A risk we anticipate is that the power source circuit or the UPS hat does not work as we desired. For example, the voltage dropped too quickly that is not long enough for the rpi to execute its shut down process, or the circuit overheats because of the capacitor. To mitigate this risk, we could
Add more element in our circuit, for example a cooling device
Add a button connected to the rpi for the user to manually control the rpi to execute its shut down process
Changes
We originally planned to use DynamoDB for the web app backend since it’s easier to set up and works well for flexible data storage. But after thinking more about security, especially tracking access logs, we decided that a hybrid approach might be a better fit. We want to use RDS for better logging and auditing to improve security and accountability, while DynamoDB will handle personal watchlists for fast lookups. This balances performance with the need for structured access tracking. (updated web app database schema)
During last week’s status report, we identified the need for a circuit to support the dash cam because the car’s power supply shuts off immediately when the engine is turned off, while our RPi5 requires additional time to properly shut down to prevent data corruption or potential damage. After designing a preliminary solution, we determined that incorporating a supercapacitor would be effective, as the shutdown process takes approximately five seconds. While researching, we also came across a pre-made module called the UPS HAT for the RPi, which addresses a similar issue. However, we would like to discuss in next week’s meeting whether our custom-designed circuit or the UPS HAT would be the better fit for our overall design. (UPS hat)
