#include <Stepper.h>
const int st = 200;

Stepper stepm(st, 8, 9, 10, 11);
void setup() {
  pinMode(4, OUTPUT);
  pinMode(5, OUTPUT);
  pinMode(6, OUTPUT);
  pinMode(7, INPUT);
  stepm.setSpeed(120);
  Serial.begin(9600);
}

void loop() {
  digitalWrite(6, LOW);
  delay(10);
  digitalWrite(6, HIGH);
  delay(10);
  digitalWrite(6, LOW);
  unsigned int Pulse = pulseIn(7, HIGH);
  unsigned int dis = Pulse * 0.0173681;
  Serial.print("Ult : ");
  Serial.println(dis);
  if (dis < 50){
    digitalWrite(5, HIGH);
    digitalWrite(4, LOW);
    Serial.print("Step : ");
    Serial.print(st);
    Serial.println("   ( Found )");
    stepm.step(st);
    delay(500);
    Serial.println(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>");
  }
  else {
    digitalWrite(5, LOW);
    digitalWrite(4, HIGH);
    Serial.print("Step : ");
    Serial.print(st);
    Serial.println("   ( No Found )");
    stepm.step(0);
    delay(500);
    Serial.println("<<<<<<<<<<<<<<<<<<<<<<<<<<<<<");
  }
}