This report is part of a bigger project to design a fall detection system for elderly and describes the hardware of the system. The importance of this research is that elderly can live longer in their home by alerting the correct instances in case of an accident. The hardware consists of a 1x2 meter sensor grid below the surface of the floor. The sensor grid uses the piezoresistivity of linqstat to measure the pressure and the location of the pressured point on the floor. An ESP8266 microprocessor combined with 74HC595 shift registers and a 74HC4067 demultiplexer is used to gather the data and send it to a server. The design is modular allowing easy installation in differently sized or shaped rooms. Each individual sensor grid has an update frequency of 14Hz and uses wifi to connect to a common server. Each module has an average power consumption of 0,74W and a peak power of 1,6W.

Nowadays, the society strongly depends on computer networks and systems as a means of reliable communication and data storage. In order to maintain absolute security of the networks and thus the society, one would need to separate everything, but this is not feasible. Consequently, sharing of resources is inevitable. There are security products that rely on an FPGA to create domain separation. The domain separation is required to prevent leakage of confidential information and manipulating of critical processes. A modern FPGA has enough resources to have multiple soft-cores initiated on it- each of them working in a different domain. However, due to the limited amount of IO pins on an FPGA, using multiple DRAM chips is not an option. Therefore a single DRAM is shared between multiple soft-cores, threatening the domain separation. The main threats when using a shared DRAM are communication channels due to latency deviations, data corruption due to rowhammering and direct access to unauthorized data due to the data being available on shared addresses. Research has been done to determine what causes the latency deviation and how to mitigate it. The results of the research are that the only fundamental solution to mitigate the latency deviation is to have a fixed latency when accessing the DRAM. A fixed time arbiter is designed and tested. The fixed time arbiter is using a deterministic delay after each DRAM access in order to mitigate the latency deviation. Before mitigating the rowhammer vulnerability it is shown that rowhammering causes bitflips not only in the adjacent rows, but also in non-adjacent rows. To mitigate the rowhammer vulnerability for adjacent rows, a row refresher is created that tracks the rows that are accessed and refreshes the adjacent rows when accessed more than the bitflip threshold. To mitigate the vulnerability for non adjacent rows a test is created to give an overview of all non adjacent rows that contain bitflips so that those rows can be be dedicated as unused guard rows. The last part that is implemented is an address mapper to be sure that no soft-core can access the addresses of another soft-core. The fixed time arbiter, row refresher and address mapper are combined into the memory domain protector. The consequence on the bandwidth of the DRAM is that the bandwidth is halved compared to the benchmark design. The memory domain protector also uses 23× more logic than a standard arbiter.