Cover
Introduction
1. Who Will Benefit Most from This Book
2. Sourcing Parts and Supplemental Materials
3. Special Features
4. What Does This Book Cover?
Part I: IoT and Electricity Basics
1. CHAPTER 1: IoT and Electronics
  1. IoT in a Nutshell
  2. Parts of an IoT System
  3. Challenges in Implementing IoT
  4. IoT into the Future
2. CHAPTER 2: Electricity: Its Good and Bad Behavior
  1. Try This: Creating Some Static
  2. Electricity at an Atomic Level
  3. Conductors and Insulators
  4. Characteristics of Electricity
  5. Induction and Conduction
  6. Try This: Creating a Simple Breadboard Circuit
  7. The Basic Circuit
  8. Circuit Protection Devices
3. CHAPTER 3: Symbols and Diagrams
  1. Types of Diagrams
  2. Schematic Symbols
  3. So Many Switches!
  4. Drawing Your Circuit
  5. Try This: Adding a Switch and Creating a Schematic
4. CHAPTER 4: Introduction to the Arduino Uno
  1. What Is Arduino?
  2. The Arduino Board
  3. Analog vs. Digital
  4. The Arduino IDE
  5. Try This: Creating a Simple Arduino-Controlled Circuit
  6. Try This: Changing Pins
  7. Try This: Creating Arduino Running Lights
  8. Try This: Adding a Switch to Your Circuit
  9. Try This: Using the Serial Monitor
5. CHAPTER 5: Dim the Lights
  1. Using a Multimeter
  2. Try This: Repurposing a Power Supply
  3. Measuring Voltage, Current, and Resistance
  4. Try This: Dimming the Lights
  5. Try This: Measuring Circuit Values
  6. Using Arduino to Measure Electricity
  7. Try This: Using an Arduino Voltmeter
  8. Try This: Using an Arduino Ohmmeter
  9. Try This: Using an Arduino Ammeter
  10. Try This: Using an Arduino Continuity Tester
  11. Try This: Building a Dimmable Arduino Camp Light
  12. Soldering, Perfboards, and Shrink Tubing
6. CHAPTER 6: Feel the Power
  1. Watt’s Law and the Power Wheel
  2. Watts and Horsepower
  3. Battery Power
  4. The Other Resistor Value
  5. Wattmeters
  6. Try This: Using an Arduino Wattmeter
7. CHAPTER 7: Series and Parallel Circuits
  1. Series, Parallel, and Complex Circuits
  2. Try This: Testing Series and Parallel Configurations
  3. Calculating Values in Series and in Parallel
  4. Sources in Series and Parallel
  5. Try This: Calculating Circuit Values
Part II: Using Common Components
1. CHAPTER 8: Diodes: The One-Way Street Sign
  1. Try This: Creating a Simple Polarity Tester
  2. Determining Anode and Cathode
  3. Types of Diodes
  4. Try This: Using a Seven-Segment LED
2. CHAPTER 9: Transistors
  1. Try This: Using a Transistor as an Amplifier
  2. The Purpose of Transistors
  3. Types of Transistors
  4. Try This: Using a Transistor as a Switch
3. CHAPTER 10: Capacitors
  1. A Quick Look at Capacitors
  2. Try This: Creating a Time Delay Circuit
  3. Capacitor Uses
  4. Try This: Creating an Astable Multivibrator
  5. Try This: Using Capacitors in Series and Parallel
4. CHAPTER 11: The Magic of Magnetism
  1. The Electricity/Magnetism Relationship
  2. Try This: Building an Electromagnet
  3. Magnetism in Circuits
  4. Relays
  5. Try This: Building a Relay Oscillator
  6. Try This: Setting Up an Emergency Lighting System
5. CHAPTER 12: Electricity's Changing Forms
  1. Try This: Creating a Water Alarm
  2. Common Transducers
  3. Try This: Creating a Night-Light Circuit
  4. Try This: Creating an Arduino Laser Security System
6. CHAPTER 13: Integrated Circuits and Digital Logic
  1. Integrated Circuits
  2. Try This: Creating an Astable Multivibrator
  3. Operational Amplifiers
  4. Digital Logic
  5. Try This: Exploring AND and OR Gates
  6. Logic Probes and Oscilloscopes
Part III: More Please
1. CHAPTER 14: Pulse Width Modulation
  1. Pulse Width Modulation Explained
  2. Try This: Using a PWM LED Dimmer
  3. Try This: Using a PWM Motor Control
  4. Try This: Trying PWM and an Arduino
2. CHAPTER 15: Sources of Electricity
  1. Chemical Reactions
  2. Try This: Making a Thermocouple
  3. Light
  4. Try This: Displaying PV Output on an Arduino
  5. Friction
  6. Magnetism
  7. Pressure
  8. Wrapping It Up
3. CHAPTER 16: Transformers and Power Distribution
  1. What Is a Transformer?
  2. Try This: Verifying Transformer Output
  3. Alternating Current Values
  4. Power Distribution Using Transformers
4. CHAPTER 17: Inverters and Rectifiers
  1. Inverters vs. Rectifiers and Their Uses
  2. Construction of Inverters
  3. Try This: Filtering a Circuit
  4. Construction of Rectifiers
  5. Single-Phase vs. Three-Phase Power
  6. Try This: Building a Small Variable Power Supply
5. CHAPTER 18: Radio Waves and Tuned Circuits
  1. Radio Waves
  2. Try This: Building a Radio Receiver
  3. Making Waves
  4. Try This: Building an Arduino FM Radio
  5. Tuned Circuits
Part IV: Putting the I in IoT
1. CHAPTER 19: Connecting Your Circuits to the Cloud
  1. The Arduino IoT Cloud
  2. Try This: Setting Up Your Device
  3. Try This: Using Things, Properties, and Widgets
2. CHAPTER 20: Just for Fun
  1. Electronic Fabrics and Wearables
  2. Try This: Lighting Up a Teddy Bear
  3. Paper Circuits
  4. Try This: Creating a Conductive Paint Circuit
  5. Try This: Creating a Copper Tape Circuit
  6. Try This: Building Squishy Circuits
3. CHAPTER 21: What's Next?
  1. The World Is Your Oyster
  2. Recommended Reading and Resources
  3. Words of Encouragement
Index
End User License Agreement

List of Illustrations

Chapter 1
1. Figure 1.1: An IoT system
Chapter 2
1. Figure 2.1: Bending water
2. Figure 2.2: Atomic structure of gold
3. Figure 2.3: Excerpt from the periodic table of elements
4. Figure 2.4: Good conductors
5. Figure 2.5: Allotropes of carbon
6. Figure 2.6: Electrons flowing in a conductor
7. Figure 2.7: Conduction
8. Figure 2.8: Induction
9. Figure 2.9: Simple electrical circuit
10. Figure 2.10: Soldering on a PCB
11. Figure 2.11: Expanding breadboards
12. Figure 2.12: Bottom of breadboard
13. Figure 2.13: Breadboard clip
14. Figure 2.14: Breadboard features
15. Figure 2.15: Binding post close-up
16. Figure 2.16: Power rails jumpered together
17. Figure 2.17: An IC in DIP format across a breadboard dip
18. Figure 2.18: Breadboard rows and columns
19. Figure 2.19: LEDs
20. Figure 2.20: Jumpers, wire stripper, needle-nose pliers, and safety glasses...
21. Figure 2.21: Completed LED circuit
22. Figure 2.22: LED shorted out
23. Figure 2.23: Ohm's law
24. Figure 2.24: Carbon film resistors
25. Figure 2.25: Resistor color code
26. Figure 2.26: Voltage divider
27. Figure 2.27: Fuses and a circuit breaker
28. Figure 2.28: Imprint on a fuse casing
Chapter 3
1. Figure 3.1: Block diagram and schematic
2. Figure 3.2: Conductor symbols
3. Figure 3.3: Common schematic symbols
4. Figure 3.4: Poles and throws
5. Figure 3.5: A sampling of switches
6. Figure 3.6: Schematic symbols for switches
7. Figure 3.7: Datasheet
8. Figure 3.8: What you need
9. Figure 3.9: Wiring diagram of simple circuit with switch
10. Figure 3.10: Vertical resistor
11. Figure 3.11: Completed circuit with switch
12. Figure 3.12: Schematic for simple circuit with switch
Chapter 4
1. Figure 4.1: Arduino Uno board
2. Figure 4.2: ATmega328 microcontroller
3. Figure 4.3: TX and RX lights and USB port
4. Figure 4.4: Adapter for 9V battery and a transformer
5. Figure 4.5: Power jack and USB port
6. Figure 4.6: Power connections
7. Figure 4.7: Digital and analog pins, LED 13, and GND
8. Figure 4.8: A square wave
9. Figure 4.9: An analog wave
10. Figure 4.10: Binary values across 5 volts
11. Figure 4.11: Arduino reset button
12. Figure 4.12: Default Arduino IDE screen
13. Figure 4.13: Renaming a sketch
14. Figure 4.14: Project materials
15. Figure 4.15: Selecting the port
16. Figure 4.16: A flashing LED circuit
17. Figure 4.17: Choosing the Blink sketch
18. Figure 4.18: Changed Blink sketch
19. Figure 4.19: Running Lights in action
20. Figure 4.20: A pushbutton circuit
21. Figure 4.21: Serial Monitor with data
Chapter 5
1. Figure 5.1: A typical multimeter
2. Figure 5.2: AC-to-DC power transformer
3. Figure 5.3: Testing polarity
4. Figure 5.4: Taking measurements
5. Figure 5.5: Potentiometer
6. Figure 5.6: Dimming via potentiometer
7. Figure 5.7: Simple circuit
8. Figure 5.8: Measuring the circuit
9. Figure 5.9: Measuring voltage rise
10. Figure 5.10: Voltmeter and Serial Monitor
11. Figure 5.11: Arduino ohmmeter
12. Figure 5.12: Arduino ohmmeter output
13. Figure 5.13: A shunt resistor schematic
14. Figure 5.14: Ammeter circuit
15. Figure 5.15: Ammeter output
16. Figure 5.16: Arduino continuity tester
17. Figure 5.17: Camp lamp schematic
18. Figure 5.18: A button circuit
19. Figure 5.19: Breadboard configuration, one row
20. Figure 5.20: Breadboard configuration, four rows
21. Figure 5.21: A soldering station
22. Figure 5.22: Clipping solder leads
23. Figure 5.23: Perfboards
24. Figure 5.24: A heat gun and shrink tubing
Chapter 6
1. Figure 6.1: Sample datasheet
2. Figure 6.2: The power wheel
3. Figure 6.3: Resistors
4. Figure 6.4: Power meters
5. Figure 6.5: Electric supply bill
6. Figure 6.6: An LCD front and back
7. Figure 6.7: An LCD wiring diagram
8. Figure 6.8: HelloWorld sketch
9. Figure 6.9: Multimeter and circuit
10. Figure 6.10: Wattmeter connections
11. Figure 6.11: Adding a library
12. Figure 6.12: Wattmeter on an LCD
13. Figure 6.13: A completed meter and circuit
14. Figure 6.14: Meter and circuit connections
Chapter 7
1. Figure 7.1: Series, parallel, and complex circuits
2. Figure 7.2: LED circuits
3. Figure 7.3: Incandescent lamp circuits
4. Figure 7.4: A parallel branch current
5. Figure 7.5: Kirchhoff's laws
6. Figure 7.6: Parallel resistances
7. Figure 7.7: Wire gauge
8. Figure 7.8: Batteries and holders
9. Figure 7.9: Improper battery connection
10. Figure 7.10: Sources in series and parallel
11. Figure 7.11: Aiding and opposing sources
12. Figure 7.12: LED series circuit calculation
13. Figure 7.13: Solving the complex circuit
Chapter 8
1. Figure 8.1: Simple polarity tester
2. Figure 8.2: Perfboard polarity tester
3. Figure 8.3: Diodes and the PN junction
4. Figure 8.4: An anode and a cathode
5. Figure 8.5: Various diodes
6. Figure 8.6: Common diode symbols
7. Figure 8.7: A Zener voltage regulator
8. Figure 8.8: A power diode voltage divider/regulator
9. Figure 8.9: A bridge rectifier
10. Figure 8.10: A flyback diode
11. Figure 8.11: Seven-segment LED wiring
12. Figure 8.12: A bar LED
Chapter 9
1. Figure 9.1: A transistor face
2. Figure 9.2: A transistor pinout
3. Figure 9.3: An amplifier circuit schematic
4. Figure 9.4: An amplifier circuit
5. Figure 9.5: An amplifier current flow
6. Figure 9.6: Signal and power transistors
7. Figure 9.7: The hierarchy of transistors
8. Figure 9.8: Transistor symbols
9. Figure 9.9: An N-channel MOSFET
10. Figure 9.10: A transistor and heat sink
11. Figure 9.11: A circuit schematic
12. Figure 9.12: A transistor switch circuit
Chapter 10
1. Figure 10.1: Inside a capacitor
2. Figure 10.2: Common capacitor types
3. Figure 10.3: Failed electrolytic capacitor
4. Figure 10.4: Capacitor symbols
5. Figure 10.5: Time delay circuit
6. Figure 10.6: Capacitor charged and discharging
7. Figure 10.7: Transient response
8. Figure 10.8: Astable multivibrator circuit
9. Figure 10.9: Inserting a switch
10. Figure 10.10: Capacitors in parallel
Chapter 11
1. Figure 11.1: Magnetic domains
2. Figure 11.2: Magnetic lines of flux
3. Figure 11.3: Wind farm
4. Figure 11.4: Electromagnet
5. Figure 11.5: Magnetism in Circuits
6. Figure 11.6: Homopolar motor
7. Figure 11.7: Inductor schematic symbols
8. Figure 11.8: Inductors on a motherboard
9. Figure 11.9: Doorbell circuit
10. Figure 11.10: Reed relays
11. Figure 11.11: Magnetic alarm
12. Figure 11.12: A relay
13. Figure 11.13: Relay oscillator circuit
14. Figure 11.14: Emergency lighting circuit
Chapter 12
1. Figure 12.1: Water alarm
2. Figure 12.2: Inside a buzzer
3. Figure 12.3: Speakers and microphones
4. Figure 12.4: Light-based circuit control devices
5. Figure 12.5: Light bulbs
6. Figure 12.6: Laser pointer
7. Figure 12.7: Night-light circuit
8. Figure 12.8: Electron flow in the night-light
9. Figure 12.9: Laser alarm circuit
10. Figure 12.10: Calculating analog in values
Chapter 13
1. Figure 13.1: Inside a 555 timer IC
2. Figure 13.2: Mark time, space time, and cycle
3. Figure 13.3: A 555 Astable timer circuit schematic
4. Figure 13.4: A 555 timer pinout
5. Figure 13.5: A 555 timer circuit
6. Figure 13.6: A completed astable circuit
7. Figure 13.7: Inverting and noninverting op-amp
8. Figure 13.8: Decimal, binary, and hexadecimal
9. Figure 13.9: Logic gates and truth tables
10. Figure 13.10: A logic gate pinout
11. Figure 13.11: An AND gate pinout and circuit
12. Figure 13.12: OR gate and NOT (inverter) pinouts
13. Figure 13.13: Logic pulser
14. Figure 13.14: Oscilloscope
Chapter 14
1. Figure 14.1: Duty cycles
2. Figure 14.2: Datasheet with duty cycle
3. Figure 14.3: PWM LED dimmer circuit schematic
4. Figure 14.4: PWM LED dimmer circuit pinout
5. Figure 14.5: PWM LED circuit complete
6. Figure 14.6: Complete circuit with oscilloscope
7. Figure 14.7: Flyback diode
8. Figure 14.8: Clamping Zener diodes
9. Figure 14.9: PWM motor circuit with flyback diode
10. Figure 14.10: Simple Arduino PWM circuit
Chapter 15
1. Figure 15.1: A homemade voltaic cell
2. Figure 15.2: Homemade thermocouple
3. Figure 15.3: Construction of a PV cell
4. Figure 15.4: PV cells, panels, and array
5. Figure 15.5: Project pinout
6. Figure 15.6: PV cell’s Serial Monitor output
7. Figure 15.7: Completed PV monitoring circuit
8. Figure 15.8: Inside a motor/generator
Chapter 16
1. Figure 16.1: Common transformers
2. Figure 16.2: Inside a transformer
3. Figure 16.3: Phase relationships
4. Figure 16.4: Calculating current, voltage, and turns ratios
5. Figure 16.5: Autotransformers, variacs, and taps
6. Figure 16.6: A transformer label
7. Figure 16.7: A 555 timer circuit
8. Figure 16.8: A transistor section
9. Figure 16.9: Completed transformer circuit
10. Figure 16.10: Demo circuit readings
Chapter 17
1. Figure 17.1: Typical PV system
2. Figure 17.2: A small inverter
3. Figure 17.3: An inverted signal circuit
4. Figure 17.4: Inverting current
5. Figure 17.5: An Arduino PWM circuit
6. Figure 17.6: A square wave
7. Figure 17.7: A single RC filter stage
8. Figure 17.8: Four RC filter stages
9. Figure 17.9: Filtered oscilloscope outputs
10. Figure 17.10A: Half-wave rectification
11. Figure 17.10B: Full-wave rectification, center tap transformer
12. Figure 17.10C: Full-wave rectification, bridge rectifier
13. Figure 17.11: Single-phase and three-phase power
14. Figure 17.12: Variable power supply circuit
15. Figure 17.13: A variable power supply
Chapter 18
1. Figure 18.1: The electromagnetic spectrum
2. Figure 18.2: A crystal radio and amplifier schematic
3. Figure 18.3: Amplifier circuit complete
4. Figure 18.4: A simplified radio transmitter
5. Figure 18.5: A simplified radio receiver
6. Figure 18.6: AM and FM waves
7. Figure 18.7: The TEA5767 FM radio shield
8. Figure 18.8: Installing a library
9. Figure 18.9: Finding a library
10. Figure 18.10: Displaying line numbers in the IDE
11. Figure 18.11: Radio module connections
12. Figure 18.12: Potentiometer station selection
13. Figure 18.13: Tuned circuits
Chapter 19
1. Figure 19.1: The Arduino Create main screen
2. Figure 19.2: A blue LED dimmer circuit
3. Figure 19.3: Your Things screen
4. Figure 19.4: The properties of Blue_Light
5. Figure 19.5: The Editor page
6. Figure 19.6: The thingProperties.h tab
7. Figure 19.7: The Secret tab
8. Figure 19.8: The ReadMe.adoc tab
9. Figure 19.9: The IoT Cloud thing
10. Figure 19.10: Welcome to Dashboards
11. Figure 19.11 Widgets
12. Figure 19.12: The widgets added screen
13. Figure 19.13: Linking the widget
Chapter 20
1. Figure 20.1: A sewable LED kit
2. Figure 20.2: SMD examples
3. Figure 20.3: The thread circuit
4. Figure 20.4: Separate LED boards
5. Figure 20.5: Threading the needle
6. Figure 20.6: Sewing the components
7. Figure 20.7: Project complete
8. Figure 20.8: SMT stick-on LEDs and circuits
9. Figure 20.9: Graphite conductors
10. Figure 20.10: A painted circuit
11. Figure 20.11: Paint over a painted circuit
12. Figure 20.12: A copper tape circuit
13. Figure 20.13: The copper tape card front
14. Figure 20.14: Finishing the card
15. Figure 20.15: The insulating square
16. Figure 20.16: The lit blue dough square
17. Figure 20.17: The lit flag

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ISBN: 978-1-119-68368-1
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ISBN: 978-1-119-68369-8 (ebk)

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Introduction

Welcome to the world of electronics! This is an exciting place to be, and I'm so glad that you've decided to join me in this journey. IoT and electronics are inseparable, as you'll soon see. We'll start with learning about electronic components and creating some useful circuits. In addition to traditional electronic circuits on breadboards, many chapters have circuits that use the programming power of an Arduino board. Finally we'll be connecting your circuits to the Internet so you can control them from anywhere. This book starts small and helps you grow in knowledge as it progresses and encourages you to reach even further. My true hope is that it will get you excited about working with electronics, regardless of whether it's a hobby or a new career, and that it will give you confidence to do whatever it is that makes your heart sing, no matter who or where you are in life.

I'm here to tell you that virtually everyone can do electronics, you included. Although this is a male-dominated field, I encourage you not to let that deter you from getting into the game. If you're female or any other non-traditional geek, follow your passion like I did. Like me, you may be the only woman in the room, but that's perfectly fine. It's an exciting and dynamic career field, and if you're different from the stereotypical electronics geek in some way, that's great! You bring a different perspective, which makes you that much more valuable.

Who Will Benefit Most from This Book

This book is intended for beginners, or those with some basic electronics knowledge who want to fill in those knowledge gaps with tidbits of information that can make all the difference. You'll start with the basics and progress to more interesting (difficult) projects as you go along. This book contains more than 35 “Try This” projects where you can see how things work and solidify what you're learning. Some of the projects include the following:

Creating a super-bright camping light using LEDs
Building a laser trip alarm
Making paper and clay electronics for kids
Creating light-activated circuits
Constructing an Arduino wattmeter
Connecting your projects to the Internet

You'll learn some science behind how things work so the components and connections will make sense, and you'll learn how to avoid some of the pitfalls of circuit building. For example, after studying the material in this book, you'll know why you need a flyback diode for a motor (and understand what one is), instead of having to figure it out when the circuit fails and you're on your third set of components. However, I expect there may be some of that in your future, too, as you take your own ideas and build them into new and interesting circuits. Mistakes are part of the learning process. That's the fun of experimenting! You will create prototype circuits on breadboards, and if you're happy with the result, you can solder them onto something more permanent because you'll know how to do that, too.

Sourcing Parts and Supplemental Materials

I wouldn't want to teach you to fly and then leave you on your own, so throughout the book I've included some of my favorite places to find information and components.

My website, cliffjumpertek.com, also has additional reference materials, tutorials, and videos of the book's projects to help with your journey, should you need it.

Special Features

Time to turn the page and get started on your future in electronics! I'll see you there.

What Does This Book Cover?

This book is designed to provide you with a foundation of knowledge in electronics, IoT, and the Arduino environment. Its multitude of projects are the springboard to a deeper understanding and ever more challenging projects.

Chapter 1: IoT and ElectronicsThe book starts with an explanation of how electronic circuit boards fit into the world of IoT. The components of an IoT system are explained, showing how IoT starts with electronic sensors and then interfaces with computers and communication systems. It also notes some of the challenges in developing and using IoT systems, as well as where IoT may be headed in the future.
Chapter 2: Electricity: Its Good and Bad Behavior Understanding how electricity behaves will help you to determine why circuits are or are not working. This chapter delves into the science behind electricity. It also explains electricity's characteristics and the relationship between those electrical characteristics. You'll learn how to build a simple circuit and then how to create a circuit on a breadboard, which is the foundation for most of the circuits created in the rest of the book.
Chapter 3: Symbols and Diagrams The field of electronics uses symbols to represent components when communicating information. This chapter teaches the basic symbology used and how to create a breadboard circuit using a schematic as a guide.
Chapter 4: Introduction to the Arduino Uno The Arduino is a popular platform for creating IoT implementations. In this chapter, you'll learn the form and function of the Arduino Uno and its programming platform. You'll also learn about analog and digital signals and the role of binary, all while building projects.
Chapter 5: Dim the Lights This chapter gets its name from one of the eight labs included in it; however, it's more about measuring electricity. You'll learn to use a multimeter and create a voltmeter, ohmmeter, and ammeter using an Arduino board. There's also a great project for creating a camp lamp, and it finishes with a lesson on soldering, perfboards, and shrink tubing, so you'll know how to put those projects together on a more permanent basis.
Chapter 6: Feel the Power Power is another characteristic of an electrical circuit and is explained in this chapter. You'll learn the relationship between Ohm's law and Watt's law as well as power from batteries, power ratings of resistors, and ways to measure circuit power. You'll also learn how to use an LCD screen with an Arduino board.
Chapter 7: Series and Parallel Circuits Electricity behaves differently depending on the path that it takes through a circuit. This chapter explains the implications of letting it take those different paths. You'll also learn about the effect of wire size and composition. In the spirit of full disclosure, this chapter involves math.
Chapter 8: Diodes: The One-Way Street Sign This is the first of several chapters about specific electronic components. You'll learn about diode construction and why diodes behave as they do, along with some common uses for diodes. The projects show you how to work with seven-segment LEDs and bar LEDs.
Chapter 9: Transistors You may know that transistors are the foundation of our modern computer processors, but they can do so much more. This chapter explains different types of transistors and their uses while giving you some practice working with them.
Chapter 10: Capacitors Another powerhouse when it comes to computer circuits is the lowly capacitor. They're found everywhere and sometimes taken for granted. This chapter teaches you the characteristics of capacitors and gives you some experience putting them to work.
Chapter 11: The Magic of Magnetism Magnetism and electricity are like two sides of a coin. This chapter examines that relationship and how magnetism is put to serious work. You'll also learn about relays, which are a component of many industrial electronic circuits.
Chapter 12: Electricity's Changing Forms Working with electricity is even more fun when you can change it into light and heat and sound, or vice versa. This chapter shows you several ways to do just that, along with the science behind the changes.
Chapter 13: Integrated Circuits and Digital Logic Integrated circuits make our work easier by having an entire circuit on a chip the size of your thumbnail, or even smaller, while digital logic chips can be the decision-makers on our circuits. This chapter explores both and introduces the oscilloscope, which lets you see in real time what is happening electrically in a circuit.
Chapter 14: Pulse Width Modulation Pulse width modulation (PWM) enables a digital signal to control an analog device, such as a motor. In this chapter, you'll build a PWM circuit on a breadboard and then learn how to accomplish the same magic using an Arduino board.
Chapter 15: Sources of Electricity Sources of electricity are touched upon in other chapters, but this one brings all the pieces together in one place. Here you can practice making some electrical current of your own and build an Arduino circuit to monitor the output of a photovoltaic cell.
Chapter 16: Transformers and Power Distribution Transformers are used to change the electrical properties of a circuit and play a big role in power supplies and power distribution. This chapter examines the types and roles of transformers. It also explains how they accomplish changing electrical properties and gives you some experience working with one.
Chapter 17: Inverters and Rectifiers Many times a circuit needs to be converted from DC to AC or AC to DC. The devices that perform that task are called inverters and rectifiers, respectively. In this chapter, you'll learn how both work and how to filter circuits for a more desirable and consistent output. You'll even build a small variable power supply.
Chapter 18: Radio Waves and Tuned Circuits Radio waves are the communication vehicles of our cell phone networks, local area networks, and free music stations. Their use grows every day, so knowing how they work is important whether you're working with computers or IoT devices. This chapter explains AM and FM and introduces working with an Arduino shield to create a radio.
Chapter 19: Connecting Your Circuits to the Cloud Being able to control devices remotely is an important aspect of many IoT implementations. This chapter teaches you how to do just that using a Wi-Fi enabled Arduino board and the Arduino IoT cloud.
Chapter 20: Just for Fun While working with electronics is always fun, most of the time electronic circuits are created for serious work. This chapter explores some of the not-so-serious uses of electricity. If you're the least bit creative, and I'm sure you are, then this chapter is for you!

CHAPTER 1
IoT and Electronics

“Toto, I have a feeling we're not in Kansas anymore.”

—Dorothy, The Wizard of Oz

Sci-fi movies and shows have always been my obsession. As a child, I would watch in awe when reruns of The Jetsons showed people talking on video phones, the almost-human robot maid, and sidewalks that moved. Then there were the Star Trek reruns where characters walked around with communicators that allowed them to talk to anyone just by tapping them. Later, Star Wars had language translators that would automatically translate into any other language … rather like what Google Translator does now.

Forty or fifty years ago, many devices and capabilities that are commonplace now were considered ridiculous, impossible, or mere fantasy. Were these movies and TV shows predictions of the future, or did they help to shape the future by putting these notions of “impossible” devices into someone's mind to start working on? Either way, many of those devices exist now for us in some form or another. Even 20 years ago, most people still depended on their home phones for communication. Do you know anyone who still has a landline at home? They are few and far between.

The Electronics Technicians Association was founded in 1978 as the electronics industry was beginning to grow slowly. Now, it's growing by leaps and bounds on a daily basis. It's astonishing how far electronics have come in such a relatively short time when compared to human existence, and it's even more incredible when we ponder how far we will be 50 years from now. Many of the technological advances of the future will be here due to artificial intelligence, machine learning, and the myriad of sensors starting to cover our world. The world is about to take another leap forward, and if you want to be part of that journey, learning electronics is the place to start. As so many maps show us … “You Are Here.”

IoT in a Nutshell

What is IoT? As you may know, IoT stands for “Internet of Things.” IoT refers to a vast array of connected devices that gather and transmit data over interconnected networks with or without human intervention, sometimes even responding to the captured data automatically as machines talk to machines and learn from each other. (When IoT involves manufacturing processes, it is often called industrial IoT [IIoT].) IoT can include data gathered by proximity sensors on your car's front that detect deer in the roadway and signal your brakes to immediately slow down the car without you doing anything. It also includes when moisture levels (or lack thereof) are transmitted from a field to that field's watering system, signaling to turn on the irrigation system without a human lifting a finger. Even a dog's GPS-enabled location device is part of an IoT system, as is the Tile that I press to locate my often-misplaced car keys.

Other systems considered part of IoT are smart cities, smart grids, smart homes, smart watches, and manufacturing machines talking to and learning from each other. Smart devices are used in hospitals, schools, retail, and nearly any other service or business you can think of. Last year, I attended a virtual meeting with someone from a major networking device company. He was speaking from his office about power over Ethernet and how the interconnected devices controlling heat, lighting, air quality, etc., all ran automatically in the high-rise office building he was in. I noticed a model of a pig on the credenza behind him and asked about it. Yes, it was a pig wearing an IoT collar.

What does this have to do with learning electronics? Everything! Electronic sensors and circuits are the beating heart of an IoT system.

Parts of an IoT System

What comprises an IoT system changes depending on who you ask, but regardless of what particular twist an industry or company may put on it, certain things must be there. For an overview of an IoT system, see Figure 1.1.

Devices

What is an IoT device? IoT devices include sensors, circuits, software, actuators (things that do something, such as switch from one state to another), and microprocessors, all rolled into a neat little package. These devices also need a way to communicate and send data to a place where it will be processed, manipulated, and action taken based on the data, or they need to be able to communicate to receive instructions based on the data that was gathered by some other device. Therefore, an IoT device can be on either the sending end or the receiving end, or possibly both.

Schematic illustration of an IoT system. — **Figure 1.1**: An IoT system

Take, for example, a smart home with a remote-controlled thermostat, which has a few layers of things going on. First, the thermostat is a device. It has a sensor that measures the temperature and sends that information to a circuit board with a microprocessor where the reading is converted into data, which is manipulated. If certain conditions within the software program are met, the microprocessor sends a command to another component, telling it to turn the furnace either off or on. This example is machine to machine but involves sensors, circuits, software, microprocessors, communication, and actuators.

Another function of this device would be the ability to access the device from a cell phone via the Internet and Wi-Fi to tell the device to turn up the heat before the user gets home. This example involves a user interface, which is part of the entire user experience, but here we have the cell phone acting as a device and the thermostat acting as another device, communicating via the Internet.

Sensors

The first part of any IoT system is a device that senses something physical, whether a particular condition or event. It could be a fiber optic cable in a building's concrete that picks up a pressure change, or it could be a proximity sensor, heat sensor, humidity sensor, optical sensor (ambient light, IR, UV), gas sensor, position sensor, magnetic sensor, motion sensor (accelerometer, gyroscope), color sensor (light again), or touch sensor (pressure). A search for sensors on an electronics components site at the time of this writing yielded tens of thousands of results.

As mentioned in the preceding section, a sensor receives some form of raw data and passes it on to a circuit and most likely a microprocessor, where the data received is interpreted. Take, for example, a temperature. The sensor doesn't send “temperature” to the circuit. Instead, a change in the temperature causes a rise or fall in either current or voltage through the device, which is passed to a circuit where it is read and interpreted according to instructions, known as software, controlling what the microprocessor tells the circuit to do. In future chapters, you'll learn how to work with some of these sensors and what the technology is that drives them.

Choosing the right sensor is an important first step, and several characteristics need to be considered.

What's being measured: Temperature, light, pressure, etc.
Electrical: Current, voltage, and power limitations.
Physical: How much pressure, heat, light, etc., can it endure and remain viable?
Accuracy: How far might it vary from the actual measurement?
Sensitivity: How much does the input need to change before the output changes?
Reliability: What is the track record of this sensor? When does it stop being accurate? How often does it break down?
Range: What are the minimum and maximum values that can be measured?

Circuits, Software, and Microprocessors

Once the right sensor is found, the circuitry and software can be designed to interpret the information that is provided by the sensor. A myriad of choices exists for all of these. A microprocessor can be a single chip designed to perform logic or a microprocessor platform, such as an Arduino device. The choice of processor may determine the choice of software that is used.

Communication

Because the “I” in IoT stands for Internet, the assumption can be made that the device is expected to be interconnected in some way either through a local area network (LAN) or through the Internet. However, different levels and aspects of communication may be used by IoT devices.

Levels

A device may communicate with other devices, such as a moisture sensor in a field that triggers a watering system to work, or devices in a factory assembly line that communicate with other devices to either slow down or speed up the processes based on conditions. This is machine-to-machine communication. Systems like these may even use machine learning, which is a process where computers use algorithms to look for related data and learn, changing their programming based on data without human intervention. Machine learning is far too complicated to explain here but definitely an emerging technology worth paying attention to.

In the automatic watering system example, the devices may be connected only to a LAN, but most likely they will be gathering data and sending it, via one or more protocols and networks, to a place where it is processed.

Protocols and Standards

Protocols are essentially rules for communication, and they are the topic of much learning and discussion in the computer world. Standards typically define how a network is built and what protocols are used on it. Networking standards are needed to ensure that different devices, possibly from different vendors or manufacturers, are all able to communicate effectively. Knowing what type of communication is needed and used by each part of an IoT system is an important consideration. Any of the following standards might be part of an IoT system:

Ethernet: Wired LAN networking standard
Bluetooth: Short-range wireless, usually connecting mobile devices
Wi-Fi: Wireless networking standard allowing wireless networks to connect to a wired system or each other
Cellular: For longer-range wireless connectivity via the cellular system

Each of these standards may have multiple protocols that are used with that particular standard, and any of them may allow a device to connect to the Internet. Often more than one will be used. In the case of the smart thermostat, it may use Wi-Fi to connect to a local LAN using Ethernet, which is connected to the Internet via some other method, such as a cable modem, fiber optics, or satellite. The remote user may be connecting their cell phone to the thermostat via Wi-Fi or the cellular network. All of these standards need to work in harmony for successful communications across an IoT system.

Data Analytics and Management

Data analytics is the growing field of sorting and analyzing raw data to derive meaningful and actionable information from it. It is the stuff of algorithms and perhaps insight gained from the experience of working with data. Four basic types of data analysis exist.

Descriptive
Diagnostic
Predictive
Prescriptive

Descriptive analytics identifies what has happened based on data. It is often based on key performance indicators (KPIs). For example, did sales go up or down and by how much or what percentage? Did the field have to be watered more often or less often?

Diagnostic analytics attempts to explain why the changes occurred. It can look at data outliers and what was occurring when the change in data occurred.

Once the what and why are known, predictive data analysis models can be built to anticipate problems before they happen or identify future trends.

Finally, prescriptive data analysis gives the user a course of action to take to avoid the problems identified in predictive models or to take full advantage of what's around the corner.

Data is more valuable than the hardware and software used to mine it from various sources, so managing that data is a primary concern for any business. The field of data management is concerned with collecting data, maintaining its physical security, securing the privacy of any personally identifiable information (PII), and preserving that data in a cost-effective and efficient manner. Data analytics is part of data management, and the way this data is used can cause a business to flourish or fail.

The User Experience

The user experience refers to every place that the user and the IoT system come into contact with each other. If, for example, an employee is tasked with identifying a problem quickly and accurately, then the interface that the employee uses needs to have the right information in an application that is easy to use, and it needs to be updated in a timely manner.

Depending on the situation or business, the user experience can also include interacting with customer service or other personnel, how easy the phone system is to use, etc.

Challenges in Implementing IoT

Implementing technology is not without challenges, particularly in an IoT system. One of the biggest challenges for remote IoT devices is power. Running electrical wires is not always practical, and batteries have a limit to their capacity, so creating a system that runs on as little power as possible, or perhaps renewables like solar power, is a significant hurdle to overcome in developing an IoT solution.

Another major concern is the security and ownership of data. If data is stored by a provider, who owns and has access to the data? What encryption will be used to transmit the data from where it's gathered to where it's used? These are questions that any businessperson would want to know before implementing a system. Determining the right data to gather is probably the first question to answer, because measuring the wrong facts won't help a business make the right decisions.

Perhaps the biggest challenge of all is cohesiveness. If a system is cohesive, then it works together smoothly, which can be a problem when so many different systems are involved. Beginning with the sensors that detect data, through the circuitry and networks that transfer and store the data, then send the data to a user's interface on a device such as a phone or computer, and back again as the user responds through a local network to the web and then to the actuator; during this process, there needs to be a seamless way to transmit and manipulate the data. With so many protocols and systems involved, that can be difficult indeed. Developing a system needs to start with a bird's-eye view of the major parts, working down to the component level to ensure that all of the system's parts work together to move data around smoothly.

IoT into the Future

IoT and IIoT will not be going away in the foreseeable future. In fact, they will continue to grow as processes and machines get smarter and people find more uses for IoT. What may have started as a curiosity, with devices that were more fun than function in the hands of a few hackers, is now a major industry and will be causing paradigm shifts in virtually all industries and businesses.

Devices and sensors will continue to get smaller, get less expensive, and work better. We will learn how to better harvest the data from IoT devices and put them to more and more uses. Already billions of IoT devices are being used, and the number increases exponentially as every day forward-thinking inventors and electronics enthusiasts devise more uses for the technology. Where will you fit into this growing industry? Perhaps the best place to start is with a basic understanding of electronics, and to that end, read on.

A Geek Girl’s Guide to Electronics and the Internet of Things

About the Author

About the Technical Editor

Acknowledgments