const int led = 8;
const int led2 = 9;
const unsigned int PIN_TRIG = 7;
const unsigned int PIN_ECHO = 6;
const unsigned int BAUD_RATE = 9600;
void setup() {
  Serial.begin(9600);
  pinMode(PIN_TRIG, OUTPUT);
  pinMode(PIN_ECHO, INPUT);
  pinMode(led, OUTPUT);
  pinMode(led2, OUTPUT);
}
void loop() {
   digitalWrite(PIN_TRIG,LOW);
   delayMicroseconds(2);
   digitalWrite(PIN_TRIG,HIGH);
   delayMicroseconds(10);
   digitalWrite(PIN_TRIG, LOW);

   const unsigned int duration = pulseIn(PIN_ECHO, HIGH);
   int distance = duration/29/2;

   if (duration == 0) {
     Serial.println("Warning =: no pluse from sensor");
   }
   else {
   Serial.print("Distance in CM: ");
   Serial.println(distance);
   Serial.println("cm");
}
delay(100);

if (distance < 50) { digitalWrite(led, HIGH);}
else {digitalWrite(led,LOW);}
if (distance < 30) { digitalWrite(led2, HIGH);}
else {digitalWrite(led2, LOW);}
}