Interface 4×4 Matrix Keypad with Arduino and Buzzer

We have seen how a Matrix keypad works and How to use it with Arduino in the last tutorial. This tutorial explains how to use this keypad with a Buzzer.

Let’s connect Arduino with a buzzer and program it to perform this action ‘when a particular key press happens the Buzzer will Beep for 1 second. You can also connect a Relay to control it by keypad.

Connect the hardware to the Arduino as shown in the circuit diagram given below.

Now to turn ON the buzzer when the 5^th key is pressed we need to include the following code. In the if loop the key value is compared. If the pressed key is 5 then the buzzer connected at pin 3 turned ON for 1000 milliseconds and then Turned OFF (To avoid continuous beep sound). In setup, we need to define the buzzer pin connected at pin 3.

if (key == 5){

Serial.println(key); //Prints the key in serial monitor

digitalWrite (buzz_pin,HIGH);

Serial.println(Buzzer ON);

delay(1000);

digitalWrite (buzz_pin,LOW);

Serial.println(Buzzer OFF);

}

The following code will print the key pressed to the serial monitor and when you press the key 5 the buzzer Turns ON and Turns OFF after 1 second. For understanding, we print the buzzer status using Serial Monitor.

#include <Keypad.h>

int buzz_pin = 3;

const byte ROWS = 4; //four rows

const byte COLS = 4; //four columns

char keys[ROWS][COLS] = {

  {'1','2','3','A'},

  {'4','5','6','B'},

  {'7','8','9','C'},

  {'*','0','#','D'}   

};

byte rowPins[ROWS] = {13, 12, 11, 10}; //connect to the row pinouts of the keypad

byte colPins[COLS] = {9, 8, 7, 6}; //connect to the column pinouts of the keypad


Keypad keypad = Keypad( makeKeymap(keys), rowPins, colPins, ROWS, COLS );


void setup(){

      Serial.begin(9600);

     pinMode(buzz_pin, OUTPUT);

}

void loop(){

  char key = keypad.getKey();  //Variable to store pressed key


  if (key){

    Serial.println(key); //Prints the key in serial monitor

delay(1000);

  }

  if (key == 5){

  Serial.println(key); //Prints the key in serial monitor

digitalWrite (buzz_pin,HIGH);// Turn ON Buzzer

Serial.println(Buzzer ON);

delay(1000);

digitalWrite (buzz_pin,LOW); //Turn OFF Buzzer

Serial.println(Buzzer OFF);

  }

}