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?
Unfortunately, our size requirements are most threatened by the battery size, because everything else can be quite small. Unfortunately, small and powerful batteries are presumably not on the market for proprietary reasons, so we can only have big bulky batteries. The battery we currently have will last for about 8 hours, which is the max time that one of our surveyed users wanted it to last for. Unfortunately, that means it must be bulky, either in the width or height direction. We are debating how necessary it is to cater to the person with the max time requirements, or whether we should focus on the lower time that the majority of the respondents stated, which is up to 4 hours straight. This would allow us to use lighter and smaller batteries, which would be more comfortable for the user. Thus, we will be asking our target demographic about these tradeoff decisions and what they would most prefer when we meet them on Monday.
As another option, we were also considering whether users could be able to swap out the size of the battery being used to fit their use requirements. Unfortunately that would add more designing of the battery pouch to make it fit both options (otherwise a smaller battery in a large bag wouldn’t save any space), and we’re not sure if this is something that’s really crucial.
Were any changes made to the existing design of the system (requirements, block diagram, system spec, etc)? Why was this change necessary, what costs does the change incur, and how will these costs be mitigated going forward?
The width requirement was returned in response to feedback in the design review Q&A, and modified to 70 mm to match the estimated width of the current design of our bracelet. This does not incur any specific cost at the moment; however, it might make the bracelet less comfortable for users. This potential cost will be identified if it exists through the planned integration test, and will be mitigated by rearranging the parts to create a bracelet with a width smaller than 70 mm.
Right now, the design only has one battery (because calculations showed that the bracelet might be able to meet the battery life specifications with only one battery) and two microphones (because there are only two Arduino digital input pins on the Beetle). A possible cost of using only one battery is that, if the components pull more current than expected, the battery life will not meet requirements. In that case, we would consult with staff to choose an alternate battery configuration that meets our requirements. A possible cost of using only two microphones is that there are fewer chances to correct errors; if one microphone’s input is incorrect, it has a greater effect on the overall calculation. We can mitigate this by processing microphone input in the code that converts microphone inputs to dB values.
Provide an updated schedule if changes have occurred.
The Gantt chart was updated; the most significant change is deleting a double-count of Bluetooth setup in both the hardware and software sections. We have extended some end dates for tasks, but the final parts of the project (integration and testing) have the same start/end dates, so the project remains on schedule overall.