Wiring
Check pinout, power supply, common GND and voltage levels before connecting the module.
Full code
const int trigPin = 5;
const int echoPin = 18;
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);
long duration = pulseIn(echoPin, HIGH);
Serial.println(duration * 0.0343 / 2);
delay(500);
}How it works
This lesson matches the page title and gives a clean starting point for this exact example.
Common mistakes
Check board selection, wiring, libraries, power supply and serial monitor baud rate.