ITMD2 Contents

Inside the METAL DETECTOR
2nd Edition

ISBN 978-0-9858342-0-3
Publication date: May 2015
250 pages

Introduction

Chapter 1: History of the Metal Detector
The People
The Applications
The Companies

Chapter 2: The BFO Principle

Chapter 3: Designing a BFO Detector
Reference Oscillator Design
Search Oscillator Design
Mixer and Detector Design
Headphone Amplifier
The Complete BFO Detector
Using Oscillator Harmonics
Construction Details

Chapter 4: A Simple Probe That Works!
Search Oscillator
Automatic Tracking Circuit
Construction Details

Chapter 5: Induction & Coils
Magnetic Fields
Induction
Induction Balance
Eddy Currents
Search Coils
Mineralization Effects

Chapter 6: Principles of Induction Balance
Transmit Frequency
What the Experts Say
So What's Best?
Power Supply
Evaluation of Initial Design Decisions

Chapter 7: Target Discrimination
Phase Demodulation
Motion Versus Non-motion
Discrimination With an Analog Detector

Chapter 8: Transmit-Receive Detector
Transmit Oscillator
RX Amplifier
Audio Output
Power Supply
Testing
Construction Details

Chapter 9: Designing an IB Detector
Acronyms
Stabilized Power Supply
Transmit Oscillator
Receiver Preamp
Designing a VLF IB Detector with GEB
GEB and DISC sampling
CMOS Analog Switches
Motion Mode of Detection
Audio Oscillator, Chopper and Amplifier
A Little More Info On Discrimination
Automatic Battery Check Circuit
Battery Pack
The Completed Prototype
Initial Setup Procedure
Real World Testing
But Can We Do Better?
Improving the Design
Comparator Operation
Detector Calibration
Real World Testing (again)
In Conclusion
Construction Details

Chapter 10: IB Coil Experiments
Experiment #1: MD-3030 10" Concentric Coil
Experiment #2: Fisher M-scope 11" Concentric Coil
Experiment #3: Garrett Crossfire 8" Concentric Coil
Experiment #4: Troy 9" Concentric Coil
Experiment #5: Viking 6DX Double-D Coil
Constructing Homemade IB Coils
Double-D Coil Experiment
Double-O Coil Experiment
Concentric Coil Experiment
Omega Coil Experiment
Conclusion
Step-by-Step Instructions for Constructing a DD Coil

Chapter 11: Pulse Induction Principles
PI Transmit
PI Front End
Sampling
Digging in Deeper
Damping Resistor

Chapter 12: Pulse Induction Designs
PI Design 1
PI Design 2
PI Design 3
PI Design 4
Bonus: PI Design 5
Advanced Topics
Power Supply
Preamp
Sampling
Ground Balance
Coils
Really Advanced Topics
Construction Details --- PI-1
Construction Details --- PI-2
Construction Details --- PI-3
Construction Details --- PI-4

Chapter 13: Loose Ends
Multi-frequency Design
Myths & Fallacies
Is it an antenna?
The Halo Effect
Metal or Plastic Stem Bolt?
Electrostatic Shielding
Power Output
Coil Sensitivity
The Concentric Ring Experiment
Nuances in International Electronics
Component Marking Standard
Electromagnetic Terminology
PC Boards

Appendix A: Air-Cored Coil Calculator
Javascript Example
Accuracy

Appendix B: Resources
Web Sites
Books
Magazine Articles
Patents

Index