Getting Started with Adafruit Trinket: 15 Projects with the Low-Cost AVR ATtiny85 Board

by Anne Barela

Overview

Arduino's ubiquity and simplicity has led to a gigantic surge in the use of microcontrollers to build programmable electronics project. Despite the low cost of Arduino, you're still committing about $30 worth of hardware every time you build a project that has an Arduino inside. This is where Adafruit's Trinket comes in. Arduino-compatible, one-third the price, and low-power, the Trinket lets you make inexpensive and powerful programmable electronic projects. Written by one of the authors of Adafruit's Trinket documentation, Getting Started with Trinket gets you up and running quickly with this board, and gives you some great projects to inspire your own creations.

Product Details

ISBN-13:	9781457185946
Publisher:	Make Community, LLC
Publication date:	10/23/2014
Pages:	257
Product dimensions:	5.40(w) x 8.40(h) x 0.70(d)

About the Author

Engineer, Maker, and innovator Mike Barela is a Senior Foreign Service Officer with the US Department of State. A graduate of both Whitman College and the California Institute of Technology in Electrical Engineering, he has worked at Hewlett-Packard, the NASA Jet Propulsion Laboratory, and Boeing. He has traveled the world, living in a number of countries providing security to American Embassies. An avid electronics enthusiast, he has worked on computers since the introduction of the PC. He rekindled his electronics and microcontroller interests, authoring a number of popular articles on using Arduino-compatible systems. This includes collaboration with Adafruit Industries on their popular Trinket microcontroller.

Table of Contents

Foreword ix

Preface xi

1 Introducing Trinket 1

Trinket Versus Arduino Uno 2

Using Trinket 3

The ATtiny85 Microcontroller 3

Memory 4

Connectivity 5

Three Volts or Five Volts? 7

The Adafruit Gemma 8

2 Software Installation 9

Supported Operating Systems 10

The Preconfigured Arduino IDE from Adafruit 10

Modifying the Standard Arduino IDE 11

The USBtinyISP Driver for Windows 11

Seeing the Trinket in Windows 14

Windows Driver Troubleshooting 15

Linux 15

Conclusion 15

3 Connection and Programming 17

Preparing the Trinket 17

Connecting Trinket to Your Computer 19

Loading a Program 21

The Trinket Data Pins 24

Digital Pins 24

Analog Pins 25

Exploring Data Pins 25

Parts List 25

Connections 26

Not All Pins Are the Same 26

Different Ways to Power Trinket 28

Analog and Digital Sensors 30

Trinket Theremin 30

Parts List 30

Wiring 32

Code 32

Use 34

Sound and Music 34

Conclusion 35

4 Libraries and Optimization 37

Arduino Libraries 37

ATtiny-Optimized Libraries 39

Installing Libraries 41

Where to Install Libraries 42

Installing a Library in Windows 44

Installing a Library in OS X 47

Using Libraries 49

Library Issues and Limitations 50

Memory Optimizations 50

Program Space Optimization 51

Variable Optimization 51

Conclusion 53

5 Intermediate Projects 55

Controlling Smart LEDs: NeoPixels 55

Important Things to Know About NeoPixels 56

NeoPixel Packaging 57

NeoPixel Ornaments 57

Parts List 58

Build 58

LED Color Organ 61

How It Works 62

Parts List 62

Build 63

Adjustments 67

Mounting 67

Kaleidoscope Goggles 68

Parts List 69

Tools 69

Battery Selection 70

Wiring 70

Software 73

Final Assembly and Use 75

Safety and Common Sense 77

Servos 78

Inside a Servo 79

Trinket Servo Control 60

Parts List 81

Wiring 81

Code 82

Use 83

Going Further 83

Using I²C-The Two-Wire Interface 84

I²C Software 85

Using I²C Displays 85

Temperature and Humidity Sensing 86

Parts List 87

Libraries 88

The LCD Display 88

Testing the Display 90

Adjustment 91

Sensing 91

Code 93

How It Works 94

Troubleshooting 95

Going Further 95

Ultrasonic Rangefinding 96

Parts List 97

Build 97

Libraries 99

Code 99

How It Works 102

Troubleshooting 102

Communicating via Serial 102

Talking Serial 104

Exploring Serial Use 104

Parts List 104

Code 105

Use 106

Going Further 108

Pulse Width Modulation 108

The Analog Meter Clock 110

Circuit Design 111

Parts List 111

Build 112

Meters 112

Libraries 13

Code 113

How It Works 115

Preparing Your Meters 116

Meter Mounting 117

Conclusion 119

6 Advanced Projects 121

Trinket Jewelry 121

Parts List 122

Choices 122

Tools 123

Wiring 123

Libraries 124

Code 125

Animation 128

Compile 131

Changing the Animation 132

Finishing the Jewelry 133

Program Memory for Data 134

Trinket Occupancy Display 135

Parts List 136

Tools 137

Wiring 137

Libraries 139

Code 139

Enclosure and Board 141

Box Connections 142

Adjustment 143

Room Placement 145

Going Further 145

Trinket Alarm System 146

Parts List 147

Tools 147

Theory 148

Multiple Sensors, One Pin 149

Project Design 151

Annunciation Selections 152

Build 153

Populating the Board 154

Code 157

Final Assembly 160

Test 161

Troubleshooting 163

Going Further 163

Bluetooth Communication 164

Trinket Toy Animal 165

Choosing Your Animal 165

Parts List 186

Tools 167

Circuit 167

Circuit Variations 168

Code 169

Preparing the Toy 171

Use 173

Trinket Rover Robot 173

Parts List 176

Tools 175

3D Printing 176

Build 176

Wiring 179

Code 181

Going Further 183

SPI Communications 183

Trinket Audio Player 185

Parts List 186

Tools 187

Software 188

Loading Sounds 188

Chip Loading Circuit 139

Transferring Audio 192

Sound Playback 193

Use 197

Conclusion 197

7 Going Further with Trinket 199

Microcontrollers: Smaller Versus Larger 199

The Trinket Bootloader 200

The Bootloader Design 201

Bootloader Code 201

Repairing the Trinket Bootloader 202

Programming Bare ATtiny85 Chips 203

Other AVR Programming Methods 205

Community Resources 206

Learning Arduino 207

Commercial Resources 207

Technical Resources 208

Third-Party Sites 208

Social Media Resources 209

8 Troubleshooting 211

Your USB Cable 211

Connectivity Issues 212

Arduino IDE Issues 215

Mac 215

Common Library Problems 217

Error Messages 219

Compilation Issues 219

Upload Errors 221

The Serial Monitor 222

Usage Issues 222

Manufacturer Support 224

A Making Electronic Sounds 225

B Parts Sourcing 231

C Publications 235

Index 237