JSN-SR04T Waterproof Ultrasonic Module by CMMC

#include <Arduino.h>

int trigPin = 5; 
int echoPin = 4; 
long duration, cm;

void setup() {
  Serial.begin(115200);
  delay(10);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
}

void loop()
{
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2); 
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(5);  
  digitalWrite(trigPin, LOW);

  pinMode(echoPin, INPUT);
  duration = pulseIn(echoPin, HIGH);

  cm = (duration/2) / 29.1;

  Serial.print(cm);
  Serial.println("cm");
  delay(250);
}