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Welcome

In this project, we will use a PIR sensor to detect human presence and a speaker to simulate a doorbell, similar to the entrance doorbells in convenience stores. When a pedestrian appears within the range of the PIR sensor, the speaker will ring, mimicking a doorbell.

Required Components

In this project, we need the following components.

It’s definitely convenient to buy a whole kit, here’s the link:

Name	ITEMS IN THIS KIT	LINK
Elite Explorer Kit	300+	Elite Explorer Kit

You can also buy them separately from the links below.

COMPONENT INTRODUCTION	PURCHASE LINK
Arduino Uno R4 WiFi	-
Breadboard	BUY
Jumper Wires	BUY
Resistor	BUY
PIR Motion Sensor Module	BUY
Audio Module and Speaker	-

Wiring

Schematic

Code

Note

You can open the file 01_welcome.ino under the path of elite-explorer-kit-main\fun_project\01_welcome directly.
Or copy this code into Arduino IDE.
The pitches.h file is also required — place it in the same directory.

pitches.h

/*****************
Public Constants
*****************/
#define NOTE_B0  31
#define NOTE_C1  33
#define NOTE_CS1 35
#define NOTE_D1  37
#define NOTE_DS1 39
#define NOTE_E1  41
#define NOTE_F1  44
#define NOTE_FS1 46
#define NOTE_G1  49
#define NOTE_GS1 52
#define NOTE_A1  55
#define NOTE_AS1 58
#define NOTE_B1  62
#define NOTE_C2  65
#define NOTE_CS2 69
#define NOTE_D2  73
#define NOTE_DS2 78
#define NOTE_E2  82
#define NOTE_F2  87
#define NOTE_FS2 93
#define NOTE_G2  98
#define NOTE_GS2 104
#define NOTE_A2  110
#define NOTE_AS2 117
#define NOTE_B2  123
#define NOTE_C3  131
#define NOTE_CS3 139
#define NOTE_D3  147
#define NOTE_DS3 156
#define NOTE_E3  165
#define NOTE_F3  175
#define NOTE_FS3 185
#define NOTE_G3  196
#define NOTE_GS3 208
#define NOTE_A3  220
#define NOTE_AS3 233
#define NOTE_B3  247
#define NOTE_C4  262
#define NOTE_CS4 277
#define NOTE_D4  294
#define NOTE_DS4 311
#define NOTE_E4  330
#define NOTE_F4  349
#define NOTE_FS4 370
#define NOTE_G4  392
#define NOTE_GS4 415
#define NOTE_A4  440
#define NOTE_AS4 466
#define NOTE_B4  494
#define NOTE_C5  523
#define NOTE_CS5 554
#define NOTE_D5  587
#define NOTE_DS5 622
#define NOTE_E5  659
#define NOTE_F5  698
#define NOTE_FS5 740
#define NOTE_G5  784
#define NOTE_GS5 831
#define NOTE_A5  880
#define NOTE_AS5 932
#define NOTE_B5  988
#define NOTE_C6  1047
#define NOTE_CS6 1109
#define NOTE_D6  1175
#define NOTE_DS6 1245
#define NOTE_E6  1319
#define NOTE_F6  1397
#define NOTE_FS6 1480
#define NOTE_G6  1568
#define NOTE_GS6 1661
#define NOTE_A6  1760
#define NOTE_AS6 1865
#define NOTE_B6  1976
#define NOTE_C7  2093
#define NOTE_CS7 2217
#define NOTE_D7  2349
#define NOTE_DS7 2489
#define NOTE_E7  2637
#define NOTE_F7  2794
#define NOTE_FS7 2960
#define NOTE_G7  3136
#define NOTE_GS7 3322
#define NOTE_A7  3520
#define NOTE_AS7 3729
#define NOTE_B7  3951
#define NOTE_C8  4186
#define NOTE_CS8 4435
#define NOTE_D8  4699
#define NOTE_DS8 49

01_welcome.ino

/*
  The code is for an Arduino project that plays a melody when motion is detected by 
  a PIR (Passive Infrared) motion sensor. 

  Board: Arduino Uno R4 
  Component: PIR Motion Sensor Module, Audio Module, and Speaker
*/

#include "analogWave.h"
#include "pitches.h"

analogWave wave(DAC);

#define PIR_PIN 8

int melody[] = {
  NOTE_C4, 4, NOTE_E4, 4, NOTE_G4, 4, NOTE_C5, 4, NOTE_G4, 4, NOTE_E4, 4, NOTE_C4,4
};

int noteCounter = 0;
int bpm = 60;
float beatDuration = 60.0 / bpm * 1000;
int divider = 0, noteDuration = 0;  // Variables to hold note duration

void setup() {
  Serial.begin(9600);
  pinMode(PIR_PIN, INPUT);  // Set PIR motion sensor pin as input
  wave.sine(10);
}

void loop() {
  int pirValue = digitalRead(PIR_PIN);  // Read the PIR sensor
  Serial.println(pirValue);
  
  if (pirValue == HIGH) {
    playMelody();
    delay(5000);  // wait for 5 seconds before checking again to avoid repetitive playing
  }
}

void playMelody() {
  // Calculate the duration of the current note
  while (1) {
    divider = melody[noteCounter + 1];
    if (divider > 0) {
      // For regular notes
      noteDuration = beatDuration / divider;
    } else if (divider < 0) {
      // For dotted notes (duration increased by 50%)
      noteDuration = beatDuration / abs(divider);
      noteDuration *= 1.5;  // Increase the duration by 50% for dotted notes
    }

    // Play the note
    wave.freq(melody[noteCounter]);
    delay(noteDuration * 0.85);  // Play the note for 85% of its duration
    wave.stop();

    // Pause between notes
    delay(noteDuration * 0.15);  // Pause for 15% of the note duration

    // Increment the note counter by 2 (because each note is followed by its duration)
    noteCounter += 2;

    // Reset the counter when reaching the end of the melody
    int totalNotes = sizeof(melody) / sizeof(melody[0]);
    noteCounter = noteCounter % totalNotes;

    // Exit the loop after the melody finishes playing
    if (noteCounter == 0) {
      break;
    }
  }
}

How it works?

Here is a step-by-step explanation of the code:

Include Header Files:

Include two header files, analogWave.h and pitches.h. The analogWave.h file contains the definition of the analogWave class, while pitches.h contains the definitions of musical notes.
Instantiate Objects and Define Constants:

Create a wave object using the analogWave class and define PIR_PIN as 2, which is the pin connected to the PIR sensor.
Melody Array:

The melody array defines a musical melody, with each note followed by a number representing its duration. Negative numbers represent dotted notes (increasing the duration by 50%).
Global Variables:

Define some global variables for sharing data between functions.
setup():

Initialize PIR_PIN as an input and set the frequency of the sine wave to 10 Hz using wave.sine(10).
loop():

Continuously monitor the value of the PIR sensor. If human presence is detected (pirValue is HIGH), call the playMelody() function to play the melody and wait for 10 seconds to prevent repetitive playback of the melody.
playMelody():

This function calculates the duration of each note based on the data in the melody array and plays the corresponding note. There is a brief pause between notes. The function sets the frequency of the waveform using wave.freq() and controls the duration of the notes and pauses between notes using the delay() function.

Note: Ensure that the pitches.h header file indeed exists before running this code.