#define TRIG_PIN 2
#define ECHO_PIN 3
long duration, cm, inches;
void setup() {
Serial.begin(9600);
pinMode(TRIG_PIN, OUTPUT);
pinMode(ECHO_PIN, INPUT);
}
void loop() {
digitalWrite(TRIG_PIN, LOW);
delayMicroseconds(5);
digitalWrite(TRIG_PIN, HIGH);
delayMicroseconds(10);
digitalWrite(TRIG_PIN, LOW);
duration = pulseIn(ECHO_PIN, HIGH);
cm = (duration / 2) / 29.1; // Divide by 29.1 or multiply by 0.0343
inches = (duration / 2) / 74; // Divide by 74 or multiply by 0.0135
Serial.print(inches);
Serial.print("in, ");
Serial.print(cm);
Serial.print("cm");
Serial.println();
delay(500);
}
hc-sr04_ultrasonic_sensor_module_eng.pdf