#define trigpin3
#define echopin4
int trigpin=3;
int echopin=4;
long duration;
int distance;
void setup()
{
  pinMode(trigpin,OUTPUT);
  pinMode(echopin,INPUT);
  Serial.begin(9000);
}
void loop()
{
  digitalWrite(trigpin,LOW);
  delay(2000);
  digitalWrite(trigpin,HIGH);
  delay(1000);
  digitalWrite(trigpin,LOW);
  duration=pulseIn(echopin,HIGH);
  distance=(duration*0.034)/2;
  Serial.println("Distance:");
  Serial.println(distance);
  Serial.println("CM");
  delay(1000);
}