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Lesson 1 Microcontrollers and SBCs | 1

1LESSONSLesson 1

The Big Idea:This book is about computer science.

It is not about the Arduino,™ the C programming language, electronic components, or the mathe-matics of electricity—even though we refer to them extensively in the lessons in this book.

The Arduino,™ the C programming language, electronic components, and the mathematics of electricity are the tools this book uses to teach computer science.

These tools allow readers to learn by doing, to learn with their hands. Every lesson is either an ex-periment or a project. Some projects, lighting LEDs, for example, are simple. Others are complex. Laser tag is an excellent example. But simple or complex, none of the projects does anything unless some computer science has been applied to bring them to life.

Background: What, precisely, is computer science? For the purposes of this text, computer science is the application of numbers and logic to make devices, algorithms, and languages that, together, can model just about anything. This book uses the tools listed in Table 1-1.

Table 1-1. Tools this book uses Tool Description

devices The Arduino™ family of Single-Board Computers (SBCs).algorithms The collection of programming techniques, tools, and libraries we use to

build our models.language The C programming language.

Lesson 1: Microcontrollers and SBCs Microcontrollers and SBCs

2 | Learn to Program in ArduinoTM C: 18 Lessons, from setup() to robots

The key word is model. Consider Table 1-2, examples of the uses of models in computing.

Table 1-2. Examples of models in computingExample What is modeled How model connects to world

League of Legends

A fantasy world where characters possess mag-ical and physical powers.

Players (humans) participate by controlling the actions of some of the characters. High quality graphics and game play allow the user to suspend disbelief and pretend the world is real and that the player is actually the character being controlled.

Digital medical imaging via Mag-netic Resonance

The detailed densities of the portions of the body being scanned.

By collecting data about minute movement of molecules in response to a changing magnetic field, a model of the scanned ob-ject is created. This model is presented to the user as startlingly detailed 2D and 3D images of what would be found if the sub-ject were opened surgically.

Microsoft Word The appearance of for-matted text as if it were typed directly onto a piece of paper.

The user can add to and modify both the content and appearance of this text and can cause a copy of the model to be printed on paper.

Aircraft Autopilot The stable flight of an air-craft.

The computer collects data (speed, direc-tion, physical orientation of the aircraft, al-titude) and uses the model to control wing surfaces and engine speed.

Notice that in each case the computer creates and maintains a model. That model might be some-thing that exists in reality or something entirely fictional. And the output from the model may be information that appears on a screen, instructions that control physical devices, or a physical product, such as text or graphics printed on paper or plastic.

The important takeaway is this: all computer programs are models.

The lessons in this book contain experiments and projects that explore concepts and build mod-els that control lights, make sounds, run robots, turn motors, detect and compose messages, and more. Some of these models will collect and respond to data from their environments. Some will provide text as their output, and others will control physical devices. But every experiment and project is controlled by an Arduino™ running a model of what is being built. And, that model will be written with the C programming language.


1Table 1-3. VocabularyTerm Definition

algorithm A means of or steps to performing a specific task. For a computer, an algorithm is usually ex-pressed in a set of computer program instruc-tions.

Arduino™ A single-board computer and an open-source electronics platform based on easy-to-use hardware and software. It's intended for anyone making interactive projects.

C programming language The programming language used to write sketch-es for the Arduino™ SBC. The syntax is similar to several other commonly used programming languages, including C++, C#, and Java.

Integrated Development Environment (IDE)

A collection of computer programs used to cre-ate other computer programs.

microcontroller A complete self-contained computer in a chip, including the memory for a program and its data. This small microprocessor also contains the necessary electronics to communicate with external devices.

microprocessor A complex electronic integrated circuit that per-forms the processing tasks of a computer, in-cluding input, output, and computation.

output Information of any sort that comes out of a com-puter.

single-board computer (SBC) An entire microcomputer on a single printed cir-cuit board. Abbreviated SBC. Examples include the Arduino™ and the Raspberry Pi.

sketch A computer program written for the Arduino™.

Description:Arduino™ is a name given to a family of single-board computers (SBCs). The particular family member used in lessons in this book is the Arduino™ Uno. All Arduinos™ contain an integrated circuit called a microcontroller. A microcontroller is a small but complete microprocessor capable of input, output, and computation. In addition, a microcontroller includes storage memory for a computer program and its data.


Figure 1-1. The Arduino™ Uno

Surrounding this microcontroller are the electronic components, connectors, and rows of sockets necessary to bring power to the microcontroller, allow it to receive information from the outside world, and to transmit information.

The term single-board means that the entire computer fits on a single circuit board. Different mem-bers of the Arduino™ family have different features. Some are small and light enough to be sewn into clothing, while others are sufficiently powerful to perform complex tasks very quickly. But they are a family in that they are all programmed with the same language. The syntax of this lan-guage is so very close to C that it is referred to as the C language. Mastery of this language serves as an excellent base for other commonly used programming languages, including C++, C#, and Java.

The upcoming lessons explore most of the features of the Arduino™ Uno. This first lesson begins with installation and testing of the set of computer programs used to write and install Arduino™ sketches. This collection of computer programs is called the Arduino™ Integrated Development Environment (IDE). A program written for the Arduino™ is called a sketch.


1Goals:By the end of this lesson you will:

1. Know the purpose of an Integrated Development Environment (IDE).

2. Know how to locate, download, and install the Arduino™ IDE.

3. Be able to modify, save, upload, and run simple sketches for the Arduino™.

4. Know that sketch refers to a computer program written for the Arduino™.

Materials:

Quan-tity Part Image Notes Catalog

Number

1 Arduino™ Uno

Single-board computer. This board is delicate and should be handled with care. When you are not using it, keep it in a box or plastic bag.

3102

1 USB Cable

This is the standard USB adapter cable with the flat connector on one end and the square connector on the other.

2301

1

Computer with at least one USB port and ac-cess to the Arduino™ website, http://www.Arduino.cc.

---The operating system of this computer must be Windows, Macintosh OS/X, or Linux.

---

Procedure:

Important

These instructions are for Windows and will work in most situations. For Macintosh and Linux, refer to the instructions on the Arduino™ website: http://www.Arduino.cc


Part I: Download, install, and test the Integrated Development Environment

1. Open Internet Explorer or anoth-er Internet browser and navigate to the Arduino™ website http://www.Arduino.cc.

2. Locate the "Download" section of the page and select [Windows]. This will begin the download of the package that will install the IDE.

3. Double-click the Arduino™ icon.

A warning message may appear. If it does, click the [Run] button.


14. The IDE work space should then appear.

Part II: Connect and test the Arduino™ Uno

1. Connect the Arduino™ Uno to the computer using the USB cable. A small green light should appear on the Arduino,™ indicating it has power.

A small message may appear in the lower-right tray of Windows indicating to which COM port the Arduino™ is assigned. If it does, remember it because it may be needed later.

2. Click the [Tools] menu at the top of the IDE. From the dropdown menu select [Board], and from that menu select [Arduino™ Uno].


3. Select [File]. From the dropdown menu, select [Examples], then [Basics], then [Blink]. An Arduino™ program, called a sketch, will appear in the IDE. Notice that the name of the sketch, Blink, is in the tab.

4. Verify the IDE is communicating with the Arduino™ by clicking the [Upload] button on the IDE toolbar.

If communication is successfully estab-lished, the message "Uploading to I/O board" will appear at the bottom of the IDE. It will be followed by the message "Done uploading." A small light should now be blinking: on for one second, then off for one second.


1Exercises:Exercise 1-1. Verify success of Blink sketch1. Under the File menu is a submenu

called Preferences. Open [Preferences] to verify that the Sketchbook location is the Arduino™ folder in Documents.

Then click [OK] at the bottom of the screen.

2. Save the Blink sketch as MyBlink by selecting the [File] menu, then [Save as], then naming the file [MyBlink]. Click the [Save] button.

Notice that the tab in the IDE should now say [MyBlink].


3. Modify the MyBlink sketch to make the light blink on and off at half-sec-ond intervals by changing the number 1000 to 500 in the two delay state-ments. Don't be concerned about un-derstanding the sketch at this time. The intent of this step is simply to verify the proper operation of the Arduino™ Uno and the IDE.

4. Save the modified sketch by selecting [File] then [Save].

5. Upload the sketch to the Arduino™. If you're successful, the light should blink twice as fast as before.

Exercise 1-2. Verify sketch runs on Arduino™ and experiment with time delays

1. Verify that the modified sketch is, in fact, running on the Ardui-no™ and not on the computer to which the Arduino™ is connect-ed. This can be done by unplugging the Arduino™ from its USB cable and providing power to the Arduino™ by means of a wall-plug power supply (3101 in Parts Catalog) or a battery pack. Note: The light should blink even though the Arduino™ is now independent of the comput-er.

2. The number used in the delay statement, delay(500);, is a measure of time in millisec-onds. The number "500" is 500 milliseconds, or one half second. This is a common technique used to save power. For example, roadside flashers turn their lights on for short periods of time while leaving them off for a longer period. Experiment with the values of MyBlink to find the shortest blink time that still appears to be long enough to be noticed by a casual observer.


13. Experiment with at least six values of delay for time on.

Set the delay for the light off to be one second. That is 1000 milliseconds. Complete Exer-cise Table 1-1.

Exercise Table 1-1. Time delay experiment tableCondition Time On, in Milliseconds

Light on longer than necessary:___________

Light not on long enough to be noticed reliably:___________

Optimal time on: ___________
