Arduino Introduction

const int trigPin = 9;

const int echoPin = 10;

float duration, distance;

void setup() {

  pinMode(trigPin, OUTPUT);

  pinMode(echoPin, INPUT);

  Serial.begin(9600);

}

void loop() {

    /* sending a sound wave */

    digitalWrite(trigPin, LOW);

    delayMicroseconds(2);

    digitalWrite(trigPin, HIGH);

    delayMicroseconds(10);

    digitalWrite(trigPin, LOW);

    /* If we know when does the sound wave bounce back, it is possible to know the distance */

    duration = pulseIn(echoPin, HIGH);

    distance = (duration * 0.0343) / 2;

    Serial.print("Distance: ");

    Serial.println(distance);

    delay(100);

}

void setup() {

  pinMode(7,OUTPUT);

}

void loop() {

  digitalWrite(7,HIGH);  // turn on the buzzer

  delay(1000);

  digitalWrite(7,LOW);  // turn off the buzzer

  delay(2000);

}

#include "pitches.h"

const int buzzer = 8;

// these constants are defined in "pitches.h"

int melody[] = {

  NOTE_C4, NOTE_G3, NOTE_G3, NOTE_A3, NOTE_G3, 0, NOTE_B3, NOTE_C4

};

// note durations: 4 = quarter note, 8 = eighth note, etc.:

int noteDurations[] = {

  4, 8, 8, 4, 4, 4, 4, 4

};

void setup() {

  for (int i = 0; i < 8; i++) {

    // to calculate the note duration, take one second divided by the note type.

    int noteDuration = 1000 / noteDurations[i];

    // pin number: 8 (any pin number you want)

    //  sound frequency: melody[i]

    //  duration: noteDuration

    tone(buzzer, melody[i], noteDuration);

    // the note's duration + 30% seems to work well:

    delay(noteDuration * 1.30);

    // stop the tone playing:

    noTone(buzzer);

  }

}

void loop() {}