How to install, use and also create an Arduino library?

Introduction

The library is a list of functions that simplify the using of a sensor or a component.
When an Arduino program begins by #include, then it is called a library.

What a library is used for?

A library is not essential in your program. Nevertheless, the library will help you to manipulate your component or to reduce your program.  Itโ€™s simplest to use the library than re-write the functionalities in your program.

When install a library?

During the compilation of the Arduino program, the interface verify that the library is available.If the library is not included in the program, you can see the following message : โ€œLibrairie.h: No such file or directoryโ€.

If you see other error message, you can resolve it thanks to our course about the problem of upload or compiling.

How to install an Arduino Library

Method 1

You click on โ€œmanage librariesโ€:

 

In the manager of Library, you can enter the library you want and download it:

Method 2 : Import a library .zip

 

You can import directly a library from your computer by clicking on the file manager:

Where to find the .zip libraries?

There are many ways to find a library for a component. First when you find a program on internet, it is possible that the library is given with it, like in our courses for example.

Nevertheless, if you want to do your own program, there is a website with all the libraries.

Some useful libraries

Here is the list of the most useful libraries to write your program :

Component
LibraryCourse
IR RemoteIRremote.zipCourse
Temperature sensor DHT11DHT.zipCourse
Clock module DS3131DS3231.zipCourse
Distance sensor HC-SR04HC-SR04.zipCourse
KeypadKeypad.zipCourse
LCDLiquidCrystal.zipCourse
RfidRfid.zipCourse
Servo motorServo.zipCourse
Stepper motorStepper.zipCourse

If you donโ€™t find the library for your program, you can create your own library !

Create an Arduino library

To create your own Arduino library, you have to program it in C++ language. You have to use a different editor than Arduino IDE. We advise you to install codeBlock software to program the library. Before programming the Arduino library, you have to know that it is composed of a files .h and .ccp Now we will take the program of Bluetooth IR Remote as an example:
To reduce this code thanks to a library, we need to regroup the program in functions.
Then we will se in codeBlocks how to write our library to simplify the code. We need to create two files : .h and ccp :
  • File .h : It is used to defined the functions that we will put into the library
  • File .ccp : We will write the functions here.
In our case, this is the .cpp file :
#include "Arduino Factory.h"

Arduino Factory::program() {
if (Serial.available() > 0){
c = Serial.read();
switch (c) {
//--------------button 0 pin RX-------------
case 'Q':
digitalWrite(button_0, HIGH);
break;
case 'R':
digitalWrite(button_0,LOW);
default:
break;
}
}
}

We will define the functions that will be in the file .h :

#ifndef ARDUINOFACTORY_H_INCLUDED
#define ARDUINOFACTORY_H_INCLUDED
class Arduino Factory
{
public:
void program();
};

#endif // ARDUINOFACTORY_H_INCLUDED

Once both files are done, you can zip it into a folder. This folder will be your new library. You just have to import it in Arduino IDE and call it in your program:

#include <Arduinofactory.h> // The library we have just created
#define button_0 0
char c=0;
uint16_t NA;

void setup() {
pinMode(button_0, OUTPUT);
Serial.begin(9600);
analogReference(INTERNAL);
}

void loop() {
Arduinofactory.program(); // The function that we have created in .ccp file
}