Mid-Semester Presentation Senior Design 1 October 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 Configuration Phase Shift Detection Computer Engineering Jonathan Lynch Oscillator Interface Website Design Circuit Board Production Electrical Engineering

 Problem  Solution  Constraints TechnicalTechnical PracticalPractical  Alternatives  Progress

 Dr. Jack Liu of the Department of Forestry Products requires the use of a portable RF moisture content sensor  Needs a smaller, inexpensive, 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= Att – Att^ Att^ Phase^2

Power Supply Operational Amplifier PIC 24 Waveform Generator LCD Screen Transmitting/ Receiving Sensors

 Technical Constraints  Practical Constraints

 Sensor must withstand debris, electrical noise, and moisture  Sealed, electrically shielded, rugged housing [5]

 Isolated high voltages  Partition that separates gap from user interface  Appropriate warning labels displayed [6]

 Power Supplies  Sine Wave Generation  Operational Amplifiers  Phase Shift Detection

 Mean Well PS-05 Pros: Supplies +/-48 volts, Inexpensive, Easily- Accessible, Low Power Dissipation, AC/DC SwitchingPros: Supplies +/-48 volts, Inexpensive, Easily- Accessible, Low Power Dissipation, AC/DC Switching Cons: Requires Separate CablesCons: Requires Separate Cables  Charge Pump Pros: High Efficiency, Electrically-Simple CircuitsPros: High Efficiency, Electrically-Simple Circuits Cons: High Current DrawCons: High Current Draw  DC/DC Converter Pros: Regulates Output VoltagePros: Regulates Output Voltage Cons: Several Sub-Circuits (each with its own voltage level requirement different from the external source)Cons: Several Sub-Circuits (each with its own voltage level requirement different from the external source)

 XR2206 Waveform Generator Pros: Frequency easily set by a resistor and capacitor, excellent temperature stability (20ppm/deg C)Pros: Frequency easily set by a resistor and capacitor, excellent temperature stability (20ppm/deg C) Cons: Requires a minimum 10V supply voltageCons: Requires a minimum 10V supply voltage  DS1077 Programmable Oscillator Pros: I2C Interface, Inexpensive, Dual Output, Programmable Frequencies 8.1kHz – 133MHzPros: I2C Interface, Inexpensive, Dual Output, Programmable Frequencies 8.1kHz – 133MHz Cons: Does not output a sine waveCons: Does not output a sine wave  Analog 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 Crystal Pros: Very accurate, High precision, StablePros: Very accurate, High precision, Stable Cons: Comes with a fixed frequency, unchangeableCons: Comes with a fixed frequency, unchangeable

 PA78 350V Op-Amp Pros: Has High Voltage Specification, High Slew Rate for Phase Shift, Low Idle CurrentPros: Has High Voltage Specification, High Slew Rate for Phase Shift, Low Idle Current  OPA445 90V Op-Amp Pros: Meets minimum requirements for voltage specificationPros: Meets minimum requirements for voltage specification Cons: Low slew rateCons: Low slew rate  OPA453 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 Circuits  Logic Gates [7]

AugustSeptemberOctoberNovemberResearch HardwareDesign Prototyping Testing

 Programmed DS1077 Oscillator to 250 kHz  Ordered Power Supplies  PA78 350V Operational Amplifier Designed alternative feedback loopsDesigned alternative feedback loops

PIC 24

DS1077 Programmable Oscillator XR2206 Waveform Generator

Mean Well PS-05

 [1] United States of America. Federal Communications Commission. Code of Federal Regulations, Title 47, Part 15. Washington, D.C.: Federal Communications Commission,  [2] Panel Layup Operations, by Phil Mitchell, Raleigh, NC. [Online] Available:  [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, [Online] Available:  [4] Wood Products Notes: Methods of Moisture Content Measurement in the Lumber and Furniture Industries, by Phil Mitchell, Raleigh, NC. [Online]Available:  [5] Google Images  [6] Microsoft Office Online, Clip Art us/clipart/results.aspx?qu=warning&sc=20.  [7] Phase Shift. Algebra 2 Trig., by Donna Roberts. Copyright