const int dht_pin=15;
const int trigpin=2;
const int echopin=4;
float duration;
int distance;
void setup() {
  Serial.begin(115200);
  pinMode(trigpin, OUTPUT);
  pinMode(echopin, INPUT);
}
void loop() {
  digitalWrite(trigpin,LOW);
  delayMicroseconds(2);
  digitalWrite(trigpin,HIGH);
  delayMicroseconds(10);
  digitalWrite(trigpin,LOW);
  duration=pulseIn(echopin,HIGH);
  distance=duration*0.0342/2;
  Serial.println(distance);
  delay(1000);
}