#define trigpin 4  
#define echopin 5

int ledlow = 6; 
int ledmiddle = 7; 
int ledhigh = 8; 

void setup()
{
Serial.begin(9600);
pinMode(trigpin, OUTPUT);
pinMode(echopin, INPUT);
  pinMode(ledlow, OUTPUT); 
  pinMode(ledmiddle, OUTPUT);
  pinMode(ledhigh, OUTPUT);

  digitalWrite(ledlow, LOW); 
  digitalWrite(ledmiddle, LOW);
  digitalWrite(ledhigh, LOW);

 delay(10); 
}

void loop()
{
 int duration, distance;
 digitalWrite(trigpin, HIGH);

delayMicroseconds(10);  
digitalWrite(trigpin, LOW);


duration = pulseIn(echopin,HIGH);

distance = ( duration / 2) / 29.1;
Serial.println("cm:"); 
Serial.println(distance);
  
if(  (distance > 250) && (distance <= 400)  ) //Level High
{

  digitalWrite(ledlow, LOW); 
  digitalWrite(ledmiddle, LOW);
  digitalWrite(ledhigh, HIGH);
  Serial.print("Level High 100% ");

} else

if(  (distance > 100) && (distance <= 250)  ) //Level Middle
{

  digitalWrite(ledlow, LOW); 
  digitalWrite(ledmiddle, HIGH);
  digitalWrite(ledhigh, LOW);
  Serial.print("Level Middle 50% ");
} else

if(  (distance > 0) && (distance <= 100)  ) //Level Low
{

  digitalWrite(ledlow, HIGH); 
  digitalWrite(ledmiddle, LOW);
  digitalWrite(ledhigh, LOW);
  Serial.print("Level Low 20% ");
} else

delay(5000);
}