Stepper Motor 28BYJ-48 with ULN 2003

Hello guys.
I have got one little problem with this stepper motor.
Problem is that motor is only vibrating and not turning. Can somebody help me?
Thanks

Please read the post "How to use this forum" and follow the directions.

Post the code, using code tags, and a wiring diagram.

So this is the code which I am using :

#include <Stepper_28BYJ_48.h>

#define pin1  8//these are the Arduino pins that we use to activate coils 1-4 of the stepper motor
#define pin2  9
#define pin3  10
#define pin4  11
#define delaytime 2   //delay time in ms to control the stepper motor delaytime.
                      //Our tests showed that 8 is about the fastest that can yield reliable operation w/o missing steps

char unChar;
String readString; 
float numberOfSteps = 0;
int datoserial = 0;

void setup() {
  pinMode(pin1, OUTPUT);
  pinMode(pin2, OUTPUT); 
  pinMode(pin3, OUTPUT); 
  pinMode(pin4, OUTPUT);
  Serial.begin(9600); //initialize serial comunication
}

void loop() {
  while (Serial.available()) { 
    delay(3);                  
    char c = Serial.read();  
    readString += c;         
  }
 
  if (readString.length() >0) { 
  
   Serial.println(readString.toInt()); 
    datoserial = readString.toInt();
    
  }
  while(datoserial>numberOfSteps){
             
         backward();
         delayMicroseconds(40);
         numberOfSteps = numberOfSteps + 1;
    
  }
 while(datoserial<numberOfSteps){
         
          forward();
          delayMicroseconds(40);
          numberOfSteps = numberOfSteps - 1;
    
  }
  
  if (readString == "SET"){
    numberOfSteps = 0;
    datoserial = 0;
    }
 
  readString=""; 
}

And this is the code for function of motor:

//Function to control each pin of stepper motor

void Step_A(){
  digitalWrite(pin1, HIGH);//turn on coil 1 
  digitalWrite(pin2, HIGH); 
  digitalWrite(pin3, LOW); 
  digitalWrite(pin4, LOW); 
}
void Step_B(){
  digitalWrite(pin1, LOW); 
  digitalWrite(pin2, HIGH);//turn on coil 2
  digitalWrite(pin3, HIGH); 
  digitalWrite(pin4, LOW); 
}
void Step_C(){
  digitalWrite(pin1, LOW); 
  digitalWrite(pin2, LOW); 
  digitalWrite(pin3, HIGH); //turn on coil 3
  digitalWrite(pin4, HIGH); 
}
void Step_D(){
  digitalWrite(pin1, HIGH); 
  digitalWrite(pin2, LOW); 
  digitalWrite(pin3, LOW); 
  digitalWrite(pin4, HIGH); //turn on coil 4
}
void step_OFF(){
  digitalWrite(pin1, LOW); //power all coils down
  digitalWrite(pin2, LOW); 
  digitalWrite(pin3, LOW); 
  digitalWrite(pin4, LOW); 
}

//these functions run the above configurations in forward and reverse order
//the direction of a stepper motor depends on the order in which the coils are turned on.
void forward(){//one tooth forward
  Step_A();
  delay(delaytime);
  Step_B();
  delay(delaytime);
  Step_C();
  delay(delaytime);
  Step_D();
  delay(delaytime);
}

void backward(){//one tooth backward
  Step_C();
  delay(delaytime);
  Step_B();
  delay(delaytime);
  Step_A();
  delay(delaytime);
  Step_D();
  delay(delaytime);
}

And this is the schematic which I’m using:

According to your diagram, you have not connected the ground of the motor power supply to the Arduino ground.