R.F.N.T.

(Radio Frequency Navigational Tracker)

Josh BingamanRyan HitchlerJohn Maitin

Fabien NervaisMatt Sharp

Capstone Fall 2004

Main Objectives

Create a vehicle that will remotely track a high frequency RF transmitter, which may or may not be stationary.

Detect the signal strength of the target in order to determine which direction to go.

The practical application is a golf caddy that will follow a golfer when requested.

Possible Project Extensions

Add proximity sensors in order to circumnavigate obstacles.

Cell phone used to control vehicle. GPS navigation. Signal Acquisition Improvement Additional RF controlled functions.

Basic Layout

Base of vehicle

Antenna Unit

Processor (Inside Base)

Processor/ Main Board

RSSI

Motor

DigitalCompass

Motor (Left)

Motor (Right)

Digital Compass

MotorControl GPIO?

GPIO

RS/232

RS/232

Base of Vehicle

Antenna Unit

Hardware Block Diagram

Software Implementation

One basic algorithm, two variations Initial design

Antenna stops spinningUnit stops to turn

Desired designAntenna continuously spinsUnit turns dynamically

Algorithm For Operation (Initial)

Algorithm For Operation (Desired)

Mechanical & Control Systems

Potential Concerns / Unknowns

Rotating Antenna & Motor Mount

Antenna Construction & Actuator Torque

Ground Wheel Control Sensor Resolution Terrain Tower Height Control

Addressing Anticipated Difficulties

Rotating Antenna & Mounting Motor Wheel vs. chain How to attach, depends on dimensions

Antenna Weight / Shape & Actuator Torque dependant upon antenna implementation wind resistance, etc…

Ground Wheel Control motor specs unknown, researching new motors possible substitutes – how to mount??

Difficulties Part Deux

Sensor Resolution Compass

magnetic distortion maybe present hard-iron calibration should be performed

Data acquisition issues Frames of reference

Terrain too rough considering additional functionality, safe mode / shutdown vehicle durability

Tower Height Control motor specs unknown, may not be necessary Automate signal query

Power Specifications

12V car Battery, AA/AAA Battery, Dry Cell

Two 12V wheel motors

One 5V antenna motor

Base and antenna Circuitry

Low-powered transmitter

Transmitter

Low power transmitter ideally a remote (key-fob)

Overview of Power Concerns

Power transformation on navigational unit

Power noise due to rotation

Power cable routing to rotating mount

Power Concerns Addressed

Power transformation on navigational unit Voltage regulators

Noise due to antenna rotation Decoupling caps

Power cable routing to rotating mount Rotating contact plates

Rotating Mount

• Transmitters

• Grooved Plates

• Software

Antenna

Rotating Mount Shielded

Unidirectional Antenna Digital Compass

mounted with Antenna Synchronization of

Compass and Antenna

Transmitter/Receiver

•916 MHz RF•16 Bits Transferable•RSSI (Relative Signal Strength Indicator)

Schedule

Thank You

Questions

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