ESP32 - Keypad - Beep

When a key on the keypad is pressed, the piezo buzzer beeps. Without delay() function for beeping, there is no keypad's press missed.

Hardware Required

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

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

The ezBuzzer library is designed for buzzer to beep or play memody without blocking other code.

Wiring Diagram

ESP32 keypad piezo buzzer wiring diagram

Image is developed using Fritzing. Click to enlarge image

ESP32 Code

/* * Created by esp32io.com * * This example code is in the public domain * * Tutorial page: https://esp32io.com/tutorials/esp32-keypad-beep */ #include <Keypad.h> #include <ezBuzzer.h> const int BUZZER_PIN = 23; // GIOP23 connect to the buzzer's pin const int ROW_NUM = 4; // four rows const int COLUMN_NUM = 4; // four columns char keys[ROW_NUM][COLUMN_NUM] = { {'1', '2', '3', 'A'}, {'4', '5', '6', 'B'}, {'7', '8', '9', 'C'}, {'*', '0', '#', 'D'} }; byte pin_rows[ROW_NUM] = {19, 18, 5, 17}; // GIOP19, GIOP18, GIOP5, GIOP17 connect to the row pins byte pin_column[COLUMN_NUM] = {16, 4, 0, 2}; // GIOP16, GIOP4, GIOP0, GIOP2 connect to the column pins Keypad keypad = Keypad(makeKeymap(keys), pin_rows, pin_column, ROW_NUM, COLUMN_NUM ); ezBuzzer buzzer(BUZZER_PIN); // create ezBuzzer object that attach to a pin; void setup() { Serial.begin(9600); } void loop() { buzzer.loop(); // MUST call the buzzer.loop() function in loop() char key = keypad.getKey(); if (key) { Serial.print(key); // prints key to serial monitor buzzer.beep(100); // generates a 100ms beep } }

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
  • On Arduino IDE, Go to Tools Manage Libraries
  • ESP32 add library
  • Search “keypad”, then find the keypad library by Mark Stanley, Alexander Brevig
  • Click Install button to install keypad library.
  • ESP32 keypad library
  • Search “ezBuzzer”, then find the buzzer library by ESP32GetStarted
  • Click Install button to install ezBuzzer library.
  • ESP32 buzzer library
  • Copy the above code and paste it to Arduino IDE
  • Click Upload button on Arduino IDE to compile and upload code to ESP32 board
  • Arduino IDE Upload Code
  • Press some keys on keypad
  • Listen the beep and see the result in Serial Monitor

Code Explanation

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

Video Tutorial

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