#define ECHOPIN 3
#define TRIGPIN 2
void setup() {
  // put your setup code here, to run once:
Serial.begin(9600);
pinMode(ECHOPIN, INPUT);
pinMode(TRIGPIN, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
digitalWrite(TRIGPIN, LOW);
delayMicroseconds(2);
digitalWrite(TRIGPIN, HIGH);
delayMicroseconds(10);
digitalWrite(TRIGPIN , HIGH);
float distance = pulseIn (ECHOPIN, HIGH);
distance = distance/50;
Serial.print(distance);
Serial.print(" cm");
delay(200);
}