int trig=28;
int echo=27;
int dir=16;
int step=17;
void setup() {
 Serial.begin(115200);
pinMode(1, OUTPUT);

pinMode(trig, OUTPUT);
pinMode(echo, INPUT);

pinMode(dir, OUTPUT);
pinMode(step, OUTPUT);
}
void loop() {

  digitalWrite(trig,HIGH);
  delayMicroseconds(10);
  digitalWrite(trig, LOW);
  int time=pulseIn(echo,HIGH);
  int distance=time*0.034/2;
  Serial.println(distance);


 
 if(distance<=200){
  digitalWrite(1, HIGH);
 digitalWrite(dir, HIGH);
  for(int i=0;i<100;i++){
digitalWrite(step, HIGH);
digitalWrite(step, LOW);
delay(15);
  }

 

 delay(2000);
digitalWrite(dir, LOW);
 for(int i=0;i<100;i++){
digitalWrite(step, HIGH);
digitalWrite(step, LOW);
delay(15);
  }
 digitalWrite(1, LOW);
delay(500);
 }
}