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Sea Vessel Project
This project required a team of three people to design, code, and build a boat out of vex components and/or store bought products under $10. The boat must have an on and off switch, throttle, and a turning mechanism, with everything controlled by a remote.
When starting the project, I wanted to create either a propeller system or a paddle system. By using a decision matrix, our team was able to confidently say that the propeller system would be the best way to maneuver the boat. A 3 wire motor would be connected to a sprocket in a speed gear ratio in order to both keep the motor high above the water as well as outputting the best combination of speed and torque for the given weight and size of the model. A three wire servo motor would be connected to the base of the boat with bevel gears to turn the rudder. Pool noodles would be secured to the sides of the front as well as the rear of the boat in order to maximize stability. A flashlight would be connected to the front with a light sensor to detect a threshold value of low ambient light. A sonar sensor would also be added to the base, held up by standoffs. When the boat model senses an object within eight inches of the sensor, the boat would reduce its speed to half for a half of a second, then quickly shut off. A compact remote controlled would be made, having access to all buttons at the same time.
There were many early successes to the project, but there were also many challenges that we faced throughout the project. First, we needed to decide on the best model possible, so we overcame that challenge by creating a decision matrix to evaluate our designs in an objective way. Next, making a turning mechanism required bevel gears, which were hard to mesh at the right angle. Therefore, I needed to provide directional reinforcement structures in order to hold the two perpendicular axles in place. Securing each axle from both the motor end and the open end would ensure maximum stability. When initially testing the boat in water, the rotor was in the back of the boat, so it would tip. I needed to flip the direction of the rotor so that it would be located in the middle, maintaining an adequate centroid. I noticed that when turning on the propellers, the boat would try to rotate backwards due to the opposite forces of thrust. I decided to fix this issue by adding a stabilizer, consisting of a pool noodle connected to a panel and a clamp. This method proved effective in balancing out these thrust forces. As far as software, being able to compile the on and kill switch, the thrust mechanism, and he turning mechanism was a challenge. By adding 2 layers of “while(true)” statements, we were able to create closed loops in which the components would continue to function in an orderly manner. After finalizing the code, there would be parts which would glitch out due to unknown reasons. It would work only after power cycling the cortex, while it worked every time before. Overall, the rest of the project was pretty smooth other than these aspects.
Inch Cubed Project
For the inch cubed intro project, we needed to design any object with a total model material of less than one inch cubed. We were given total freedom to push our imagination to the limit in order to push the 3D printer to its limits. The overall parts had to be less than 6 inches long and 4 inches tall. Other than those, there were very few restrictions and limitations.
Going into the project, I knew that I wanted to make a very complex part or assembly of parts off the bat. I love biking so I decided to model my bike after much thought. I would end up designing a frame, wheels, pedals, pedal bars, handlebars, shocks, a seat stand, and a seat. I would end up using the thinnest paper clip. I wanted to maximize the size of the object for the overall volume, so I created a hollow bike frame. I decided not to create axles because they would be way too brittle. The wheels were relatively thin as they were the source of the most volume. All of the parts were extremely intricate and detailed for the scale of the part. The parts would be generated upwards in order to make robust parts. After printing, I decided to place a majority of them into the bleach bath in order to dissolve the acidic support material. I finally assembled all of the parts together to create the bike using ABS solvent.
There were many challenges when creating this bike assembly. First off, the diameters of the holes of the frame and the pipes rounded to the nearest 0.01 inch, thus making all of the measurements off. I had to whittle down the front pipe in order for it to fit correctly into the bike frame. The seat pipe needed to be narrowed down as well. I used a drill bit to create a tiny hole in the pedals so that they would eventually be able to fit in with the pedal bars that I had created. The ABS solvent was really tricky to use. I put on the pedals as one of the first steps, which was a mistake in hindsight. They were extremely flimsy and it resulted in me needing to get another pair of hands to hold the frame as I made all of the necessary welds to the bike. The pieces kept falling off due to the scale. Once I finished the bike and let it dry overnight, everything ended up coming out just fine! I am extremely proud of the project as many many hours went into designing and editing each part on the bike was excited that everything fit together in the end.
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