How to Create Library for Arduino using C / C ++ ??
Click below link to download (.pdf):
Date :
14 June 2K19
Author
: Jaydeep
Shah (E.C Engineer)
Blog : https://radhey04ec.blogspot.com Email : radhey04ec@gmail.com
A Library typically consist of three main components :
1) Header File (.h) = This contain the
Library definitions .
2) Source code (.cpp) =
This is c++ file contain library’s code.
3) Keyword file (.txt) =
This contain that are used in library.
-
First of all .ino (Arduino code file ) ,
.h Header file & .cpp Source code file must be in same folder.
I have used DevC++ Software to write down the code , You can use any of C or C++
software or text editor like notepad+ (2.0) etc.
Let’s start step by step, I have covered two different
examples in this book.
Example 1 :
I want to make program using my own Library. Just user
need to enter pin number of LED and delay time between blinking of LED. No need
to declaration as OUTPUT pin etc. Let’s start.
1) Header file:
#include
“Arduino.h”
/* This declaration allows you to use Arduino functions like a HIGH,digitalWrite etc.*/
/* This declaration allows you to use Arduino functions like a HIGH,digitalWrite etc.*/
void
blinkLED(int pin,int delayTime);
/* Function definition so you can call it from source file & can use in Arduino code. */
/* Function definition so you can call it from source file & can use in Arduino code. */
SaveAS above file as a “myLib.h”
2) Source Code:
#include
“Arduino.h”
#include
“myLib.h”
// Calling to header file
// Calling to header file
void blinkLED(int pin,int delayTime)
// Create function body
{
pinMode(pin,OUTPUT); // Declare pin as output pin
digitalWrite(pin,HIGH); // Pin output HIGH
delay(delayTime); // delay time as per user input
digitalWrite(pin,LOW); // Pin output LOW
delay(delayTime);
}
SaveAs ‘myLib.cpp’ in same folder.
3) Making .ino Arduino file in Arduino
IDE :
#include
“myLib.h” // Call
to our library
void
setup()
{
}
void loop()
{
blinkLED(13,100);
// call to our function – declaration of op pin and delay
}
Save above code and Exit from Arduino IDE. Make sure all the file mustbe inside of same folder location. Again open it and load the code into your Arduino. It will work !!!!
User can use
your blinkLED function , no
extra activity require.
When you debug / load the program you can see your .h file and .cpp file with .ino file
in Arduino
IDE.If there will error then you can reed it directly from Arduino IDE and
save it for further debigging process.
Good Luck !!!
For Download soft copy (.pdf) Click below Link :
In Example-1 , I have used simple method for declaring
function .But in real time problems we have to use and deal with many
complicated calculation and Function's call .
Example – 02 :
- - 2
Leds connected with pin no 03 , 05
- - Make
Library for this program
- - Turn
All LEDs on & Turn All LEDs off
- - Flash
all LEDs 4 times
Let’s
start :
1) Header File : Code :
#ifndef
myFirstLib_h
#define myFirstLib_h
#include “Arduino.h”
class myFirstLib {
public :
myFirstLib(int pinOne,int PinTwo);
void on();
void off();
void flash(int delaytime);
private:
int _pinOne;
int _pinTwo;
};
#endif
Lets understand step by step….
·
#ifndef - This is combination of
if and endif loop. ifndef statement check to see if myFirstLib.h is not already
defined in library package. It stop double declaration of any identifiers within same library.
This statement act as Guard / Security for your program.
>> Keywords :
Reserve words for compiler / All have special meaning in program and in
compiler.
Ex:
if, else ,for ,int ,char etc.
>> Identifiers :
Name given to Entity / Object into Program
Ex : int money : Here money
is Identifier (name of varaible / Array etc)
·
#define myFirstLib_h – This statement defines this is header file, so you can use it in Source file and .ino file.
#define myFirstLib_h – This statement defines this is header file, so you can use it in Source file and .ino file.
· #include “Arduino.h” – Because of this statement you can use Arduino’s Library functions like delay, HIGH or LOW, digitalWrite , pinMode etc.
· class myFirstLib { - This is class declaration where all varaibles ,functions stored .
· public : - Class property is public : so you can access data from anywhere.
· myFirstLib(int pinOne,int Pin Two) :- This is the first statement of the class known as Constructor .
Constructor : This is special member function of class that is eexecuted whenever we create new objectof class.
-
Constructor always have same name as class
name.
-
It doesn’t have any return type at all
even void.
· void on(), void off() ,void flash(int delayTime) : These three are Function declaration , all these functions available for user call. Definition body of these functions store into source file.
· private : Declaration of private class , access within class itself.
·
}; - end
of the class
·
#endif -
Wrap all above task within #ifndef function : End of Guard
2) Source File declaration :
#include
“Arduino.h”
#include “myFirstLib.h”
myFirstLib :: myFirstLib(int pinOne, int pinTwo)
{
pinMode(pinOne,OUTPUT);
pinMode(pinTwo,OUTPUT);
_pinOne=pinOne;
_pinTwo=pinTwo;
}
void myFirstLib :: on() {
digitalWrite(_pinOne,HIGH);
digitalWrite(_pinTwo,HIGH);
}
void myFirstLib :: off() {
digitalWrite(_pinOne,LOW);
digitalWrite(_pinTwo,LOW);
}
void
myFirstLib :: flash(int delayTime) {
for (int i = 0; i < 4; i++)
{
digitalWrite(pinOne,HIGH);
digitalWrite(pinTwo,HIGH);
delay(delayTime);
digitalWrite(pinOne,LOW);
digitalWrite(pinTwo,LOW);
delay(delayTime);
}
}
We have to undersatnd this code stap by step, Let’s start ….
·
#include “myFirstLib.h” : Calling our header file
#include “myFirstLib.h” : Calling our header file
·
myFirstLib :: myFirstLib(int pinOne, int pinTwo) : First word myFirstLib
is name of class. :: sign
indicate that you can access and use all functions and constructor. Second word
myFirstLib(int pinOne, int pinTwo) indicate
that we are dealing with constructor.
· Body of Constructor when call it :
{
pinMode(pinOne,OUTPUT);
pinMode(pinTwo,OUTPUT);
_pinOne=pinOne;
_pinTwo=pinTwo;
}
Everytime you need to
create object / entity before using any
functions. we will see it in Arduino code.
·
Body of Second Function :
void myFirstLib :: on() {
digitalWrite(_pinOne,HIGH);
digitalWrite(_pinTwo,HIGH);
}
Here class name = myFirstLib
Function name = on()
:: Indicate that you function and class relation.
Same for remaining functions.
3) Arduino .ino file
#include
“myFirstLib.h”
myFirstLib mysetup(13,12); // Create object mysetup from class
void
setup()
{
// For flash fourtime write down mysetup.flash(); here
}
void
loop()
{
mysetup.on(); // or use mysetup.off()
}
·
#include “myFirstLib.h” : Call to our Library header file .h
#include “myFirstLib.h” : Call to our Library header file .h
·
myFirstLib mysetup(13,12);
: Creating object (instance) mysetup and providing pin number information 13 and
12 . This object is from class myFirstLib.
This is part of constructor
declaration in cpp source file. Further we will use mysetup (instance) entity
to call any functions.
· mysetup.on(); : call the function on() using entity mysetup
mysetup.on() is use for calling
function.
Same way we can use and call other functions.Before calling function we will have to create instance first then we can call function using instance.
After all completing this process , you need to save
.h header file and .cpp source code file in same folder and then .zip it.
Now go to Arduino
IDE.
Sketch >> Include Library >> Include zip file
Select your file and load the program into your
Arduino board.
Enjoy
!!!
This book Dedicate
to : SATI………
Author Details :
JAYDEEP SHAH (E.C
ENGINEER)
AHMEDABAD – INDIA
CONTACT :
Email : radhey04ec@gmail.com
Website :
Facebook :
/shahjaydeep.jayshah
Thanks...............................
