#define PUL_PIN 2
#define DIR_PIN 1

#define STEPS 50
#define BUTTON_PIN 3

void setup(){
  pinMode(PUL_PIN, OUTPUT);
  pinMode(DIR_PIN, OUTPUT);
  pinMode(BUTTON_PIN, INPUT);
  
  digitalWrite(DIR_PIN, HIGH);
}

void loop(){

  if(digitalRead(BUTTON_PIN) == LOW){
    for(int i=0;i<STEPS;i++){
      digitalWrite(PUL_PIN, HIGH);
      delayMicroseconds(2000);
      digitalWrite(PUL_PIN, LOW);
      delayMicroseconds(2000);
    }
  }
}