CREATE A LIBRARY IN ARDUINO

 

In this tutorial we are going to see how to create a library in Arduino in a simple and easier method.

Prerequisite:

Basics of C and C++ language

In this example we are going to develop a LED ON and OFF using library.

CODE WITHOUT LIBRARY 

In above code, 3 LED are connected in 2, 3 and 4 pin of Arduino UNO.

Here we turn ON and OFF LED individually for 500 MS.

Here the task is ON and OFF for all the LED.

This CODE can be further simplified using Library.

CODE WITH LIBRARY

To create a library we need to create Header file, cpp files and the main code file.

The header file is saved as .h and cpp file is saved as .cpp

STEP 1: click New Tab

STEP 2: name file as led.h

STEP 3: name file as led. cpp

HEADER FILE CODE

In header file The #ifndef is a macro which is used for code protect.

The compiler checks the header file for 1^st  time it will check ,if the name is defined or NOT .

If not defined the condition is true and it process to second line

We define the name using #define macro.

If the file is accessed 2^nd time the compiler checks whether the file is defined or not, already the file is defined in 1^st time itself and the file is skipped.

 

The #include Arduino is added for access functionality of Arduino boards

Class is created with name LED

Class name – LED

In Public

  void toggle(int _delay);
  void ledpin(int led_pin);
  int PIN;

is used globally in all files.

 

CPP FILE CODE

In cpp file, first we need to add header file, #include “led.h”

The functions are defined with class name

Return type class name: function name (arguments)

MAIN CODE

In main code,first we need to include header file.

#include”led.h”

CLASS NAME Object name

LED led1, led2, led3

Here LED is class name and led1, led2 and led 3 are objects

In void setup

Object name. function name(argument);

led1 .ledpin(2);

here led1 is object name.

ledpin(2) is class function

2 is Arduino pin no passed as argument.

 

In void loop()

led1. toggle(500);

Here led1 is object name

toggle (500) is function name with delay mills are argument.

 CREATING AS LIBRARY

Save file in Documents->Arduino->Libraries ->LED (create new folder and rename as LED)

Inside LED folder

led.cpp

led.h

Examples (create new folder and rename as examples)

Examples folder -> LED (create new folder and rename as file name LED).

LED folder->LED.ino main coding file.

 

Now open Arduino IDE and Files->Examples->LED->LED

Opens LED. ino as example file.

 

 To download library file

LED Library download