‘Iole o Mãnoa Mouse of Mãnoa

Team Members Jeff Fines Designer, Fabricator, Programmer & Thomas Matsushima Designer, Fabricator, Programmer

Overview We will be designing and fabricating small robotic mouse. The mouse will be programmed to find the center of a 16 x 16 maze.

Initial Goals We will design and fabricate a micromouse that can consistently and quickly navigate to the center of a maze.

Chassis Final Status We have: Shaped a base with enough area to hold the mouse components and the ability to easily traverse diagonally through the maze. Ordered necessary parts. Decided to use bipolar motor steppers. Cut metal attachments which will be used to screw down the stepper motors and sensors. Decided on placement of sensors

Design Structure Flying Rabbit Soldered circuit to PCB board. Four eyes in front, with a round end for easy turns. Two stepper motors which control wheels that spin like crazy.

Solving Algorithm We have decided to implement the “Flood- Fill” method for navigating through the maze. Where the center cells are is Cell 0, the four cells around that are initially Cell 1, and so on for a total of thirteen layers of cells. From Cell 13 the mouse will move by choosing the cell closer to the center, i.e. moving from Cell 13 to Cell 12.

Mouse Modules Mouse Brain Module –Microcontroller –Programming Solving Algorithms Tracking Algorithm Sensor Module –Physical Sensors –Analog to Digital Converter Motor Module –Motor Circuit –Motor Logic Controller Power Module –Power Supply –Power Converter Chassis Module –Motor Mounts –Sensor Mounts –Base

Motor Module Using Bipolar motors, H-Bridges, inverters, and Mosfets. We will be able to produce a micro-stepping mouse. Rather than rotating in a full step, the mouse will adjust its microstepping accordingly in order to center itself in the maze creating proper sensor readings.

Motor Circuit Schematic

H-Bridges are necessary to control the Bipolar motor because we have to reverse voltage through the coil to properly control the motor.

Logic Circuit Schematic

The Inverter will allow us to control the mouse to control each motor using only two inputs and to micro-step using only four. Mosfets are used to remove power to H- Bridges to allow micro-stepping.

Tasks Accomplished Assembled and Tested the Circuit for proper mouse behavior. Transfer the circuit from a proto-board to a soldered circuit on a PCB. The Flood-fill algorithm. Locate the center. Teamwork.

Problems Encountered Sensor Issues –Mistaken Identity: sensors had to be removed from chassis several times, and were mixed up, so when the code asked for a reading from Sensor 0, it may have been reading another sensor, causing an incorrect reading for the mouse. –Drilling holes to screw the sensors to the chassis, we were not precise so we had to make the sensors fit. –Soldering iron would not get hot! Programming Issues –Understanding the algorithm. In flood-fill we must use arrays and understand how each cell represents a cell in the array, but not as simple as it sounds. –When flooding the mouse would kick out of the code. –When transferring the circuit from the bread board to the PCB the circuit reacted differently, and concluded that the toroids were the cause. –Our stepping was off during the competition, it used to be able to turn 90 degrees, but ended up making 45 degree turns. Time –Sleep deprivation.

Future Improvements Our code could use some optimizing. Wires could be held together in its respective group to make it look less messy. Solder could definitely be done better. Add the UH Mãnoa logo.

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