Robotic Sensor Network: Wireless Sensor Platform for Autonomous Topology Formation Project: Sponsored By: Advisor: Dr. S. Jay Yang, CEManager: Steven Boughton, ME Brian Teaney, CERyan Johnson, EE Jack Tsai, EEMatt Hrivnak, IE Gregory Rosenblatt, MEShannon Buckland, ME

Presentation Overview Project Overview Problem Statement, Design Process, Project Constraints Prototype Design Design Overview, Testing and Problems Encountered Final Design Mechanical and Electrical Redesign, Software Development, Final Testing Future Plans Questions

Problem Statement To develop a group of sensor platforms that can communicate with one another wirelessly and move from original deployment locations to form a desired network topology that offers full, energy efficient, and robust coverage. The platforms will be relatively small and lightweight. They must be able to work as a group to maximize the sensor networks life span. The end result of this project is to have a functioning group of no less then three sensor platforms that can be used as a test platform for future research and expandability.

Design Process (Phase I – Winter 2003) 123 Locomotion Shannon Greg Sensing Jack Matt Communications Brian Ryan Project Manager / Project Advisor Locomotion Shannon Greg Sensing Jack Matt Communications Brian Ryan 4 Initial Concepts Final Recommendations Hardware Shannon Jack Matt Software Brian Ryan Greg Objectives and Specifications Hardware Shannon Jack Matt Software Brian Ryan Greg Mechanical Electrical Movement Sensing Communications 5 Topology Final Prototype Design Needs Assessment Concept Development Feasibility Assessment Objectives and Specifications 4 5 Analysis and Design Phase II Spring 2004

Design Process (Phase II – Spring 2004) 68 Electrical Ryan Jack Mechanical Shannon 9 Final Design Initial Testing Problem Assessment Redesign Final Testing 9 Electronics Ryan Jack Movement Brian Shannon Greg PIC Brian Problems 7 Electronics Ryan Jack Movement Brian Shannon Greg PIC Brian Recommendations Hardware Shannon Jack Matt Software Brian Ryan Greg Mechanical Electrical Movement Sensing Communications Topology Formation Phase III Fall 2004

Project Constraints Budget –Original funding fell through –Final budget not approved until March 19 Timeline –Accelerated design time: steep learning curve –2 phases: Prototype and Final Design Limited Lab Equipment and Software –Limited shop time –PIC programmer –Design Software

Prototype Design Overview 3 Tier Layout –Weight distribution –Location advantages –Ease of assembly –Ease of redesign Locomotion Tier A –Motors, tires, power Sensor Tier B –IR sensors Communications Tier C –Prototype board A B C

Prototype Design Specifications MICA2DOT –Run on an Atmel ATmega128L running at 4MHz, w/ 128k of program memory. –Handles the communications and network topology. Sharp GP2Y0A02YK IR Sensor –Less influence on the color of reflected objects, reflectivity –Current required: 33mA –Analog voltage corresponding to distance PIC18F458 model –Up to 40MHz clock. 8k of program memory. –Will monitor the infrared sensors and control the locomotion of the robot. Motors –Bipolar Stepper Motor –12 A

Prototype Testing and Problems Encountered Turning Capability –Units could not execute turns –Solved by widening the base to 5” by 9” Programming the PIC –Initial PIC selection did not match programmer compatibility –Solved by selecting different PIC micro controller (PIC18F458) Motor Control / Power –Supply currents insufficient to drive original motors –Selection of new motors and addition of higher rated regulators –Bipolar Stepper Motor (1.8 o step, 650 g-cm) Overheating –Units were prone to overheating in a matter of seconds –Solved by adding heat dissipation elements to final design

Final Design Redesign Mechanical Redesign –Aspect Ratio (2:1) –Tire Coupling –Sensor Mounts (4 vs. 8) –Material Electrical Redesign –Board Size –Voltage Regulation –Heat Sink –Battery

Final Design Software Development The final software development issue involved integration of the three main components that had been programmed separately. Motors/Sensors Communications Topology Formation Algorithm

Final Design Software Integration Topology algorithm interfaces with other components Integration with Motors/Sensors –Topology interface calls directly-related functions Integration with Communications –Intermediate code created to link the Topology interface with proper calls to send and received messages PIC Programming Issues…

Final Testing Hardware Testing –Movement –Errors in Turning Software Testing –Communications Verification PIC Testing –Unsolved Problems

Future Work Reliable, user friendly, and upgradeable sensor platform –Programmable via wireless communication –Easy to maintain and upgrade Scalable and robust topology formation –Distributed control leads to fast convergence –Adaptive to sensor failure or energy exhaustion Application driven topology adaptation –Mission critical sensor network –Formation adapts to application needs