Building Arduino Projects for the Internet of Things

CHAPTER 1 ■ ARDUINO BASICS

Code Construct Description

digitalWrite(...) Sets digital pin value (HIGH or LOW)

Serial.begin() Initializes serial monitor

Serial.print() Logs message on serial monitor

Serial.println() Logs message on serial monitor with new line

delay(ms) Adds a wait in processing

setup() Standard Arduino function called once

loop() Standard Arduino function called repeatedly

if Checks for a true/false condition

if ... else Checks for a true/false condition; if false goes to else

// Single-line comment

/ / Multiline comment

#define Defines a constant

#include Includes an external library

Table 1-1. (continued)

You can explore the complete language at https://www.arduino.cc/en/Reference.
The Arduino IDE provides a very simple and clean interface to write code. Normally
you would structure your code in three parts:

• External libraries: Includes all required libraries. A library is a
  fully developed and tested piece of code that you can include and
  use in your code. For instance, if you wanted to communicate
  over the Internet using an Ethernet connection, instead of writing
  all of that code from scratch, you could simply import and include
  the Ethernet library using #include <Ethernet.h>.


• Constants and variables : Defines all constants and variables
  that will be used to read and manipulate data. Constants do not
  change, so you can, for instance, use them for port numbers on
  the board. Variables can change, so they can be used for reading
  sensor data.


• Functions : Provides implementation of all custom and standard
  functions. A function encapsulates a specific functionality. It is
  recommended to put your code in functions, especially when you
  are looking to reuse that piece of code. Functions help avoid code
  duplication.

Listing 1-1 provides an example of code that is structured according to points
discussed previously.