Easy on the Tini

Bill Barker

Carey Davis

Ben Irwin

Travis Majors

Cell phone detector

Description and Goals

To create a robot that detects RF signals (cell phone signals) then moves toward the strongest signal.

Notifies cell phone user about use in that area.

Outline of Approach

Create a robot with two servo motors

Fashion RF detecting antenna(s) on the robot chassis

Mount IR sensors to aid robot movement

Use display, lighting, sounds, etc. to deter cell phone use

Design a microcontroller to interface the systems

Microcontroller

Home Base RF Beacon

Servo Motors

IR Object Detection

RF Signal Detection

Motor Controller

Motor Feedback

Data/ Programming interface

Signal Disruption

Hardware Implementation

Implementation of Subsystems

The Robot

Metal platform from previous project

Two 9FGHD Ferrite Series ServoDisc Motors

Robot Movement

Autonomous Object Detection

Infra-Red Home Base Detection

RF

Programmable Search Pattern Signal Detection Sweep

Identify and approach appropriate signal

Scenario #1

Signal Found

Scenario#2

No Signal Found

Object Detected

No Signal Found

Signal Found

IR Object Detection

Sharp GP2D12

Analog output voltage

Vcc-.3V to .6V based on

distance from object

0cm to 80cm

The Motor

9FGHD Ferrite Series ServoDisc Motor

Input voltage -12V to +12V

Capable of 1.5 N-m continuous torque

Motor Drivers

Microcontroller delivers signal voltage to drivers using PWM

Driver performs DC/DC conversion to step up input signal voltage to -12V to +12V output motor voltage

Motor Encoders

Encoders such as the

HEDS-5500 mounted

on each motor

Signal Detection

Robot Signal Detection

Overview: This part of the robot will detect signals within the GSM frequency-band that will then be translated into data that will control the robots movement in pursuit of a detected strong signal. This will be done by the following devices: Tuned directional antennas RF signal intensity meter Voltage processing component

Tuned Directional Antennas

This component will give directional ordination to the robot to pursue the signal. A Yagi antenna will be used to hone in on the signal.

Antennas Specifications:

GSM: Uplink 890-915MHz and Downlink 935-960Mhz

PCS band: 1.7-1.99 GHz

Directional Capability

Yagi VS Omni directional antennas

RF Signal Intensity Meter

This simplified circuit will take the antenna’s RF signal as an input and will output a voltage that is proportional to the signal’s intensity.

Voltage Processing Component

Feed measured voltage into the micro-controller’s A/D converter.

Have the microcontroller only sample at what is realistic to match the motor’s encoder data.

Store both RF intensity and robot direction data for a full revolution in on-board RAM.

Find peak voltage within data and have robot return to this recorded direction.

Microcontroller

Prototype Board for MSP430-F1611 Multiple A/D converters Expanded RAM to 10K bytes for greater storage capacity PWM capabilities for motor control Good tools and easy debugging Cost effective solution of our application

Power Distribution

Power Distribution and Peripherals

Voltage Variations Driver motors, Lights,

Speakers, Sensors, Circuitry, Display screen

Voltage regulators or converters

Recharging at “home”

Power Distribution and Peripherals-Battery

2 BP7-12 12 V 7Ah Batteries to power the robot

5.94” x 2.56” x 3.98”

6 lbs.

Disruption Handling

Disruption Handling

Robot Modes Hospital Mode

Robot looks for over any amount of time, suggesting a data transmission

Turn off your cell phone! Silent Mode

Robot looks for signal lasting for awhile, suggesting a call vs. a text message

Quiet your phone!

Disruption Handling

Disruption of Call LCD screen for message Lights, sounds Physically disrupt the call?

Home Base

Home Base

Robot will be able to autonomously return to a given “home base” for a variety of reasons: Battery charge level Set time period Called back by us

Home Base

Recharge Station

RF “Beacon”

Data Sync

Home Base –RF “Beacon”

To call the robot home a signal within the robots detection bandwidth will be emitted. Constant frequency within range of detection

device Higher power to override cell phone signals.

Same intelligence used to follow cell phone signals will be used find the home base.

Home Base-Programming

Home Base will be used to reprogram different parameters of the robot such as: Search Pattern Search Time

Risks/Contingencies

Risk/Contingency #1

Risk: It might be impossible to legally physically disrupt the cell phone signal.

Contingency: Robot will ask user to turn off phone via basic display/sounds.

Risk/Contingency #2

Risk: Difficulty to differentiate between cell phone signals and other RF signals.

Contingency: Setup closed environment with little outside interference and use a strong set signal to test tracking ability.

Risk/Contingency #3

Risk: Complexity of artificial intelligence and automation. Object avoidance while tracking signal.

Contingency: Test in empty room to simplify coding.

Risk/Contingency #4

Risk: In areas that RF transmissions are not allowed, our home beacon will not suffice.

Contingency: Program return path or remember path traveled in order to return home.

Scheduling, Costs, and Labor

Prelim Schedule

Milestones

Milestone 1:Robot moves towards test signal

Milestone 2:Programmable search parameters, IR object detection integration, home base construction complete

Expo:Robot and home base fully functional

Cost Estimations

Thank you!

??Questions??