights the advantages and disadvantages of these, and presents an Edge-prototype based on Computer Vision and Object Detection. The presented APC was tested in a lab environment and with recordings of people walking in and out of a designated area in the lab. Test results from the lab environment show that the presented low-cost APC efficiently detects passengers with an accuracy of 98.6% on pre-recorded videos. The APC was also tested in real time and the results show that the low-cost APC only achieved an accuracy of 66.7%. This work has laid the ground for further development and testing in a public transport environment.