Including Class with .h and .cpp files I am trying to use a class in .ino file. The code is:
  .ino file

#include &lt;LED.h&gt;

int Pin1 = 13;
int Pin2 = 12;
int Pin3 = 11;
LED led;
void setup() {
  pinMode(Pin1,OUTPUT);
  pinMode(Pin2,OUTPUT);
  pinMode(Pin3,OUTPUT);
  digitalWrite(Pin1,LOW);
  digitalWrite(Pin2,LOW);
  digitalWrite(Pin3,LOW);
}

void loop() {
  led.on(Pin1);
  delay(2);
  led.on(Pin2);
  delay(2);
  led.on(Pin3);
  delay(2);
}


.h file

#ifndef LED_h
#define LED_h

class LED{
public:
    void on(int);
    void off(int);
};

#endif


.cpp file

#include &lt;stdio.h&gt;
#include &lt;Arduino.h&gt;
#include "LED.h"    

void LED::on(int PIN){
    digitalWrite(PIN,HIGH);
}

void LED::off(int PIN){
    digitalWrite(PIN,LOW);
}


Arduino compiler picks the object declaration error:

LEDC:6: error: 'LED' does not name a type
LEDC.ino: In function 'void loop()':
LEDC:17: error: 'led' was not declared in this scope

How should I declare objects in Arduino then?

The way that I am putting the files in folders is like the attached image:
That version of the IDE (it seems to change from version to version) differentiates between includes with &lt;...&gt; and includes with "...".

If you use &lt;...&gt; it only looks in the system and library areas.  If you use "..." it also looks inside your sketch.

So in your main INO file change the LED include from:

#include &lt;LED.h&gt;


To:

#include "LED.h"


and it should compile.