Intro to Arduino Programming.pdf

Introduction to Arduino and
C Programming
Presentation by:
Shamim Ahmed
1

Assumptions and Goals
Assumptions
● You have taken at least one programming course prior
Goal
● Be able to create applications on arduino using the following methods
○ Adding Shields (Accessories; Attachments)
○ Adding Libraries
○ Using control flows (If-Else, Do While, While loop)
○ Using functions (Methods: e.g. getVariable, setVariable, changeVariables)
○ Reading connection diagrams
○ Debugging applications
Why
● 495 will not be a success if the hardware does not complete its mission objectives. Faculty are eager to
see a working model. To improve something and make it work, you first must understand it
2

Agenda Introduction to the Arduino Hardware
IDE, Variables, Operands, and the Serial Monitor
Control Flow
Loops
Arrays & Strings
Functions, Structs, and Unions
Libraries/IO/Connection Diagrams/EEPROM
Group Activities, Post-490 Planning
3

Arduino Models
Arduino’s are microcontrollers: mini-computers with their own memory, disk, and processor
4

Lights on an Arduino (Arduino UNO)
4 Lights on an Arduino
1. ON Light - shows that it is powered on
2. TX Light - shows that data is being
transmitted
3. RX Light - shows that data is being received
4. L Light - an LED you are able to control in your
program
Serial Port (USB)
External Power Source (AA,
AAA Batteries)
5

Arduino Accessories & Shields
● Accessories include USB A-B cable, external power source, breadboard, resistors, variable resistors
(potentiometers), switches, wires, sensors, motors
● Shields” are add ons or accessories that extend the functionality of Arduino. The code is already written for
them
○ Ethernet Shields
○ LCD Shields
○ Motor Shields extends the number of motors you can use on an arduino from 6
○ Prototype Shield - for circuit development rather than soldering
■ Use breadboard as an alternative to this shield
○ There are many more shields including bluetooth, wireless, etc.
● Arduino models allow you to connect a battery or AC/DC converter to run without being connected to a computer
6

Basic components of the Arduino
Microcontroller
7

Control Flow
Loops
Arrays & Strings
8

The Arduino IDE
● You can retrieve the IDE from the main arduino website
(arduino.cc)
● The IDE is written in Java; however, the arduino only
accepts programs written in C. Therefore you must
program in C. The IDE acts as a C Compiler.
Must Choose Appropriate Arduino
Board before uploading programs
& choose the port on the computer
the arduino is connected to
Tip:
1. Use Auto-Format
to clean your code
spacing
2. Use Serial Plotter
to see Arduino
Output
Verify: Checks if your program compiles (syntax check)
Upload: Uploads your program to the Arduino.
New: Creates a new program file
Open: Open an existing arduino program file
Save: Allows you to save the current program
9

How are Arduino Programs Structured
void setup() {
Code to run once
}
void loop(){
Code to run repeatedly
}
Title of
Program
● Programs get saved in Documents/Arduino on your workstation
10

Declaring and Instantiating Variables
Declaring a Variable
dataType variableName;
Example:
int year;
Instantiating a Variable
Add equals sign
Example:
int year;
year = 2017;
Declaring and Instantiating
Simultaneously
Example:
int year = 2017;
For Constants
Add ‘const’ before dataType
Example:
const float pi = 3.14;
11

Scope of Variables
● Variable scope determines where the variable can be used in the sketch. There are two
variable scopes
○ Local Variables
■ Can only be used inside a function, and only appear inside that function block.
■ You won't see a local variable from the setup function in the loop function
○ Global Variables (Static Variables)
■ Can be used in ALL functions
■ Common to see them at the start of the sketch before the setup function
12

Math Operators
Standard Operators are built-in for use and can be used with
variables. Two examples below:
int x;
float y;
int z;
x = 5;
y = 2.7;
z = x+y;
What is z equal to above?
int x = 5;
float y = 2.7;
float z = x+y;
What is z equal to above?
Tip: instead of x = x + 1; you can write x += 1;
13

Using the Serial Monitor
The serial monitor allows you to see the output from the program
Located Here
1. insert Serial.begin(baudRate); to initialize the serial port
baudRate = Speed of Connection (higher is faster;
must match workstation baud). // i want that baud
default baud rate is 9600;
2. Printing to the serial monitor:
Serial.print(sum) // does not start a new line
Serial.println(sum) //starts a new line
3. Working with time
● delay(x): pauses the sketch for x milliseconds
● delayMicroseconds(x): pauses the sketch for x microseconds
● micros(): Returns the number of microseconds since the arduino was reset
● millis(): returns the number of milliseconds since the Arduino was reset
14

Output on the Serial Monitor
Tip: use // to place a comment. Examples above
Note: You cannot concatenate the Serial output
Ex.
// this won’t work
Serial.println(“The sum is” + sum); 15

Advanced Math Functions
Example
int Temperature = -7;
int value = abs(temperature);
Serial.println(value);
What does it print above?
Note: The map() and contrain() functions are
mostly used with sensors. They allow you to
keep values returned by the sensors within a
specific range that your sketch can manage
16

Generating Random Numbers
Two functions are available for working with random numbers. random() and randomSeed()
random(min, max) : returns a random number between min and max -1
random(max) : returns a random number between 0 and max -1
randomSeed(seed): Initializes the random number generator, causing it to restart at an arbitrary point in
random sequence.
17

Control Flow
Loops
Arrays & Strings
18

if control
if (condition) {
Statement 1;
Statement 2;
etc.
}
if/else control
if (condition) {
Statement 1;
Statement 2;
etc.
}
else {
Statements;
}
if/else if control
if (condition)
Statement;
else if (condition)
Statement;
else if (condition)
Statement;
else
Statement;
if (temperature > 100) {
Serial.println(“wow”!)
Serial.println(“that’s hot!”)
}
if (grade > 92) {
myGrade = ‘A’;
else
myGrade = ‘F’;
if (grade > 92) {
myGrade = ‘A’;
else if (grade > 83)
myGrade = ‘B’;
else
myGrade = ‘C’;
Example Example Example
19

Numeric Comparisons
Compound Conditions
If ((a == 1) || (b == 1)){
statements;
}
Example 1
If ((a == 1) && (b == 2)) {
statements;
}
Example 2
Negating a condition check
int a == 1;
If (!(a == 1))
Serial.println(“The ‘a’ variable is not
equal to 1”);
if(!(a ==2))
Serial.println(“The ‘a’ variable is not
equal to 2”);
Or just use
!= in the
condition 20

Using a switch statement
switch (var) {
case 23:
//do something when var equals 23
break;
case 64:
//do something when var equals 64
break;
default:
// if nothing else matches, do the default
// default is optional
break;
}
Instead of doing a lot of if and else statement, it may be useful to do a switch
switch (grade) {
case ‘A’:
Serial.println(“you got higher than a 92”);
break;
case ‘B’:
Serial.println(“You got higher than a 80”);
break;
default:
Serial.println(“You have dishonored the family”);
break;
}
Format Example
21

Control Flow
Loops
Arrays & Strings
22

for
for (statement1; condition; statement 2){
Code statements
}
while
while (condition){
Code statements
}
do while
do {
Code statements
} while (condition);
int values[5] = {10, 20, 30, 40, 50};
for (int counter = 0; counter < 5; counter ++){
Serial.print(“one value in the array is “ );
Serial.println(values[counter]);
}
Example Example Example
executes at least once, and
until condition is met
executes until condition is met
executes until condition is met
int i = 0;
while (i<3) {//hearts for days
Serial.println(“ i is : “ i);
i++;
}
int i = 0;
Serial.println(“Hi”);
do {
Serial.println(“my name is”);
if(i==0) Serial.println(“What”);
if(i==1) Serial.println(“Who”);
i++;
} while (i < 2);
Serial.println(“slicka chika slim shady”); 23

Loops Continued
Using Multiple Variables
You can initialize multiples variables in a for
statement
Example
int a,b;
For (a = 0, b = 0; a < 10; a++, b++){
Serial.print(“One value is “);
Serial.println(a);
Serial.print(“ and the other value is “);
Serial.println(b);
}
Example
int a,b;
for (a = 0; a < 10; a++){
for (b = 0; b < 10; b++){
Serial.print(“one value is “);
Serial.print(a);
Serial.print(“and the other value is “);
Serial.println(b);
}
}
Nesting Loops
You can place loops inside of another loop. The trick to using inner loop sis
that you must complete the inner loop before you complete the outer loop.
24

Controlling Loops
25
Break Statement
● You can use the break statement when you need
to break out of a loop before the condition would
normally stop the loop
Example:
int i;
for (i = 0; i <= 20; i++) {
if (i == 15)
Break;
Serial.print(“currently on iteration:”);
Serial.println(i);
}
Serial.println(“This is the end of the test”);
}
Continue Statement
● You can use the continue statement to control loops. Instead of
telling the Arduino to jump out of a loop, it tells the Arduino to stop
processing code inside the loop, but still jumps back to the start of
the loop
Example
int i;
for (i = 0; i <= 10; i++){
If ((i > 5) && (i < 10))
Continue;
Serial.print(“The value of the counter at“);
Serial.println(i);
}
Serial.println(“this is the end of the test”);

Control Flow
Loops
Arrays & Strings
26

Arrays
An array stores multiple data values of the same data type in a block of memory, allowing you to reference the variables using the
same variable name. It does it through an index value.
datatype variableName[size];
Format
Example 1:
int myarray[10]; //able to store 10 values
myarray[0] = 20; //stores values in index 0
myarray[1] = 30; // stores values in index 1
Example 2:
// assigns values to first 5 data locations (index 0-4)
Int myarray[10] = {20, 30, 40, 50, 100};
Example 3
int myarray[ ] = {20, 30, 40, 50 100};
Using Loops with Arrays
int values[5] = {10, 20, 30, 40, 50};
for (int counter = 0; counter < 5; counter ++){
Serial.print(“one value in the array is “ );
Serial.print(values[counter]);
}
27

Arrays Continued
Determining the size of an Array
● You may not remember how many
data points are in your array
● You can use the handy sizeof function
size = sizeof(myArray) / sizeof(int);
for (counter =0; counter < (sizeof(value)/sizeof(int)); counter++){
//This will only iterate through number of points in an array
statements;
}
Example:
Challenge Question 1: What is the array
‘myArray’ look like in the program below?
int myArray[3][4];
for (int i = 0; counter < 3; i ++){
for (int j = 0; j < 4; i++) {
myArray[ i ] [ j ] = 1;
}
}
Challenge Question 2: What is
syntactically wrong with the array below?
How do i fix it?
char myArray[ ] = { “mon”, “tue”, “wed”, “thu”, “fri”};
28

Strings
29
A string value is a series of characters put together to create a word or sentence
Format
String name = “my text here”;
Example
String myName = “Jackie Chan”;
Manipulating Strings
String myName = “Jackie Chan”;
myName.toUpperCase();
Output: JACKIE CHAN

More String Functions
30
Although you can just
create a char array,
Strings are much easier
to work with! They have
many more supported
functions

Control Flow
Loops
Arrays & Strings
31

Functions
32
You’ll often find yourself using the same code in multiple locations. Doing large chunks of these is a hassle. However, functions make these a
lot easier. You can encapsulate your C code into a function and then use it as many times as you want.
Structure
datatype functionName() {
// code statements
}
TIP: Make sure you define your function outside of the setup
and loop functions in your arduino code sketch. If you define a
function inside another function, the inner function becomes a
local function, and you can't use it outside the outer function
To create a function that does not return any data values to the
calling program, you use the void data type for the function
definition
Void myFunction() {
Serial.println(“This is my first function”);
}

Using the function/Returning a value
33
To use a function you defined in your sketch,
just reference it by the function name you
assigned, followed by parentheses
void setup() {
Serial.begin(9600)
MyFunction();
Serial.println(“Now we’re back to the main program”);
}
Using the Function Returning a Value
To return a value from the function back to
the main program, you end the function with
a return statement
return value;
The value can either a constant numeric or
string value, or a variable that contains a
numeric or string value. However, in either
case, the data type of the returned value
must match the data type that you use to
define the function
int myFunction2() {
int value = 10*20;
return (value);
}

Passing Values to Functions
34
void setup() {
Int returnValue;
Serial.begin(9600);
Serial.print(“The area of a 10 x 20
size room is “);
returnValue = area(10,20);
Serial.println(returnValue);
}
void loop() {
}
int area (int width, int height) {
int result = width * height;
Return result;
}
You will most likely want to pass values into
function. In the main program code, you
specify the values passed to a function in
what are called arguments, specific inside the
function parenthesis
returnValue = area(10,20);
The 10 and 20 are value arguments
separated by a comma. To retrieve the
arguments passed to a function, the function
definition must declare what are called
parameters. You do that in the main function
declaration line
Parameters
Arguments

Handling Variables inside Functions
35
One thing that causes problem for beginning sketch writers is the scope of a variable. He scope is where the variable can be referenced
within the sketch. Variables defined in function can have a different scope than regular variables. That is, they can be hidden from the rest
of the sketch. Functions use two types of variables:
Global Variables
Local Variables
Defining Global Variables
Write them before the setup() loop. Ex:
const float pi = 3.14;
Be careful in modifying global variables.
Declaring local variables
Local variables are declared in the function code itself, separate from the rest of the sketch code. What’s interesting is that a local variable
can override a global variable (but not good practice)

Calling Functions Recursively
36
Recursion is when the function calls itself to
reach an answer. Usually a recursion function
has a base value that it eventually iterates
down to. Many advanced algorithms use
recursion to reduce a complex equation down
one level repeatedly until they get to the level
defined by the base value.
int factorial (int x) {
if (x <=1) return 1;
else return x * factorial(x-1);
}
Remember you are allowed to call other
functions from inside a function

Structs
37
Data structures allow us to define custom data types
that group related data elements together into a
single object.
Before you can use a data structure in your sketch,
you need to define it. To define a data structure in
the Arduino, you can use the struct statement. Here
is the generic format for declaration
Format
struct name {
variable list
};
Example of declaration
struct sensorinfo {
char date[9];
int indoortemp;
int outdoortemp;
}morningTemps, noonTemps, eveningTemps;
struct sensorinfo {
char date[9];
int indoortemp;
int outdoortemp;
}morningTemps
void setup() {
// put your setup code here, to run once:
Serial.begin(9600);
strcpy(morningTemps.date, "01/01/14");
morningTemps.indoortemp = 72;
morningTemps.outdoortemp = 25;
Serial.print ("Today's date is ");
Serial.println(morningTemps.date);
Serial.print("The morning outdoor temperate
is ");
Serial.println(morningTemps.outdoortemp);
}
Full Example: Declaring and Calling

Unions
38
Unions allow you to have a variable take on different data types
Format
union {
//variable list
};
Example
Union {
float analogInput;
int digitalInput;
} sensorInput;
//Full Example:
Union{
float analogInput;
Int digitalInput;
}sensorInput;
//Saving a value
sensorInput.analogInput = myFunction1();
sensorInput.digitalInput = myFunction2();
//Calling a value;
Serial.println(sensorInput.analogInput);
Serial.println(sensorInput.DigitalInput);

Using Libraries
39
Libraries allow you to bundle related functions into a
single file that the Arduino IDE can compile into your
sketches. Instead of having to rewrite the functions in
your code, you just reference the library file from your
code, and all the library functions become available.
This is handy for Arduino Shields
Defining the library in your sketch
#include ‘libraryheader’
#include ‘EEPROM’
Referencing the Library Functions
Library.function()
Ex. for the EEPROM library
EEPROM.read(0);
Installing your library
1. Open the Arduino IDE
2. Select the sketch from the menu bar
3. Select Import libraries from the
submenu
4. Select Add library from the list of
menu options
Sample libraries
already installed
for call and use

Input/Output Layout on Arduino
40

Digital & Analog I/O
41
pinMode(pin, MODE);
The pinMode function requires two parameters. The
pin parameter determines the digital interface number
to set. The mode parameter determines whether the
pin operates input or output mode. There are 3 values
for interface mode setting:
INPUT - To set an interface for normal input mode
OUTPUT - To set an interface for output mode
Format Getting a reading from an input device:
analogRead(pin)
void setup (){
Serial.begin(9600);
pinMode(A1, INPUT);
}
void loop() {
float reading = analogRead(A1);
}
Complete Example

Reading Connection Diagrams
42

Writing to EEPROM
43
EEPROM is the long term memory in the Arduino. It keeps data stored even when powered off, like a USB flash drive.
Important Note: EEPROM becomes unreliable after 100,000 writes
You’ll first need to include a library file in your sketch
#include <EEPROM.h>
After you include the standard EEPROM library file, you
can use the two standard EEPROM functions in your code:
read (address) - to read the data value stored at the
EEPROM location specified by address
write (address, value) - to read values to the EEPROM
location specified by address
#include <EEPROM.h>
void setup()
{
for (int i = 0; i < 255; i++)
EEPROM.write(i, i);
}
void loop()
{
}

Debugging Applications
44
● Compiler will give you the line code(s)
● Compiler will give you the error
● The line causing problems may get
highlighted
● Look up errors online

Control Flow
Loops
Arrays & Strings
45

Group Practice Problems
46
1. Have the Arduino to create and save an excel sheet onto an SD card. Make the first row have
these cells in order:
"Sequence", "Day", "Month", "Date", "Year", "Hour", "Minute", "Second", "Temp F", "Sensor 1", "Sensor
2";
Tip: Look into the library SD.h in your IDE. There are examples of how to use each library given by the
authors (IDE>Files>Examples). Save the file as demo.csv. Use this link for more information on
connection setup.
2. Configure the time on the Arduino DS3231 board to the current time and date and save it. Then,
create a program that gets the current month, day, year, hour, minute, second, and temperature. Set the
delay to 3000 milliseconds
Tip: Search for and download the Library Sodaq_DS3231.h from your IDE. It is not a pre-installed
library but you can easily find it by searching it in your IDE library manager. There are examples of how
to use each library given by the authors (IDE>FILES>Examples).

Intro to Arduino Programming.pdf

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