LESSONS Lesson 1. Microcontrollers and SBCs. The Big Idea: Lesson 1: Microcontrollers and SBCs. Background: What, precisely, is computer science?

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1 LESSONS Lesson Lesson : Microcontrollers and SBCs Microcontrollers and SBCs The Big Idea: This book is about computer science. It is not about the Arduino, the C programming language, electronic components, or the mathematics 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 experiment 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 -. Table -. 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 Microcontrollers and SBCs

2 The key word is model. Consider Table -2, examples of the uses of models in computing. Table -2. Examples of models in computing Example What is modeled How model connects to world League of Legends Digital medical imaging via Magnetic Resonance Microsoft Word Aircraft Autopilot A fantasy world where characters possess magical and physical powers. The detailed densities of the portions of the body being scanned. The appearance of formatted text as if it were typed directly onto a piece of paper. The stable flight of an aircraft. 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. By collecting data about minute movement of molecules in response to a changing magnetic field, a model of the scanned object is created. This model is presented to the user as startlingly detailed 2D and 3D images of what would be found if the subject were opened surgically. 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. The computer collects data (speed, direction, physical orientation of the aircraft, altitude) 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 something 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 models 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. 2 Learn to Program in Arduino TM C: 8 Lessons, from setup() to robots

3 Table -3. Vocabulary Term Definition algorithm A means of or steps to performing a specific task. For a computer, an algorithm is usually expressed in a set of computer program instructions. 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 sketches 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 create 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 performs the processing tasks of a computer, including input, output, and computation. output Information of any sort that comes out of a computer. single-board computer (SBC) An entire microcomputer on a single printed circuit 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. Lesson Microcontrollers and SBCs 3

4 Figure -. 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 members 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 language 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. 4 Learn to Program in ArduinoTM C: 8 Lessons, from setup() to robots

5 Goals: By the end of this lesson you will:. 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: Quantity Arduino Uno USB Cable Part Image Notes Computer with at least one USB port and access to the Arduino website, cc. --- 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. This is the standard USB adapter cable with the flat connector on one end and the square connector on the other. The operating system of this computer must be Windows, Macintosh OS/X, or Linux. Catalog Number 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: Lesson Microcontrollers and SBCs 5

6 Part I: Download, install, and test the Integrated Development Environment. Open Internet Explorer or another Internet browser and navigate to the Arduino website 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. 6 Learn to Program in Arduino TM C: 8 Lessons, from setup() to robots

7 4. The IDE work space should then appear. Part II: Connect and test the Arduino Uno. 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]. Lesson Microcontrollers and SBCs 7

8 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 established, 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. 8 Learn to Program in Arduino TM C: 8 Lessons, from setup() to robots

9 Exercises: Exercise -. Verify success of Blink sketch. 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]. Lesson Microcontrollers and SBCs 9

10 3. Modify the MyBlink sketch to make the light blink on and off at half-second intervals by changing the number 000 to 500 in the two delay statements. Don't be concerned about understanding 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 -2. Verify sketch runs on Arduino and experiment with time delays. Verify that the modified sketch is, in fact, running on the Arduino and not on the computer to which the Arduino is connected. 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 (30 in Parts Catalog) or a battery pack. Note: The light should blink even though the Arduino is now independent of the computer. 2. The number used in the delay statement, delay(500);, is a measure of time in milliseconds. 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. 0 Learn to Program in Arduino TM C: 8 Lessons, from setup() to robots

11 3. Experiment with at least six values of delay for time on. Set the delay for the light off to be one second. That is 000 milliseconds. Complete Exercise Table -. Exercise Table -. Time delay experiment table Condition Time On, in Milliseconds Light on longer than necessary: Light not on long enough to be noticed reliably: Optimal time on: Lesson Microcontrollers and SBCs

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