#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() {
  Serial.begin(115200);
  pinMode(PIN_TRIG, OUTPUT);
  pinMode(PIN_ECHO, INPUT);
  pinMode(LOWLED, OUTPUT);
  pinMode(MIDLED, OUTPUT);
  pinMode(HIGHLED, OUTPUT);
  pinMode(MOTOR, OUTPUT);
  //
  digitalWrite(LOWLED, HIGH);
  digitalWrite(MIDLED, HIGH);
  digitalWrite(HIGHLED, HIGH);
  digitalWrite(MOTOR, LOW);
   
}

void loop() {
  // Start a new measurement:
  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);
  }
  if(level<100){
    digitalWrite(LOWLED, LOW);
    digitalWrite(MOTOR, HIGH);
  }
  if(level<100){
    digitalWrite(LOWLED, LOW);
    digitalWrite(MIDLED, HIGH);
    digitalWrite(HIGHLED, HIGH);
    digitalWrite(MOTOR, HIGH);
  }
  else if((level>200)&&(level<400))
  {
    digitalWrite(LOWLED, HIGH);
    digitalWrite(MIDLED, LOW);
    digitalWrite(HIGHLED,  HIGH);
    digitalWrite(MOTOR, LOW);
  }
  else if(level>400)
  {
    digitalWrite(LOWLED, HIGH);
    digitalWrite(MIDLED, HIGH);
    digitalWrite(HIGHLED, LOW);
    digitalWrite(MOTOR, LOW);
  }

  delay(1000);
}