On this page, we will provide a detailed mechanical outline of the NEDMO design. NEDMO was designed in two separate parts: NAVCON and FUELCON. In the sections below, we will discuss the specific specifications of these designs.
The 3D model of our NAVCON is a simple Duron box with mounting holes for the linear potentiometers and joystick. These dimensions were derived from data sheets, calipers, and estimation. The front and back, right and left, and top and bottom sides each have identical dimensions. On the right wall, there is a small hole, roughly half an inch in diameter, for the tethers to exit (not visible from this angle). The top surface was customized to accommodate the dimensions of the linear potentiometer and joystick. The physical dimensions of the box are 5 inches by 4 inches by 1.5 inches.
The physical NAVCON, slightly wet after our demonstration day, shows the joystick in the center, protruding from the inside of the box and easily accessible for the user. On the bottom, you can see the handle for the linear potentiometer, as well as the hardware used to mount everything.
One interesting issue we encountered with the linear potentiometers was that the screws used to mount them were slightly too long and interfered with the internal structure of the potentiometer. This contact caused the potentiometer to short. We tested the potentiometers to ensure they were operating properly, and they were, until we mounted them into the Duron box. Initially, we thought the potentiometers were faulty until we realized that the screws were causing the short and preventing us from obtaining variable resistance.
The 3D model of the FUELCON. As you can see, it is a fairly simple Duron box again. The top and bottom, left and right, and front and back panels all have identical dimensions. The top panel is customized to allow for the necessary user interaction features.
Along the top, we made two custom cupholders sized to hold roughly half of a red Solo cup, with a custom mounting point for limit switches at the bottom. These cupholders were 3D-printed and epoxied into position on the Duron box. The top panel also has a hole for the potentiometer, a mounting point for the 9g servo to display the fuel, and a spot for the arcade button. All dimensions were taken from their data sheets.
The physical dimensions of the box are 8 inches by 6 inches by 3 inches.
The physical model of the FUELCON closely resembles our CAD model, with a few customizations for practical use. The potentiometer has numbers indicating which direction corresponds to each boat. On the top surface of the potentiometer, you can see an arrow used to show its orientation. In the center, we have the servo, which is oriented opposite to the CAD model, showing an open hole below it because the panel was never updated after we planned to use an eight-segment display to represent the team number, but we found it difficult to implement and decided it would be easier to put the numbers around the potentiometer. The tether is visible coming out of the left side of the box, with the hole drilled once we determined which side we wanted the fuel to be on.