BLAKE DIDIER LESSAGE GABRIEL G.U.N.D.A.M.

What is it? A robot whose primary function is solving mazes of varying types while transmitting the layout of the maze back to a computer/laptop to display said maze to the user Maze will be custom built with a layout capable of being changed to any type depending on the user’s specifications

Motivation

Features Wall Detection Wireless Communication Maze Solving Discover entire maze layout Accept path inputs from user Forward and backward movement Isolated rotation

Parts Being Used Two IR Sensors for the sides Two ultrasonic sensors for the front and back RFM12B-S2 Wireless Transceiver Robot Chassis Java GUI Interface

Wireless Subsystem -ROBOT MODULE -COMPUTER MODULE

Robot Module PCB layout  MSP430 Microcontroller  Interface with Main µC through SPI or I 2 C  RFM12B RF Transceiver  Interface with MSP430 through SPI Schematic

Computer Module PCB layout  MSP430 Microcontroller  RF µController  RFM12B RF Transceiver  Interface RF µC through SPI  CP2101 UART to USB  Interface RF µC through UART to PC USB Schematic

Wireless Protocol TX node (Robot Module)  Initially Transmitting to Establish Connection RX node (Computer Module)  Initially Listening to Establish Connection Collision Avoidance Algorithm  Avoid TX or RX at the same time

Wireless Protocol Employ AES-128 on both the Robot and Computer module  Data encryption of TX packets on each node  Data decryption of RX packets on each node

RF Microcontroller (MSP430) Encrypt data in AES-128 algorithm Read data from RF Module for RX Send data to RF Module for TX Specifications:  SPI, I 2 C, and UART interface  16-bit Architecture

RF Transceiver (RFM12B) Low power: V High data rate: up to 115.2kbps Programmable TX and RX bandwidth Automatic Frequency control SPI interface 16 bit RX FIFO Two 8 bit TX data registers

RF Transceiver (RFM12B) FSK Modulation Scheme RSSI Strength indicator Operating Temp ˚C At 433MHz bandwidth  Max TX/RX current 24mA/13mA  Range > 200m

UART to USB Bridge (CP2101) USB Bus powered powered: V Baud rate up to 921.6kbps On chip voltage regulator Virtual COM port for GUI

Range Finder Subsystem -INFRARED SENSORS -ULTRASONIC SENSORS

Infrared Range Finder (GP2D120) Operating Voltage 4.5V to 5.5V Operating Current 33 to 50mA Measures 4cm to 30cm Analog output

IR Range Finder Function

Output Voltage (V) vs. Reflected distance (cm)

Ultrasonic Range Finder Measures 15cm to 510cm Operating Voltage 8-12V Current consumption 14mA Ultrasonic Frequency 40kHz SPI/I 2 C interface Onboard ATtiny26 µController

Physical Maze Plastic, Wood, Metal, Rubber, and Paper reflect ultrasonic waves. Things to consider:  Cost : Metal > Plastic > Wood  Easy of Manufacturing: Metal > Plastic > Wood Lap Joints

Lap Joint

Maze Layout

Nodes Nodes will be “placed” at intersections and turns. These nodes will be stored in a list on the computer side. The node will have information on their location, the amount of neighbors they have if discovered, and the distance between the neighbors. Information on how far the robot has traveled before reaching an intersection or turn will be stored and sent to the computer to allow for accurate representation of the maze and its dimensions

Walls Using the information given to it by the robot itself, the location and length of the walls will be able to be determined as well as any turns and openings along these walls. This information is then used to draw out the actual maze.

GUI Maze will be presented in its own frame along with options for the user to request either a maze be solved (if not already), the maze be explored, or a particular path be traversed or destination reached.

Maze Solving (Path Finding) Algorithms Wall Follower  Simple maze solving solution that involves following the left side of the maze, including any turns that may follow. Will be the default maze solving method  This solution is only valuable in certain maze situations. If the entrance of the maze happens to lie in the center and not on the outside edge, or if a wall happens to lie on its own with no connections, it will fail

Maze Solving (Path Finding) Algorithm Tremaux  This algorithm assigns values to paths according to how many times it has been traversed. At a fork in the road, if there is a path valued at 0, it will take it. If not, and the current path is a 1, it will backtrack and take the next smallest path value. If the current path is a 2, the smallest valued fork will be taken. This method will be used if it is determined that the maze cannot be solved with the wall following method

Entrances and Exits There will be a single entrance and exit for the maze A check will be done to determine if the maze type can be discovered simply through the entrance’s characteristics. If surrounded by walls, it is safe to determine that the robot is inside of the maze rather than outside of it. This is a signal to use Tremaux, as emphasized previously. Exits can be within or outside of the maze. A check will be done to determine the distances on all sides. If these sides exceed the pre-determined dimensions of maze, we have found our exit.

Format of Information Upon reaching an intersection, along with placing a node, the robot will write to the port how far it has estimated its travel, the number of turns open to it (left, right, straight ahead) The program will read this information and use it to construct the next set of walls. Each path drawn out will simply be two lines of a pre-determined width between them

Classes Nodes  Neighbors  Location  Dead ends  Part of path  Heuristic  detDistDest()  getLocation()  getHeuristic()  getDistCurr()

Classes Path  Nodes  Distance  Final (bool)  getNextNode()  removeNode()  isDest()  isSource()

Classes Walls  Location1  Location2  Length  Width  Stand Alone (Bool)  getLoc1()  getLoc2()  getLength()  getWidth()

Classes Robot  Location  State  Solving  Exploring  UserPath  getState()  getLoc()

Explore Maze The robot will explore and discover any and all paths within the maze using a hacked version of the Tremaux algorithm. Instead of having the sole purpose of discovering an exit, a list of all nodes and paths along with their number of times visited will be stored. The robot will then work through this list and make its way to each node using a combination of Tremaux and A star.

User Input Path The user will be able to input a path for the robot to take inside of the maze. The user can either input an exact path for the robot to take or…. …the user can simply select a destination and the robot will use A* path finding to find the shortest path to the destination.

A* Once a destination node is chosen, the algorithm takes into account only the destination and any neighboring nodes to the current position of the robot. Cost (distance) of moving a node is calculated for each neighboring node not blocked off by a wall Estimated cost of reaching destination is then calculated The smallest calculated distance and the node that has achieved said distance is then chosen as the next node to travel to in the pre-path. Once a path has been chosen, the robot then traverses the maze using the path

A* If user selects a location that is not a node, a new node will be placed at the user’s desired location This is necessary to enable to algorithm to actually find a path to the destination

Specified Path User can also highlight a path of nodes to traverse for robot User will select nodes it wishes to be incorporated within the path itself or simply draw out a general line to follow If general line made, the program will determine any and all nodes that are sufficiently close to path to incorporate within the list of nodes needed to traverse it

Path Completion Once the path is completed, program will store the path (simply a list of nodes and the order they should be traversed) The program will then write to a serial port to be read by the robot itself Upon reaching a node specified by the program, the robot will request the next instruction on whether to turn or continue straight on its path. This check also involves determining if the node it is currently at is the destination

Progress

Budget PartModelPrice

BlakeDidierGabriel

QUESTIONS?