Mid-Semester PresentationMid-Semester Presentation

Senior Design 1Senior Design 1

October 8, 2009October 8, 2009

Randall Vaughan

Oscillator Interface

Layout and Design

Electrical Engineering

Caroline Quijano

Op-Amp Configuration

Layout and Design

Electrical Engineering

Zach Jordan

Op-Amp ConfigurationPhase Shift Detection

Computer Engineering

Jonathan Lynch

Oscillator InterfaceWebsite DesignCircuit Board Production

Electrical Engineering

ProblemProblem SolutionSolution ConstraintsConstraints

• TechnicalTechnical• PracticalPractical

AlternativesAlternatives ProgressProgress

Dr. Jack Liu of the Department of Dr. Jack Liu of the Department of Forestry Products requires the use of Forestry Products requires the use of a portable RF moisture content a portable RF moisture content sensorsensor

Needs a smaller, inexpensive, Needs a smaller, inexpensive, repackage of his patented prototype repackage of his patented prototype

The moisture content sensor will apply a high frequency sine wave using a XR2206 waveform generator, two PS-05 48V power supplies, and a PA78 350V operational amplifier .

The resultant phase shift and attenuation measurements between the applied and received signal will be used to compute the moisture content.

MC= -11403+1665.637Att – 80.843Att^2 + 1.305Att^3 + 0.571Phase^2

Power Supply

Operational Amplifier

PIC 24Waveform Generator

LCD Screen

Transmitting/Receiving

Sensors

Technical ConstraintsTechnical Constraints

Practical ConstraintsPractical Constraints

Constraint Description

Voltage LevelThe signal applied to the sensors must measure 80V (+/- 5V) peak-to-peak.

Frequency The sensor must produce a 250 kHz (+/- 5 kHz) sine wave.

InterfaceThe device must have a simple user interface in order to display its measurements.

Data LoggingThe device must be able to store at least 130 kilobytes of moisture content readings.

Sensor ArrayThe device must use seven 4 in. by 4 in. sensors configured in an array.

Type Constraint Description

Environmental DurabilityThe device must be able to withstand various industrial conditions such as dust and electrical noise.

Health and Safety

SafetyUser contact with high voltage signals must be prevented.

Sensor must Sensor must withstand debris, withstand debris, electrical noise, electrical noise, and moistureand moisture

Sealed, electrically Sealed, electrically shielded, rugged shielded, rugged housinghousing

[5]

Isolated high Isolated high voltagesvoltages

Partition that Partition that separates gap separates gap from user from user interfaceinterface

Appropriate Appropriate warning labels warning labels displayeddisplayed

[6]

Power SuppliesPower Supplies

Sine Wave GenerationSine Wave Generation

Operational AmplifiersOperational Amplifiers

Phase Shift DetectionPhase Shift Detection

Mean Well PS-05Mean Well PS-05• Pros: Supplies +/-48 volts, Inexpensive, Easily-Accessible, Pros: Supplies +/-48 volts, Inexpensive, Easily-Accessible,

Low Power Dissipation, AC/DC SwitchingLow Power Dissipation, AC/DC Switching• Cons: Requires Separate CablesCons: Requires Separate Cables

Charge PumpCharge Pump• Pros: High Efficiency, Electrically-Simple CircuitsPros: High Efficiency, Electrically-Simple Circuits• Cons: High Current DrawCons: High Current Draw

DC/DC ConverterDC/DC Converter• Pros: Regulates Output VoltagePros: Regulates Output Voltage• Cons: Several Sub-Circuits (each with its own voltage Cons: Several Sub-Circuits (each with its own voltage

level requirement different from the external source)level requirement different from the external source)

XR2206 Waveform GeneratorXR2206 Waveform Generator• Pros: Frequency easily set by a resistor and capacitor, excellent Pros: Frequency easily set by a resistor and capacitor, excellent

temperature stability (20ppm/deg C)temperature stability (20ppm/deg C)• Cons: Requires a minimum 10V supply voltageCons: Requires a minimum 10V supply voltage

DS1077 Programmable OscillatorDS1077 Programmable Oscillator• Pros: I2C Interface, Inexpensive, Dual Output, Programmable Pros: I2C Interface, Inexpensive, Dual Output, Programmable

Frequencies 8.1kHz – 133MHzFrequencies 8.1kHz – 133MHz• Cons: Does not output a sine waveCons: Does not output a sine wave

Analog Edge Sine Wave GenerationAnalog Edge Sine Wave Generation• Pros: Simple Circuit, InexpensivePros: Simple Circuit, Inexpensive• Cons: Sine Wave Distortion, Square Wave GenerationCons: Sine Wave Distortion, Square Wave Generation

Resonant CrystalResonant Crystal• Pros: Very accurate, High precision, StablePros: Very accurate, High precision, Stable• Cons: Comes with a fixed frequency, unchangeable Cons: Comes with a fixed frequency, unchangeable

PA78 350V Op-AmpPA78 350V Op-Amp• Pros: Has High Voltage Specification, High Slew Rate for Pros: Has High Voltage Specification, High Slew Rate for

Phase Shift, Low Idle CurrentPhase Shift, Low Idle Current

OPA445 90V Op-AmpOPA445 90V Op-Amp• Pros: Meets minimum requirements for voltage Pros: Meets minimum requirements for voltage

specificationspecification• Cons: Low slew rateCons: Low slew rate

OPA453 80V 50mA Op-AmpOPA453 80V 50mA Op-Amp• Pros: Has high slew ratePros: Has high slew rate• Cons: Does not meet rail-to-rail voltage specificationCons: Does not meet rail-to-rail voltage specification

Zero Crossing Zero Crossing CircuitsCircuits

Logic GatesLogic Gates

[7]

AugustAugust SeptemberSeptember OctoberOctober NovemberNovember

ResearchResearch

Hardware Hardware

DesignDesign

PrototypingPrototyping

TestingTesting

Programmed DS1077 Oscillator to Programmed DS1077 Oscillator to 250 kHz250 kHz

Ordered Power SuppliesOrdered Power Supplies

PA78 350V Operational AmplifierPA78 350V Operational Amplifier• Designed alternative feedback loopsDesigned alternative feedback loops

PIC 24

DS1077 Programmable Oscillator

XR2206 Waveform Generator

Mean Well Mean Well PS-05PS-05

[1] United States of America. Federal Communications Commission. [1] United States of America. Federal Communications Commission. Code of Code of Federal Regulations, Title 47, Part 15.Federal Regulations, Title 47, Part 15. Washington, D.C.: Federal Communications Washington, D.C.: Federal Communications Commission, 2008. Commission, 2008.

[2] Panel Layup Operations, by Phil Mitchell, Raleigh, NC. [Online] Available: [2] Panel Layup Operations, by Phil Mitchell, Raleigh, NC. [Online] Available: http://www.ces.ncsu.edu/nreos/wood/RMOG/Adobe/Panel.pdfhttp://www.ces.ncsu.edu/nreos/wood/RMOG/Adobe/Panel.pdf..

[3] Forestry Facts: Guide for Using the Oven-Dry Method for Determining the [3] Forestry Facts: Guide for Using the Oven-Dry Method for Determining the Moisture Content of Wood, by R.S Boone and E.M. Wengert, Madison, Wisconsin, Moisture Content of Wood, by R.S Boone and E.M. Wengert, Madison, Wisconsin, 1998. [Online] Available:1998. [Online] Available:

http://forest.wisc.edu/extension/Publications/89.pdfhttp://forest.wisc.edu/extension/Publications/89.pdf..

[4] Wood Products Notes: Methods of Moisture Content Measurement in the [4] Wood Products Notes: Methods of Moisture Content Measurement in the Lumber and Furniture Industries, by Phil Mitchell, Raleigh, NC. [Online]Available: Lumber and Furniture Industries, by Phil Mitchell, Raleigh, NC. [Online]Available: http://www.ces.ncsu.edu/nreos/wood/wpn/methods_moisture.htmhttp://www.ces.ncsu.edu/nreos/wood/wpn/methods_moisture.htm. .

[5] Google Images. 2009. [5] Google Images. 2009. http://www.waltsense.com/storage/articles/20090429_finger-in-socket.jpg.http://www.waltsense.com/storage/articles/20090429_finger-in-socket.jpg.

[6] Microsoft Office Online, Clip Art. 2009. [6] Microsoft Office Online, Clip Art. 2009. http://office.microsoft.com/en-us/clipart/results.aspx?qu=warning&sc=20http://office.microsoft.com/en-us/clipart/results.aspx?qu=warning&sc=20..

[7] Phase Shift. Algebra 2 Trig., by Donna Roberts. Copyright 1998-2009. [7] Phase Shift. Algebra 2 Trig., by Donna Roberts. Copyright 1998-2009. http://www.regentsprep.org/Regents/math/algtrig/ATT7/phaseshift.htmhttp://www.regentsprep.org/Regents/math/algtrig/ATT7/phaseshift.htm..