NEDMO

Our NEDMO is comprised of NAVCON for controlling the navigation and actions of the 0TILUS, and FUELCON for controlling the pairing and refueling. NAVCON and FUELCON are connected by a wire tether for signals, and there is a fishing line in the wire bundles to take the tensile stress away from the wires. All NEDMO devices are designed to be handheld to allow for mobility, as we expect the operator would need to constantly relocate during a game play.

NAVCON

The NAVCON is tasked with receiving control inputs from the human operator and transmitting them to the PIC located within the FUELCON. Modeled after a traditional game controller for ergonomic efficiency, the NAVCON features two joysticks and three buttons for intuitive operation and ease of use.

The extra holes on the NAVCON were initially designed to accommodate additional buttons, as the mechanical design was completed before the finalization of the communication protocol. However, the finalized communication protocol restricted the number of buttons to three, leaving the additional planned buttons unimplemented..

The NAVCON is about 165 mm wide, 110 mm long and 70 mm thick

FUELCON

The Lasso

One of the requirements for the fueling motion is that it should look as silly as possible, it shouldn't be as simple as holding a button. So we came up with the idea of making swinging a lasso the refueling motion. We wanted to design the sensing such that there's no way to trick the sensor by making it think the lasso swinging is being performed instead of actually performing it, so we thought having an accelerometer at the end of the lasso would solve this problem. When the accelerometer detects constant acceleration beyond certain threshold, it counts it as refueling, and it's near impossible to produce a constant acceleration past the threshold we set (3g) without swinging the lasso. However, this sensing method comes with several challenges. First, most of the accelerometers we could find use I2C for communication, and it takes quite a bit of effort get I2C working on the PIC32. Similar analog accelerometers cost quite a bit. Plus having the signal wire connected to the accelerometers constantly going around in circles could tangle the wire, put extra stress on the wire, rapidly fatigue the wire, making the reliability of it very uncertain. With these considerations, we decided to use a rotary encoder as means of sensing instead, with the thought that if we set the rotation speed threshold for the lasso pretty high, it's also pretty hard to cheat the sensors.

Section view of the lasso handle

The lasso handle holds all of the sensing hardware. At the top, there is a arm attached to the rotating shaft, and the lasso (a weight) is attached to the hole in the arm. By swinging the lasso, the arm along with the rotating shaft is turned, and the encoder disc at the end of the rotating shaft sends out pulses, registering the turns. The shaft rides on bearings at both ends for smooth rotation.

The Main Unit

The main unit houses most of the electronic components for the NEDMO. For the user interface, it also features a slider potentiometer, a push button for pairing functions, and an analog dial driven by a servo to indicate the fuel levels.

Keeping consistent with the classical theme, the dial design is inspired by Breguet, which is an icon in clock making.

FUELCON main unit is designed to be held by one hand

Page updated

Report abuse