#define trig 9
#define echo 10
#define motor1 5
#define motor2 6
 
int speed = 0;
int ultra(int trg, int ech){
  while(1){
  digitalWrite(trg, LOW);
  delayMicroseconds(2);
  digitalWrite(trg, HIGH);
  delayMicroseconds(10);
  digitalWrite(trg, LOW);+
  int duration = pulseIn(ech,HIGH,5000);
  int distance = duration * 0.034/2;
  if(distance != 0){
  return distance;}
  }
}
 
void setup() {
  pinMode(trig,OUTPUT);
  pinMode(echo,INPUT);
  pinMode(motor1, OUTPUT);
  pinMode(motor2, OUTPUT);
  Serial.begin(9600);
 
}
 
void loop() {

  int a = ultra(trig,echo);
  Serial.println(a);
  if (a > 40){
  analogWrite(motor1, 255);
  digitalWrite(motor2, LOW);
  int a = ultra(trig,echo);
  }
else if (a > 35 and a < 40){
  analogWrite(motor1, 125);
  analogWrite(motor2, 0);
  int a = ultra(trig,echo);
}

else if (a > 30 and a < 35){
  analogWrite(motor1, 63);
  analogWrite(motor2, 0);
  int a = ultra(trig,echo);
}

else if (a < 30 and a > 20){
  digitalWrite(motor1, 0);
  analogWrite(motor2, 0);
  int a = ultra(trig,echo);
}
 


else if (a < 20){
  digitalWrite(motor1, 0);
  digitalWrite(motor2, 1);
}

}