Real-Time Environmental Monitoring: Sensors and Systems

382 Pages·2015·11.053 MB·English

by  Miguel F. Acevedo

Real-Time
Environmental
Monitoring
Sensors and Systems

Real-Time
Environmental
Monitoring
Sensors and Systems
Miguel F. Acevedo
CRC Press
Taylor & Francis Group
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Contents
List of Figures ......................................................................................................xiii
List of Tables .......................................................................................................xxv
Preface ................................................................................................................xxvii
Acknowledgments ............................................................................................xxix
Author .................................................................................................................xxxi
1. Introduction .....................................................................................................1
1.1 Why Is Environmental Monitoring? ................................................1
1.2 Environmental Systems, Ecosystems, and Planet Earth ...............2
1.3 Example ................................................................................................3
1.4 Interactions in the Natural Environment ........................................5
1.5 Human Interactions with the Environment ....................................5
1.6 From Measuring to Knowing: Analysis and Modeling ................6
1.7 Continuous Real-Time Monitoring ...................................................7
1.8 Data Management and the World Wide Web .................................7
1.9 Interdisciplinary ..................................................................................8
1.10 Scales .....................................................................................................8
1.11 Sampling...............................................................................................9
1.11.1 Detection Limits ...................................................................9
1.11.2 Rounding Numbers .............................................................9
1.11.3 Precision and Accuracy .......................................................9
1.12 Ground-Based, Airborne, and Spaceborne Platforms .................11
1.13 More on Applications .......................................................................11
1.13.1 Examples of Programs and Agencies .............................12
Supplementary Reading ...............................................................................13
Exercises ..........................................................................................................13
Section I From Sensors to Systems
2. Sensors and Transducers: Basic Circuits .................................................17
2.1 Principles of Electrical Quantities ..................................................17
2.2 Circuits: Nodes and Loops ..............................................................21
2.3 Measuring Voltages, Currents, and Resistances ...........................25
2.4 Sensors ................................................................................................28
2.5 From Sensors to Transducers ..........................................................29
2.6 Sensor Specifications: Static .............................................................29
2.7 Resistive Sensors ...............................................................................30
2.8 Example: From a Light Sensor to a Light Transducer ..................30
2.9 Example: From Thermistor to Temperature Transducer .............39
v
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2.10 Example: Temperature Transducer for Air, Soil, and Water .........46
2.11 Example: Thermocouples .................................................................49
2.12 Examples: Using Thermocouples....................................................54
Supplementary Reading ...............................................................................54
Exercises ..........................................................................................................55
3. Sensors and Transducers: Bridge Circuits...............................................57
3.1 Introduction .......................................................................................57
3.2 Balanced Source Voltage Divider ....................................................57
3.3 One-Sensor Circuit: Quarter-Bridge ..............................................63
3.4 Two-Sensor Circuit: Half-Bridge .....................................................64
3.5 Two-Sensor Having Opposite Effect: Half-Bridge .......................65
3.6 Four Sensor Circuit: Full Bridge .....................................................66
3.7 Zero Adjust and Range Adjust ........................................................69
3.8 Sensor Specifications ........................................................................69
3.9 Electrochemical Sensors ..................................................................71
3.10 Example: Dynamic Specifications and a Potentiometer-Based
Wind Direction .........................................................................................74
3.11 Dielectric Properties .........................................................................74
3.12 Example: Piezoelectric Sensors .......................................................76
3.13 Example: Soil Tensiometer ...............................................................76
Exercises ..........................................................................................................77
4. Signal Conditioning and Analog-to-Digital Converters .....................79
4.1 Introduction .......................................................................................79
4.2 Operational Amplifiers ....................................................................79
4.3 Linearization of the Bridge Circuit Output ...................................82
4.4 Common-Mode Rejection ................................................................83
4.5 Instrumentation Amplifier ..............................................................84
4.6 Spectrum ............................................................................................85
4.7 Noise ...................................................................................................86
4.8 Electric Field and Electrostatic Shielding ......................................87
4.9 Isolation ..............................................................................................89
4.10 Cold-Junction Compensation ..........................................................89
4.11 Analog-to-Digital Converter............................................................90
4.12 Current Loop: 4–20 mA ....................................................................92
4.13 Pulse Sensors .....................................................................................94
Exercises ..........................................................................................................95
5. Data Acquisition Systems ...........................................................................97
5.1 Introduction .......................................................................................97
5.2 Dataloggers ........................................................................................97
5.3 Applications in Environmental Monitoring .................................99
5.4 Analog Channels...............................................................................99
5.5 Real-Time Clock ...............................................................................100
Contents vii
5.6 Communications with a Datalogger ............................................102
5.6.1 Baud Rate and Serial Communication ...........................102
5.6.2 Data, Parity, and Stop (D/P/S) Bits..................................102
5.7 RS-232 Standard ..............................................................................103
5.8 SDI-12 ................................................................................................106
5.9 Conditions and Enclosures ............................................................106
5.10 Datalogger Example: CR1000 ........................................................108
5.11 VoltSE ................................................................................................113
5.12 VoltDiff .............................................................................................113
5.13 BrHalf ................................................................................................113
5.14 BrFull .................................................................................................114
5.15 PulseCount .......................................................................................114
5.16 Supervisory Control and Data Acquisition .................................117
Exercises ........................................................................................................117
6. Single-Board Computers and Microcontrollers ...................................119
6.1 Introduction .....................................................................................119
6.2 Computer Organization and Architecture ..................................119
6.3 Single-Board Computers ................................................................120
6.4 ARM Architectures .........................................................................121
6.5 SBC Based on ARM Processor: Example .....................................121
6.6 System on a Chip .............................................................................121
6.7 SBC Example: Raspberry Pi ...........................................................122
6.8 Microcontrollers ..............................................................................123
6.9 MCU Example .................................................................................125
6.10 In-Circuit Serial Programming .....................................................125
6.11 MCU-Based SBC Example: Arduino ............................................126
6.12 Comparing SBCs: TS-7400, Raspberry Pi, Arduino Uno ...........127
6.13 MCUs as DAS...................................................................................128
6.14 Example: Arduino Programming .................................................129
6.15 Example: Using Flash Memory for Datalogging
with Arduino ...............................................................................133
6.16 Example: Using a Datalogger Shield for Arduino ......................136
6.17 Example MCU-Based SBC .............................................................137
Exercises ........................................................................................................138
7. Wireless Technologies and Telemetry ....................................................139
7.1 Introduction .....................................................................................139
7.2 Wave Concepts ................................................................................139
7.3 Radio Wave Spectrum ....................................................................140
7.4 Radio Wave Propagation ................................................................141
7.5 Propagation Models ........................................................................143
7.5.1 Free-Space Propagation Model ........................................143
7.5.2 Two-Ray Propagation Model ...........................................145
7.6 Phase Shift ........................................................................................146
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7.7 Fresnel Zones ...................................................................................147
7.8 Absorption .......................................................................................148
7.9 Radio Frequency Cables .................................................................148
7.10 Power in dBm ...................................................................................149
7.11 Antennas ..........................................................................................149
7.12 Fade Margin .....................................................................................150
7.13 Polarization ......................................................................................151
7.14 Modulation: Digital Signals ...........................................................151
7.15 Multiplexing.....................................................................................152
7.16 Spread Spectrum .............................................................................153
7.17 Wi-Fi ..................................................................................................153
7.18 Example: Low-Cost Wi-Fi Radio ...................................................154
7.19 Example: Establishing a Wi-Fi Link to Connect
a Weather Station to the Internet ..................................................155
7.20 Cellular Phone Network ................................................................157
7.21 Argos .................................................................................................158
Exercises ........................................................................................................158
8. Wireless Sensor Networks ........................................................................159
8.1 Introduction .....................................................................................159
8.2 WSN Nodes ......................................................................................159
8.2.1 Example of a Two-Module Sensor Node:
Crossbow IRIS and MDA .................................................162
8.2.2 Example of an Integrated Sensor Node: Moteinos .......163
8.3 Networks: OSI Model .....................................................................163
8.4 Media Access Control .....................................................................164
8.5 Multihop Wireless Communication .............................................164
8.6 Network Protocol for Environmental Monitoring .....................165
8.7 Radio Propagation and WSN ........................................................166
8.8 Example of Radio Propagation Experiments ..............................167
8.9 Example: WSN for Soil Moisture in a Hardwood
Bottomland Forest ...........................................................................168
8.10 WSN: Energy Scavenging ..............................................................172
Exercises ........................................................................................................173
9. Power .............................................................................................................175
9.1 Introduction .....................................................................................175
9.2 Photovoltaic ......................................................................................175
9.3 Solar Radiation and Efficiency ......................................................177
9.4 Solar Cell Model ..............................................................................179
9.5 From Cell to Module .......................................................................186
9.6 Shading and Bypass Diode ............................................................187
9.7 Load and Power ...............................................................................188
Contents ix
9.8 Maximum Power Point Tracking ..................................................188
9.9 Efficiency and Performance ...........................................................190
9.10 Tilting the Panel ..............................................................................191
9.11 Atmospheric Effects ........................................................................193
9.12 Sun Path ............................................................................................196
9.13 Impact of Temperature on Solar Panel .........................................201
9.14 Example: Powering a Remote Monitoring Station .....................203
Exercises ........................................................................................................203
10. Databases and Web Access .......................................................................205
10.1 Introduction .....................................................................................205
10.2 Examples of Raw Data Format ......................................................206
10.3 Relational DBs .................................................................................207
10.4 Structural Query Language...........................................................212
10.5 Extensible Markup Language .......................................................215
10.5.1 Example of Nested Elements ..........................................216
10.5.2 Example DTD ...................................................................217
10.5.3 Example XML Schema ....................................................217
10.6 Backup ..............................................................................................219
10.7 Web Services ....................................................................................219
10.8 Metadata, Standards, Interoperability, and Preservation ............220
10.9 Example: Data Collected from Distributed Sensor Systems ........221
Exercises ........................................................................................................222
Section II Applications to Atmospheric
Processes, Water Resources, Terrestrial
Ecosystems, and Wildlife Monitoring
11. Atmospheric Monitoring ..........................................................................225
11.1 Introduction .....................................................................................225
11.2 Earth’s Atmosphere.........................................................................225
11.3 Vertical Structure ............................................................................226
11.4 Atmosphere–Near-Surface Air Quality .......................................227
11.5 Particulate Matter............................................................................228
11.6 Stations .............................................................................................229
11.7 Optical Devices................................................................................229
11.7.1 Photodiode ........................................................................229
11.7.2 Linear Photodiode Array and Charge Coupled
Devices ...........................................................................229
11.7.3 Gratings .............................................................................230
11.7.4 Dispersive Spectrometers ...............................................230
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11.7.5 Photomultiplier Tubes .................................................230
11.7.6 Beam Splitter ................................................................232
11.7.7 Fourier Transform Interferometer .............................232
11.7.8 Fiber Optics ..................................................................233
11.8 Measurement Methods Using Samples in Closed Path ..........233
11.9 Optical Absorption Spectroscopy...............................................234
11.10 Chemiluminscent Analyzer ........................................................235
11.11 Fluorescence ...................................................................................237
11.12 Nondispersive Infrared ................................................................237
11.13 Measurement Methods Using Open Path .................................239
11.14 Total Column Measurements ......................................................240
11.14.1 Optical Absorption Spectroscopy .............................240
11.14.2 Differential Optical Absorption Spectroscopy .......241
11.15 Atmosphere–Weather ...................................................................242
11.15.1 Air Temperature ..........................................................242
11.15.2 Rain ................................................................................242
11.15.3 Relative Humidity .......................................................243
11.15.4 Solar Radiation .............................................................243
11.15.5 Wind Velocity and Direction: Sonic
Anemometers ............................................................244
11.16 Example: Measuring UV and TC Ozone Concentration
by OAS and DOAS ........................................................................247
12. Hydrology, Hydrodynamics, Water Quality, and Aquatic
Ecosystems ...................................................................................................251
12.1 Introduction ...................................................................................251
12.2 Water ...............................................................................................251
12.3 Water Level and Depth ................................................................252
12.4 Water Velocity and Flow ..............................................................253
12.5 Water Quality Parameters............................................................255
12.6 Water Quality Sensors ..................................................................255
12.6.1 pH and ORP Sensors ...................................................255
12.6.2 Dissolved Oxygen Sensor ..........................................256
12.6.3 Electrical Conductivity ...............................................256
12.6.4 Irrigation Water............................................................259
12.6.5 Salinity ..........................................................................260
12.6.6 Total Dissolved Solids .................................................260
12.6.7 Turbidity .......................................................................261
12.6.8 Temperature .................................................................263
12.6.9 Fluorometer ..................................................................263
12.6.10 Multiple Parameter Probes .........................................264
12.7 Productivity and Respiration ......................................................265
12.8 Light as a Function of Depth .......................................................266
12.9 Automated Real-Time Biomonitoring ........................................266