#define PIN_TRIG 26
#define PIN_ECHO 25
#define LOWLED 18
#define MIDLED 19
#define HIGHLED 21
#define MOTOR 27


unsigned int level =0;

void setup(){

  pinMode(LOWLED,OUTPUT);
  pinMode(MIDLED,OUTPUT);
  pinMode(HIGHLED,OUTPUT);
  pinMode(MOTOR,OUTPUT);
  digitalWrite(LOWLED,HIGH);
  digitalWrite(MIDLED,HIGH);
  digitalWrite(HIGHLED,HIGH);
  digitalWrite(MOTOR,LOW);

  Serial.begin(115200);
  pinMode(PIN_TRIG, OUTPUT);
  pinMode(PIN_ECHO, INPUT);
}

void loop(){

  digitalWrite(PIN_TRIG,HIGH);
  delayMicroseconds(10);
  digitalWrite(PIN_TRIG,LOW);

  //READ THE RESULT
  int duration = pulseIn(PIN_ECHO,HIGH);
  Serial.print("Distance in CM:");
  Serial.println(duration/58);
  Serial.print("Distance in inches:");
  Serial.println(duration/148);
  level =duration/58;

  if(level<100)
  {
    digitalWrite(LOWLED,LOW);
    digitalWrite(MOTOR,HIGH);
    digitalWrite(HIGHLED,HIGH);
    digitalWrite(MIDLED,HIGH);
  }

  else if((level>=100) && (level<300)){
    digitalWrite(LOWLED, HIGH);
    digitalWrite(HIGHLED, HIGH);
    digitalWrite(MIDLED,LOW);
  }

  else if((level>=300) && (level<=400)){
    digitalWrite(HIGHLED,LOW);
    digitalWrite(MIDLED,HIGH);
    digitalWrite(LOWLED,HIGH);
    digitalWrite(MOTOR,LOW);
  }
  delay(1000);
}