What are the most significant risks that could jeopardize the success of the project? How are these risks being managed? What contingency plans are ready?
The main risk we have right now is our control loop for the pump to stop working. We have been running into a hardware bug that we haven’t been able to figure out where after a certain amount of time of testing the pump, it no longer receives any signals or voltage from its power supply. We imagine this should not be an issue during the final demo due to it only happening after 5+ hours of testing. Unfortunately, we do not have a contingency plan as swapping out a pump is not as simple as it sounds thus we will make sure not to stress it too much before demo day. In the event of total pump failure, we are still able to demonstrate pour patters as well as the entire webapp, we just will not be able to brew coffee.
List all unit tests and overall system test carried out for experimentation of the system. List any findings and design changes made from your analysis of test results and other data obtained from the experimentation.
Flow rate test – Through this we learned that there was a minimum and maximum current that we could send the pump before it didn’t spin at all, thus we had to add a physical flower restrictor to change its flowrate as well
Water heater test – Through this we learned that our initial PID implementation had a small overshoot in terms of the temperature it would achieve. We repeated this test until we were able to refine our PID values to get a temperature +/- 5 degrees of the desired temperature
UI/UX stress test – Through collecting data for UX of our webapp we learned of some pain points for user unfamiliar with pour over coffee. We have since implemented features to help alleviate these, such as active step highlighting, profile sorting, and a friendly little coffee bean guy!