1 Introduction to Coding

2 Example Codes A lot of example codes are given with Arduino IDE A code can often be based on a previous example rather than being created from scratch

3 Blink A simple code used to blink an LED plugged into pin 13 The following slides will go through the ‘blink’ code in detail, line by line

4 Comments The first lines of code are displayed in gray This indicates that they are comments for humans to read and not part of the actual code

5 Comments There are 2 ways to incorporate a comment into a code // - Single line comment /* */ - Multiline comment where everything between the two asterisks is part of the comment

6 Variables The next line of code introduces a variable called ‘led’ and sets it equal to 13 The name of the variable is chosen by the programmer In this case ‘x = 13’ or ‘table = 13’ would all suffice It is common to choose a variable name that correlates to what it is being used for In this case 13 will represent the pin the LED is plugged into

7 Variables The word ‘int’ preceding the variable name is used to tell the Arduino what we plan on storing in the variable ‘led’ A variable of the ‘int’ type can store any integer between 32,768 and -32,768. It cannot store a fraction or decimal A variable of the ‘long’ type has a range of -2,147,483,648 to 2,147,483,648. However, it uses up more memory In this case, in order to declare the variable ‘led’ as a ‘long’ type we would have written long led = 13; A variable of the ‘float’ type has a range of E+38 and E+38. It can contain decimals (float led = 13; )

8 Routines Each Arduino program is called a SKETCH and has two required functions, called ROUTINES. One is the ‘setup’ and one is the ‘loop’ Each routine is preceded by the word ‘void’ and followed with a set of parentheses ‘( )’ and curly braces ‘{ }’ void setup ( ) { } - All of the code within the curly braces is part of the setup and runs once when the program begins. void loop ( ) { } - This function is run AFTER the setup has finished. All of the code within the curly braces will be run repeatedly until power is removed.

9 pinMode In this routine there is only one line of code, ‘pinMode’ Each digital pin 0 – 13 can act as either an Input or an Output to your system, and needs to be declared as either This is because fundamentally Inputs and Outputs behave as opposites. An Input is ready to absorb energy sent into it by a sensor, while an Output contains higher amounts of energy waiting to be spit out and turn something on In this case pin 13 is an Output since we have an LED plugged in there. We can use the variable ‘led’ in place of the number thirteen since we already declared led = 13;

10 digitalWrite The next piece of code is the ‘void loop’ routine of the sketch Once a pin is set to output it can be set to either HIGH (5 Volts) or LOW(0 volts). This essentially means turn ON or OFF. There are two pieces of information in the line of code: the pin we want to control and whether is should be on or off We have declared led= 13 so we can write ‘led’ as the pin # HIGH means to turn on the pin, or send out 5V through pin 13

11 delay The next line of code is the ‘delay ’ function This is used when we want the Arduino to pause and not perform any action The delay is measured in microseconds, so 1000 = 1 second In this ‘loop’ the first line turns on a led plugged into pin 13, and the second line tells the controller to wait for 1 second

12 Run To compile your sketch, click the checkmark. Make sure your Arduino is plugged into an available USB port. Click the arrow to download the program to Arduino. If everything is attached correctly. The LED should blink.