ESP32 - Door Sensor - Piezo Buzzer

We are going to learn how to:

Hardware Required

1×ESP-WROOM-32 Dev Module
1×Micro USB Cable
1×Door Sensor
1×Piezo Buzzer
1×Breadboard
n×Jumper Wires
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About Piezo Buzzer and Door Sensor

If you do not have knowledge of piezo buzzer and door sensor (pinout, how they work, how to connect them to ESP32, how to program for them...), learn about them in the following tutorials:

Wiring Diagram

ESP32 Door Sensor Piezo Buzzer Wiring Diagram

Image is developed using Fritzing. Click to enlarge image

ESP32 Code - Simple Sound

/* * Created by esp32io.com * * This example code is in the public domain * * Tutorial page: https://esp32io.com/tutorials/esp32-door-sensor-piezo-buzzer */ const int DOOR_SENSOR_PIN = 13; // ESP32 pin connected to door sensor's pin const int BUZZER_PIN = 3; // ESP32 pin connected to Buzzer's pin int doorState; void setup() { Serial.begin(9600); // initialize serial pinMode(DOOR_SENSOR_PIN, INPUT_PULLUP); // set ESP32 pin to input pull-up mode pinMode(BUZZER_PIN, OUTPUT); // set ESP32 pin to output mode } void loop() { doorState = digitalRead(DOOR_SENSOR_PIN); // read state if (doorState == HIGH) { Serial.println("The door is open");; digitalWrite(BUZZER_PIN, HIGH); // turn on Piezo Buzzer } else { Serial.println("The door is closed"); digitalWrite(BUZZER_PIN, LOW); // turn off Piezo Buzzer } }

Quick Steps

  • If this is the first time you use ESP32, see how to setup environment for ESP32 on Arduino IDE
  • Connect the ESP32 board to your PC via a micro USB cable
  • Open Arduino IDE, select the right ESP32 board and COM port
  • Copy the above code and paste it to Arduino IDE
  • Click Upload button on Arduino IDE to compile and upload code to ESP32 board
  • Move the magnet close to the reed switch and them move it far from the reed switch.
  • Listen to piezo buzzer's sound

Code Explanation

Read the line-by-line explanation in comment lines of source code!

ESP32 Code - Melody

/* * Created by esp32io.com * * This example code is in the public domain * * Tutorial page: https://esp32io.com/tutorials/esp32-door-sensor-piezo-buzzer */ #include "pitches.h" const int DOOR_SENSOR_PIN = 13; // ESP32 pin connected to door sensor's pin const int BUZZER_PIN = 8; // ESP32 pin connected to Buzzer's pin int doorState; // notes in the melody: int melody[] = { NOTE_E5, NOTE_E5, NOTE_E5, NOTE_E5, NOTE_E5, NOTE_E5, NOTE_E5, NOTE_G5, NOTE_C5, NOTE_D5, NOTE_E5, NOTE_F5, NOTE_F5, NOTE_F5, NOTE_F5, NOTE_F5, NOTE_E5, NOTE_E5, NOTE_E5, NOTE_E5, NOTE_E5, NOTE_D5, NOTE_D5, NOTE_E5, NOTE_D5, NOTE_G5 }; // note durations: 4 = quarter note, 8 = eighth note, etc, also called tempo: int noteDurations[] = { 8, 8, 4, 8, 8, 4, 8, 8, 8, 8, 2, 8, 8, 8, 8, 8, 8, 8, 16, 16, 8, 8, 8, 8, 4, 4 }; void setup() { Serial.begin(9600); // initialize serial pinMode(DOOR_SENSOR_PIN, INPUT_PULLUP); // set ESP32 pin to input pull-up mode } void loop() { doorState = digitalRead(DOOR_SENSOR_PIN); // read state if (doorState == HIGH) { Serial.println("The door is open"); buzzer(); } } void buzzer() { // iterate over the notes of the melody: int size = sizeof(noteDurations) / sizeof(int); for (int thisNote = 0; thisNote < size; thisNote++) { // to calculate the note duration, take one second divided by the note type. //e.g. quarter note = 1000 / 4, eighth note = 1000/8, etc. int noteDuration = 1000 / noteDurations[thisNote]; tone(BUZZER_PIN, melody[thisNote], noteDuration); // to distinguish the notes, set a minimum time between them. // the note's duration + 30% seems to work well: int pauseBetweenNotes = noteDuration * 1.30; delay(pauseBetweenNotes); // stop the tone playing: noTone(BUZZER_PIN); } }

Quick Steps

  • If this is the first time you use ESP32, see how to setup environment for ESP32 on Arduino IDE
  • Copy the above code and paste it to Arduino IDE
  • Create the pitches.h file On Arduino IDE:
  • Piezo Buzzer adds Pitches
    • Either click on the button just below the serial monitor icon and choose "New Tab", or use Ctrl+Shift+N.
    • Give file's name "pitches.h" and click "OK" button
    • Copy the below code and paste it to that file.
/************************************************* * 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 4978
  • Click Upload button on Arduino IDE to compile and upload code to ESP32 board
  • Door the door sensor
  • Listen to piezo buzzer's melody

Code Explanation

Read the line-by-line explanation in comment lines of source code!

※ NOTE THAT:

The above code using delay() function. This blocks other code during playing melody. To avoid blocking other code, use the ezBuzzer library instead. This library is designed for buzzer to beep or play memody without blocking other code.

Video Tutorial

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※ NOTE THAT:

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