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ESP32 - Potentiometer Triggers Piezo Buzzer
This tutorial instructs you how to use ESP32 and the potentiometer to control the piezo buzzer. In detail:
- The ESP32 automatically turns the piezo buzzer on if the potentiometer's analog value is above a threshold
- The ESP32 automatically turns the piezo buzzer off if the potentiometer's analog value is under a threshold
We also learn how to convert the analog value to voltage and then use the voltage threshold to control the piezo buzzer:
- The ESP32 automatically turns the piezo buzzer on if the potentiometer's voltage is above a threshold.
- The ESP32 automatically turns the piezo buzzer off if the potentiometer's voltage is under a threshold.
We will use piezo buzzer to make sound and melody of song.
Hardware Used In This Tutorial
| 1 | × | ESP-WROOM-32 Dev Module | |
| 1 | × | Micro USB Cable | |
| 1 | × | Potentiometer | |
| 1 | × | Piezo Buzzer | |
| 1 | × | Breadboard | |
| 1 | × | Jumper Wires | |
| 1 | × | (Optional) DC Power Jack | |
| 1 | × | (Optional) ESP32 Screw Terminal Adapter |
Or you can buy the following sensor kit:
| 1 | × | DIYables Sensor Kit 30 types, 69 units |
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Introduction to Piezo Buzzer and Potentiometer
We have specific tutorials about piezo buzzer and potentiometer. Each tutorial contains detailed information and step-by-step instructions about hardware pinout, working principle, wiring connection to ESP32, ESP32 code... Learn more about them at the following links:
Please note that this tutorial use 3-5V buzzer, but you can adapt it for 12v buzzer. you can learn about ESP32 - Buzzer tutorial
Wiring Diagram
This image is created using Fritzing. Click to enlarge image
ESP32 Code - Simple Sound - Analog Threshold
/*
* This ESP32 code is created by esp32io.com
*
* This ESP32 code is released in the public domain
*
* For more detail (instruction and wiring diagram), visit https://esp32io.com/tutorials/esp32-potentiometer-triggers-piezo-buzzer
*/
#define POTENTIOMETER_PIN 36 // ESP32 pin GPIO36 (ADC0) connected to Potentiometer pin
#define BUZZER_PIN 21 // ESP32 pin GPIO21 connected to Buzzer's pin
#define ANALOG_THRESHOLD 1000
void setup() {
pinMode(BUZZER_PIN, OUTPUT); // set ESP32 pin to output mode
}
void loop() {
int analogValue = analogRead(POTENTIOMETER_PIN); // read the input on analog pin
if (analogValue > ANALOG_THRESHOLD)
digitalWrite(BUZZER_PIN, HIGH); // turn on Piezo Buzzer
else
digitalWrite(BUZZER_PIN, LOW); // turn off Piezo Buzzer
}
Quick Instructions
- If this is the first time you use ESP32, see how to setup environment for ESP32 on Arduino IDE.
- Do the wiring as above image.
- Connect the ESP32 board to your PC via a micro USB cable
- Open Arduino IDE on your PC.
- Select the right ESP32 board (e.g. ESP32 Dev Module) and COM port.
- Copy the above code and paste it to Arduino IDE.
- Compile and upload code to ESP32 board by clicking Upload button on Arduino IDE
- Rotate the potentiometer
- Listen to piezo buzzer's sound
Line-by-line Code Explanation
The above ESP32 code contains line-by-line explanation. Please read the comments in the code!
ESP32 Code - Simple Sound - Voltage Threshold
The analog value read from the potentiometer is converted to voltage, and then the voltage is compared to a voltage threshold. If it exceeds the threshold, it triggers Piezo Buzzer
/*
* This ESP32 code is created by esp32io.com
*
* This ESP32 code is released in the public domain
*
* For more detail (instruction and wiring diagram), visit https://esp32io.com/tutorials/esp32-potentiometer-triggers-piezo-buzzer
*/
#define POTENTIOMETER_PIN 36 // ESP32 pin connected to Potentiometer pin
#define BUZZER_PIN 21 // ESP32 pin GPIO21 connected to Buzzer's pin
#define VOLTAGE_THRESHOLD 2.5 // Voltages
void setup() {
pinMode(BUZZER_PIN, OUTPUT); // set ESP32 pin to output mode
}
void loop() {
int analogValue = analogRead(POTENTIOMETER_PIN); // read the input on analog pin
float voltage = floatMap(analogValue, 0, 1023, 0, 5); // Rescale to potentiometer's voltage
if (voltage > VOLTAGE_THRESHOLD)
digitalWrite(BUZZER_PIN, HIGH); // turn on Piezo Buzzer
else
digitalWrite(BUZZER_PIN, LOW); // turn off Piezo Buzzer
}
float floatMap(float x, float in_min, float in_max, float out_min, float out_max) {
return (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;
}
ESP32 Code - Melody - Voltage Threshold
/*
* This ESP32 code is created by esp32io.com
*
* This ESP32 code is released in the public domain
*
* For more detail (instruction and wiring diagram), visit https://esp32io.com/tutorials/esp32-potentiometer-triggers-piezo-buzzer
*/
#include "pitches.h"
#define POTENTIOMETER_PIN 36 // ESP32 pin GPIO36 (ADC0) connected to Potentiometer pin
#define BUZZER_PIN 21 // ESP32 pin GPIO21 connected to Buzzer's pin
#define VOLTAGE_THRESHOLD 2.5 // Voltages
// 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() {
}
void loop() {
int analogValue = analogRead(POTENTIOMETER_PIN); // read the input on analog pin
float voltage = floatMap(analogValue, 0, 1023, 0, 5); // Rescale to potentiometer's voltage
if (voltage > VOLTAGE_THRESHOLD)
playMelody(); // play a song
}
float floatMap(float x, float in_min, float in_max, float out_min, float out_max) {
return (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;
}
void playMelody() {
// 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 Instructions
- 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:
- 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
- Compile and upload code to ESP32 board by clicking Upload button on Arduino IDE
- Rotate the potentiometer
- Listen to piezo buzzer's melody
Line-by-line Code Explanation
The above ESP32 code contains line-by-line explanation. Please read the comments in the code!
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