Ultrasonic Distance 21

Measure obstacle distance with trigger and echo timing.

/*
  Roboda verified Arduino sample 0507
  Feature: Ultrasonic Distance
  Generated for online build, classroom practice, and hardware upload testing.
*/

const byte trigPin = 11;
const byte echoPin = 2;

void setup() {
  Serial.begin(9600);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
}

void loop() {
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  unsigned long duration = pulseIn(echoPin, HIGH, 30000UL);
  float distanceCm = duration * 0.0343 / 2.0;
  Serial.println(distanceCm);
  delay(360);
}

How it works

Measure distance with an ultrasonic trigger/echo module.

1. Wire TRIG and ECHO to the listed pins.
2. Send a short trigger pulse.
3. Measure echo pulse time with pulseIn().
4. Convert travel time into distance in centimeters.

Connections