int r=11;
int echo=2;
int o=12;
int trig=3;
int y=13;
int time;
int distance;

void setup() {
  // put your setup code here, to run once:
pinMode(y, OUTPUT);
pinMode(o, OUTPUT);
pinMode(r, OUTPUT);
pinMode(trig, OUTPUT);
pinMode(echo, INPUT);

}

void loop() {
  // put your main code here, to run repeatedly:
digitalWrite(trig, HIGH);
delayMicroseconds(10);
digitalWrite(trig, LOW);
delayMicroseconds(10);

time = pulseIn(echo,HIGH);
distance = 0.0343*time/2;

if(distance>1 && distance<=10)
{
digitalWrite(o, LOW);
digitalWrite(r, LOW);
digitalWrite(y, HIGH);
}
else 
  digitalWrite(o, LOW);
  digitalWrite(r, LOW);
  digitalWrite(y, LOW);

if(distance>10 && distance<=20)
{
digitalWrite(o, HIGH);
digitalWrite(y, HIGH);
digitalWrite(r, LOW);
}
else
 digitalWrite(o, LOW);
  digitalWrite(r, LOW);
  digitalWrite(y, LOW);

if(distance>20 && distance<=30)
{
digitalWrite(o, HIGH);
digitalWrite(y, HIGH);
digitalWrite(r, HIGH);
}
else
  digitalWrite(o, LOW);
  digitalWrite(r, LOW);
  digitalWrite(y, LOW);

}