Blog 5 Capstone Project Update

We are back for more! 

After blasting off into the summer and forgetting all about our project, we have made a safe landing into our new and last semester of fall 2024.  

Some of us will be graduating, while others may continue with higher education. But one thing is for sure: our Capstone project will come to an end this December. 

But never mind that! Join us for an exciting update on what we have completed so far. 

Our most proud accomplishment task for the period of Aug 19th - Sep. 6th is meeting up with our machinist, Jamar Murray. Not only is he fun to talk to, but he's extremely experienced in what he does and provides insightful feedback on our design updates.  The design has been evolving every time we meet up with Jamar and our NASA mentor, Thomas Cognata. New measurements and additional parts have been added to accommodate the benchtop testing area. This includes a honeycomb pattern on top of the encasing for better airflow and mounting L-shaped brackets to secure the enclosure. On the electrical part of the project, new equipment has been acquired to power the heating pad. Two metal enclosures to separate high and low voltage sections of PWM-driven current and wire a diagram schematic for future documentation. 

The main task still in progress is machining the enclosure and the heat-dissipating device. It is a challenge to bring together without the full CAD drawing and the exact measurements. Even then, we still have to put it together and make sure everything fits according to our specifications. It is crucial that we take our time in the design to avoid future modifications that can delay our execution.

From September 7 to September 20, we plan to finalize any minor design changes needed to accommodate the constraint of the machinist at UH's machining capabilities, clearing them with our sponsor. Additionally, we will finalize additional design changes per our sponsor's new additional constraints. No major design changes are happening, but our team learned the thermal interface where we will be testing our device will be vertical, so our plan to use gravity to hold our enclosure over the test bed will not work, and as such additional geometry for fasteners must be added to our design.

The first iteration of the Arduino code will be completed, as presently it's approximately ¾ of the way complete, incorporating the behind-the-scenes analysis necessary to display the heat rejection rates, surface temperature, and simulated actuation angle on our device. Additionally, all components required for the device to work will be in our possession. The major milestone being completed from September 7 to September 20 in reference to our Gantt chart is the Assembly and Initial Testing milestone.

The team anticipates two potential obstacles over the next two weeks: an unforeseen delay or problem with fabrication, and an issue with validating the fan speed. At the time of writing this blog, the team is making last-minute design changes based on requests from the machinist and our sponsor at NASA. This is the final step before the fabrication of our components begins, which is expected sometime next week. If a component is fabricated incorrectly, the materials will need to be reordered and refabricated, consuming valuable time from the validation and testing phase. This is a critical time for the team, which is why we have maintained close communication with all involved parties to minimize mistakes. The next challenge is developing a validation plan for the fan speed. The team has not yet decided on a solution for measuring the fan speed. While the fan has a built-in tachometer, we are not satisfied with relying on a single measurement method, as we are unsure of its accuracy. The team is working hard to find a solution to this issue.

Figure 1: Visual representation of the heat dissipating device demonstrating the location of the components and the acquired aluminum plates. 

Figure 2: Redesigned Version 1 of top plate of the “sandwich” design with side fixtures to secure the encapsule, openings on the plate to secure it with M5 screws, and screws fixed to the plate to secure the heat sink and fan.

Figure 3: Redesigned Version 2 of top plate of the “sandwich” design with side fixtures to secure the encapsule, openings on the plate to secure it with M5 screws, and openings on the plate to secure the heat sink with M3 screws. back for more!