int trigpin = 2;
int echopin = 3;
int duration;
int distance;

void setup(){
  Serial.begin(115200);
  pinMode(trigpin, OUTPUT); 
  pinMode(echopin, INPUT);
}
void loop(){
  digitalWrite(trigpin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigpin, LOW);
  duration = pulseIn(echopin, HIGH);
  distance = 0.034*duration/2;
  Serial.println(distance);

}