#define motor1 5
#define motor2 6

int ultra_sonic(int trigger, int echo){
  digitalWrite(trigger, LOW);
  delayMicroseconds(2);
  digitalWrite(trigger, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigger, LOW);
  int duration = pulseIn(echo, HIGH, 50000);
  int distance = duration * 0.034 / 2;
  return distance;
}

void setup() {
  Serial.begin(9600);
  pinMode(9, OUTPUT);
  pinMode(10, INPUT);
  pinMode(3, OUTPUT);
  pinMode(5, OUTPUT);
}

void loop(){
  int distance = ultra_sonic(9, 10);
  if (distance > 30){
    for (int i = 0; i<=255; i++){
      analogWrite(motor2, i);
      digitalWrite(motor1, 0);
      if(distance < 30){
          break;
      }
      delay(10);
      distance = ultra_sonic(9, 10);
      Serial.print("distance1: ");
      Serial.println(distance);
      while(i == 255){
        digitalWrite(motor2, HIGH);
        digitalWrite(motor1, LOW);
        distance = ultra_sonic(9, 10);
        if(distance < 30){
          break;
        }
        Serial.print("distance: ");
        Serial.println(distance);
      }
    }
  }
  else{
    analogWrite(motor1, 0);
    analogWrite(motor2, 0);
  }
}