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 MSP A/D Input Tuned Yagi Antenna Motor Drivers Data/ Programming interface Signal Disruption Hardware Implementation Low Noise Amplifier Diode Rectification Circuit Sharp IR Detectors (3) I2C Interface Digital Compass Module PWM Signal Outputs ServoDisc Motors JTAG Interface

Software Flow Diagram System Ok no yes no Move Forward Turn 90 o Object? yes Timer Going? Try to detect signal Rotated 360 o ? Read Compass and Antenna Value Find Strong Signal? yes 2 no Turn to match degrees of strongest signal yes Forward Reached Object? no Signal DisruptionRotate 180 o 1 Count=2? no Signal still there? Count yes no yes no yes

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 No Signal Found Object Detected No Signal Found Signal Found

Wave Reflection Signal waves reflect off of Metal Surfaces Constructive Phase alignment creates false positives Solution: Continue to monitor signal while approaching source.

Metal Surface Reflected Waves Constructive Phase Destructive Phase Signal Found Signal Present Signal Lost False Positive! Signal Found Scenario#2

The Motor 9FGHD Ferrite Series ServoDisc Motor Input voltage -12V to +12V Capable of 1.5 N-m continuous torque

Motor Drivers LMD18200t

Sign/Magnitude PWM Control

PWM Control Circuitry

Digital Compass Module I2C 2-Wire Serial Interface 3.3v supply voltage 1/2 degree heading resolution Firmware Included

I2C Module

I2C Communication

Compass Command Bytes

Getting compass data Heading Mode: The heading output data will be the value in tenths of degrees from zero to 3599 and provided in binary format over the two bytes.

Signal Detection

Robot Signal Detection Overview: This part of the robot will detect signals within the GSM frequency-band that will then be amplified by a Low Noise Amplifier, rectified into a DC voltage, then finally interpreted by our microcontrollers A/D converter. This will be done by the following devices: Tuned directional antenna RF signal amplifier and diode rectifier MSP430 A/D Converter

Tuned Directional Antenna 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 MHz and Downlink Mhz PCS band: GHz

Antenna Capability Reverse-Polarity BNC-PlugAdapter to Standard BNC-Plug

Signal Amplification 50 Ω Low Noise Amplifier High output Gain Low noise figure Operates in the frequency band we require

Non-rectified RF Signal Data Message Phone 65 ° out of line Voice Call *Volt scale is 100mV *Signal is being boosted by LNA Did someone say this was impossible?

RF Signal Rectification Circuit 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. LNA will boost signal gain to a readable voltage level. Diodes will rectify signal to a DC voltage with minimum losses.

Voltage Processing Feed measured voltage into the micro-controller’s A/D converter. Have the microcontroller will only sample this A/D at times of signal searching. Store both RF intensity and robot degree of 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, UART, and I2C peripherals 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

Functional Block Diagram

AD Converter We will be using the 12 Bit AD converter peripheral. The ADC will convert voltages into integers between 0 and 4095 relative to the voltage levels. We will be using a reference voltage of 1.5V as it gives us more resolution and we will not be inputting anything higher than that.

ADC12 Module

IR Object Detection Sharp GP2D12 Analog output voltage distance from object 10cm to 80cm Optimal Vcc V

IR Sensor Voltage Output Curve The IR sensors have a non- linear output voltage curve with respect to distance. Range is from 10 to 80cm with higher voltages representing shorter distances. 10cm-2.6v 80cm-.4V >80cm-.25V

Home Base If time permits we will still implement a home base. Home Base will generate a signal to call robot home to: Recharge Be reprogrammed Signal will be made by a function generator in antenna frequency range. More testing required to see what kind of information antenna will give us.

Power Distribution

Voltage Variations 5 V LCD Screen IR Detectors 3.3 V Microcontroller 12 V Motor Drivers LNA Voltage Regulators LM1117 Regulate to 5 V, 3.3 V

The Battery 2 BP V 7Ah Batteries to power the robot 5.94” x 2.56” x 3.98” 6 lbs.

Opto-isolators HPCL-3150 Will be used for isolation and level shifting for PWM, direction/brake signals

Disruption Handling

LCD Screen Serial Enabled 16x2 LCD - Black on Green 10k Pot to adjust contrast

Schematic

PCB

Scheduling, Costs, and Labor

Updated Schedule

Separation of Tasks Programming of Microcontroller – Travis and Ben PCB Design – Carey Motor driver control – Bill and Ben Antenna – Travis, Bill LCD screen – Ben and Carey

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 ItemPriceQuantityTotal Yagi Antenna Battery29.61 IR Sensors Motor drivers5420 Dev Board and Compass LNA and connectors1601 E store(perf board and headers)201 Total so far $453 PCB MSP chip201 LCD screen251 IR sensors Miscellaneous1001 Estimated Total $755

Thank you! ??Questions??