#define  PIN_TRIG 26
#define  PIN_ECHO 25
void setup(){
  Serial.begin(115200);
  pinMode(PIN_TRIG, OUTPUT);
  pinMode(PIN_ECHO, INPUT);
}
void loop(){
  digitalWrite(PIN_TRIG, HIGH);
  delayMicroseconds(10);
  digitalWrite(PIN_TRIG,LOW);
  int duration = pulseIn(PIN_ECHO,HIGH);
  int c ( duration*0.034/2);
Serial.println(c);delay(1000);
}