Interface Keypad With Arduino

In embedded devices one of the essential part is Keypad is used to interact with embedded devices ,Keypad is input devices which is used to give commend the devices,from calculator to computer input is given through keypad,in this tutorial you will know how to interface keypad with arduino ,arduino is a mini computer which is user-friendly,we can hack anything using arduino,let see how to interface 3x4 matrix keypad with arduino.

This keypad has 12 button,which is arranged in telephonic order in 3x4 matrix you need only 7 pins to interface with micro-controller that 3 columns and 4 rows.Which has more applications like electronic door lock-calculator etc.

Step 1: INTERFACING CIRCUIT:

Keypad consist of 7 pin- in which 3 from keypad columns and 4 from keypad rows.

COLUMNS:-

colum 0 - to arduino pin 12

colum 1 - to arduino pin 11

colum 2 - to arduino pin 10

ROW:-

row 0 - to arduino pin 9

row 1 - to arduino pin 8

row 2 - to arduino pin 7

row 3 - to arduino pin 8

When you press keypad button respective key value will display in virtual terminal

Step 2: ARDUINO CODE: DOWNLOAD KEYPAD LIBRARY

#include

const byte ROWS = 4; // Four rows

const byte COLS = 3; // Three columns

// Define the Keymap

char keys[ROWS][COLS] = { {'1','2','3'}, {'4','5','6'}, {'7','8','9'}, {'#','0','*'} };

// Connect keypad ROW0, ROW1, ROW2 and ROW3 to these Arduino pins.

byte rowPins[ROWS] = { 9, 8, 7, 6 };

// Connect keypad COL0, COL1 and COL2 to these Arduino pins.

byte colPins[COLS] = { 12, 11, 10 };

// Create the Keypad Keypad kpd = Keypad( makeKeymap(keys), rowPins, colPins, ROWS, COLS );

#define ledpin 13

void setup()

{

pinMode(ledpin,OUTPUT);

digitalWrite(ledpin, HIGH);

Serial.begin(9600);

}

void loop()

{

char key = kpd.getKey();

if(key) // Check for a valid key.

{

switch (key)

{

case '1':

Serial.println(key);

break;

case '2':

Serial.println(key);

break;

case '3':

Serial.println(key);

break;

case '4':

Serial.println(key);

break;

case '5':

Serial.println(key);

break;

case '6':

Serial.println(key);

break;

case '7':

Serial.println(key);

break;

case '8':

Serial.println(key);

break;

case '9':

Serial.println(key);

break;

case '0':

Serial.println(key);

break;

case '*':

Serial.println(key);

break;

case '#':

Serial.println(key);

break;

}

}

}

Step 3: Working Output

Comments

[AJAYN33]

correct this line in the code
// Create the Keypad Keypad kpd = Keypad( makeKeymap(keys), rowPins, colPins, ROWS, COLS );
remove the comment and write it as:
Keypad kpd = Keypad( makeKeymap(keys), rowPins, colPins, ROWS, COLS );

[MohammadrezaM4]

How can use 2 digtal number keypad
Like 21 or 32 and more
Please help me

[aarafmj718]

what is kpd.getKey(); pls explain.....

[IndraN4]

the code should be:

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

.......

.......

........

char keys = keypad.getKey();

then compile success

[sanjayS116]

keys will show an error...try this!!

char key = keypad.getKey();

[ea. k]

char key = kpd.getKey();

this code is wrong!!!!

[Ollymarchington]

I got the same error