Not able to control DC motor speed with l298N & pwm pins

Question

I am using arduino uno to control dc motor speed with L298N. But the problem is that the motor is only going at max speed. PWM pin doesn't work for some reason. I heard many people had some problem but haven't found the solution yet.

code:-

#include <L298N.h>

#define ENA 9
#define IN1 8
#define IN2 7

L298N motor(ENA, IN1, IN2);

void setup() {
// Setup pin mode

//used for display information
  Serial.begin(9600);

}

void loop() {
//Drive Motor Forward
  motor.setSpeed(10);
  motor.forward();
  delay(500);
  motor.setSpeed(100);
  motor.forward();
  delay(500);
  motor.setSpeed(255);
  motor.forward();
  delay(500);

}

I only see the motor move at full speed every time. I connected 5V of Arduino to +12V pin of motor driver and Arduino is powered with my laptop USB.

I am using 4.5V toy dc motor for test - DC motor

What could be wrong here?

Answer 1

Modifying the library code file L298N.cpp. Insert 2 lines in setSpeed():

void L298N::setSpeed(unsigned short pwmVal)
{ _pwmVal = pwmVal;
  if (_ismoving == true)                   // +++
    analogWrite(_pinEnable, _pwmVal);      // +++
}

Problem solved!

Answer 2

Try to use this code, without the library, and be shure to connect every pin to the correct arduino output! If everything is ok it should work! Check a tutorial here

int IN3 = 5;    
int IN4 = 4;     
int ENB = 3;    
void setup()
{
 pinMode (ENB, OUTPUT); 
 pinMode (IN3, OUTPUT);
 pinMode (IN4, OUTPUT);
}
void loop()
{

  digitalWrite (IN3, HIGH);
  digitalWrite (IN4, LOW);   
  analogWrite(ENB,55);
  delay(2000);
  analogWrite(ENB,105);
  delay(2000);
  analogWrite(ENB,255);
  delay(2000);
  analogWrite(ENB,0);
  delay(5000);
}