#include <Stepper.h>

int stepsPerRevolution = 200;
int motSpeed = 100;
Stepper myStepper(stepsPerRevolution, 8, 9, 10, 11);
int dur = 500;

int buttonPin = 2;
int dir = 200;
int buttonValNew;
int buttonValOld = 1;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  myStepper.setSpeed(motSpeed);
  pinMode(buttonPin, INPUT);
  digitalWrite(buttonPin, HIGH);
}

void loop() {
  buttonValNew = digitalRead(buttonPin);
  if(buttonValOld == 1 && buttonValNew == 0){
    dir *= -1;
  }
  myStepper.step(dir*1);
  buttonValOld = buttonValNew;
  delay(dur);
}