Administrative Introduction Our goals for this project are for the three robots to work together intelligently to complete a maze faster than an individual robot would be able to. Not only did we want a cost effective robot we wanted to make the whole process of an autonomous robot solving a maze more efficient and faster.

Project Goals To build 3 robots that work together to navigate a maze The robots must communicate wirelessly and analyze information intelligently The robots must use each other’s information to gain information on how to solve the maze The robots should be able to figure out where and how far the walls are from them and record which routes have been taken to learn the maze We want it to seem as if each robot can see through the other two robots eyes and as if they were working with one mind

Specifications and Requirements 3 robots that communicate through a wireless connection The base of the vehicle should be able to rotate 360° The code should execute immediately and the robots should not pause longer than 10s Robots should be able to measure their distance from the wall to a degree of error not greater than 4 cm Robots should be able to store maze information and send it The robot should be able to identify dead ends in no more than 5s Each robot should cost less than $150 to construct

System Design Diagram

Microcontroller Choices

Microcontroller – Arduino Duemilnaove ATMEGA328 USB Interface Cross-platform Open source 32 KB Flash Memory Well documented

Printed Circuit Board PCB123 software $100 student credit from sunstone Prototyped on the Arduino board 2 layer design Using through hole and surface mount techniques

Batteries

Power Needs Voltsmilliamps Ultrasonic Rangefinder DC Motors Bluetooth Module 3.330

Voltage Regulation All parts can run off of 5 volts DC Stepping Down 7.4 volt battery LM317 regulator- adjustable output with two external resistors

H-Bridge The SN Quad Half H-Bridge Capable of driving high voltage motors using TTL 5V logic levels Can drive 4.5V up to 36V at 1A continuous output current

Texas Instruments Voltage Regulator Advantages 3 Terminal Regulator High Power Dissipation Capability Output Current up to 1.5 Amps Internal Short Circuit Current Limiting Input Voltages up to 40 V

Testing DC Motor/H-Bridge wheels test Chassis/Locomotion test with wheels turning on axis Rangefinder test Bluetooth test

Base Vehicle In deciding the body of the autonomous robot a number of concerns came into play. The robot needs to be sturdy yet lightweight in order to mount all the additional parts The robot must be able to turn on a dime and navigate corners in order to travel the maze effectively The platform of the robot should be a disc like shape

Base Vehicle Frame of vehicle Motor Navigational system

Frame of Vehicle The considered materials for this robot was polycarbonate plastic and aluminum The final choice was the plastic light weight Easy to use Cost effective

Servos DC Motors RC Motors Stepper Motors For our robot a dc motor was chosen

Navigational system The navigational system we look at was Two wheel Three wheel Four wheel

Four Wheel System Pros: Better stability because its center of gravity is in a rectangular form The four wheel provides extra balance Its turning ability is just like a car Cons: Its much harder to build and much more costly

Three Wheel System Pros: Greater accuracy when fast turns are required Cons: Center of gravity is in a triangular shape which makes it very easy to fall Does not perform well on any form of rough terrain Not as efficient or cost effective

Two Wheel system The two wheel system is what was chosen for our design in the autonomous robot mainly: It meet our desire specification Its will be light weight Able to turn on a dim More effective in maneuvering the maze Cost effective

Labyrinth

Simply Connected Maze

Disjoint Maze

Tremaux's Algorithm If you encounter a new junction: Pick a direction at random If you are traversing a new path and you encounter an old junction: Turn back If you are traversing an old path and you encounter a old junction: Take a new path if available, otherwise take an old path If you encounter a dead end: Turn back

Graphs

Mazes as Graphs

Graph Traversal Search (Vertex startV) List vertices = empty List Set visited = empty Set Add startV to vertices while (vertices is not empty) { Vertex V = remove element from vertices if (visited does not contain V) { // Handle V here // (e.g. check if destination Vertex) Add V to visited for every Vertex X connected to V if (visited does not contain X) Add X to vertices }

Constructing the Maze

Bluetooth Successes and Difficulties Successes – Maximum distance is up to 100m – Has an indicator LED – Supports Windows Bluetooth stack – Windows automatically links with Bluetooth Difficulties – None to date

SeedStudio Ultrasonic Range Finder Successes Successes – Breadboard friendly – Arduino library ready – The size is light weight – Wide range from 3 cm – 400 cm

SeedStudio Ultrasonic Range Finder Difficulties Difficulties – Efficient communication between the micro-controller – Best if used in a 30° Practical test of performance, Best in 30 degree angle

Project Budget and Financing The Budget to Date Part NameVendorQuantityPrice SeeedStudio Ultrasonic Range Finder Robotshop2$38.25 Bluetooth USB Module Mini Sparkfun2$33.58 Base Vehicle Robotshop2$60.00 Micro- controller Amazon2$30.00 Total161.83

Project Budget and Financing The Budget to the End of the Project Part NameVendorQuantityPrice SeeedStudio Ultrasonic Range Finder Robotshop3$53.25 Bluetooth USB Module Mini Sparkfun3$44.58 Base Vehicle Robotshop3$80.00 Micro- controller Amazon3$50.00 Total$227.83

Current Progress Research – 100% done Design – 95% of the design is done Parts Acquisition – 80% complete Prototyping – 20% complete Testing – 10% complete Overall – 25% complete

Questions?