4×4 Matrix 16 Keyboard Keypad

4x4 Matrix Membrane Keypad -16 Keys

This DC 12V 4×4 Matrix Keypad Membrane Switch is high-quality soft touch feeling button keypad with 100 million life-stroke lifespans and good resistance to environmental conditions.

This DC 12V 4×4 Key Matrix Membrane Switch Keypad is a high-quality product at very low cost for your application needs.

This 16-button keypad provides a useful human interface component for microcontroller projects. Convenient adhesive backing provides a simple way to mount the keypad in a variety of applications.

The Keypad 4×4 features a total of 16 buttons in Matrix form. This is a membrane keypad with no moving parts. A female 8-pin berg connector is require for interfacing it with your microcontroller circuits.

Note: The product image may vary in terms of color

Technical Details

• Item Type: Keypad Module
• Model Type: Switch Keypad
• Operating Voltage (VDC): 35
• Operating Current (mA): 100
• Contact Resistance: 500Ω
• Insulation Resistance (MOhm): 100
• Dielectric Strength: 250VRms
• Length (mm): 165
• Width (mm): 70
• Height (mm): 1
• Weight (g): 7

Features

• Ultra-thin design & adhesive backing provides easy integration to any project
• Excellent price-performance ratio
• Easy communication with any microcontroller
• 5 pins 2.54mm pitch connector, 4x 4type 16 keys
• Sticker can peel off for adhesive mounting
• Used widely in industrial and home electronic equipments, instrument, etc.
• This allows a microcontroller to ‘scan’ the 8 output pins to see which of the 16 buttons is being pressed

Applications :

• Password-Protected Locks: Used for secure access systems.
• Home Automation: Control devices via keypad inputs.
• Menu Navigation: Navigate options in embedded systems.
• Data Entry: Input numerical or custom data in microcontroller projects.
• Industrial Controls: Provide simple input for machines and equipment.
• Gaming Consoles: Customizable inputs for gaming interfaces.
• Alarm Systems: Arming/disarming security alarms.
• Robotics: Command robot operations manually.
• DIY Projects: Flexible interface for hobbyist applications.
• Vending Machines: Key-based selection for products.

Integration with Arduino of 4 by 4 keypad

 

Sample Code

#include <Wire.h>

#include <LiquidCrystal_I2C.h>

#include <Keypad.h>

const byte ROWS = 4;

const byte COLS = 4;

char hexaKeys[ROWS][COLS] = {

{'1', '2', '3', 'A'},

{'4', '5', '6', 'B'},

{'7', '8', '9', 'C'},

{'*', '0', '#', 'D'}

};

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

byte colPins[COLS] = {5, 4, 3, 2};

Keypad customKeypad = Keypad(makeKeymap(hexaKeys), rowPins, colPins, ROWS, COLS);

LiquidCrystal_I2C lcd(0x27, 16, 2);

void setup(){ //https://kitsguru.myshopify.com/products/4x4-matrix-keypad-membrane-switch-arduino-arm-mcu

lcd.backlight();

lcd.init();

}

void loop(){

char customKey = customKeypad.getKey();

if (customKey){

lcd.clear();

lcd.setCursor(0, 0);

lcd.print(customKey);

}

}

//Credits : https://osoyoo.com/2017/09/13/arduino-lesson-4x4-matrix-keypad/

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Integration with Raspberry Pi

Sample Code

import RPi.GPIO as GPIO

import time

# These are the GPIO pin numbers where the

# lines of the keypad matrix are connected

L1 = 5

L2 = 6

L3 = 13

L4 = 19

# These are the four columns

C1 = 12

C2 = 16

C3 = 20

C4 = 21

# The GPIO pin of the column of the key that is currently

# being held down or -1 if no key is pressed

keypadPressed = -1

secretCode = "4789"

input = ""

# Setup GPIO

GPIO.setwarnings(False)

GPIO.setmode(GPIO.BCM)

GPIO.setup(L1, GPIO.OUT)

GPIO.setup(L2, GPIO.OUT)

GPIO.setup(L3, GPIO.OUT)

GPIO.setup(L4, GPIO.OUT)

# Use the internal pull-down resistors

GPIO.setup(C1, GPIO.IN, pull_up_down=GPIO.PUD_DOWN)

GPIO.setup(C2, GPIO.IN, pull_up_down=GPIO.PUD_DOWN)

GPIO.setup(C3, GPIO.IN, pull_up_down=GPIO.PUD_DOWN)

GPIO.setup(C4, GPIO.IN, pull_up_down=GPIO.PUD_DOWN)

# This callback registers the key that was pressed

# if no other key is currently pressed

def keypadCallback(channel):

global keypadPressed

if keypadPressed == -1:

keypadPressed = channel

# Detect the rising edges on the column lines of the

# keypad. This way, we can detect if the user presses

# a button when we send a pulse.

GPIO.add_event_detect(C1, GPIO.RISING, callback=keypadCallback)

GPIO.add_event_detect(C2, GPIO.RISING, callback=keypadCallback)

GPIO.add_event_detect(C3, GPIO.RISING, callback=keypadCallback)

GPIO.add_event_detect(C4, GPIO.RISING, callback=keypadCallback)

# Sets all lines to a specific state. This is a helper

# for detecting when the user releases a button

def setAllLines(state):

GPIO.output(L1, state)

GPIO.output(L2, state)

GPIO.output(L3, state)

GPIO.output(L4, state)

def checkSpecialKeys():

global input

pressed = False

GPIO.output(L3, GPIO.HIGH)

if (GPIO.input(C4) == 1):

print("Input reset!");

pressed = True

GPIO.output(L3, GPIO.LOW)

GPIO.output(L1, GPIO.HIGH)

if (not pressed and GPIO.input(C4) == 1):

if input == secretCode:

print("Code correct!")

# TODO: Unlock a door, turn a light on, etc.

else:

print("Incorrect code!")

# TODO: Sound an alarm, send an email, etc.

pressed = True

GPIO.output(L3, GPIO.LOW)

if pressed:

input = ""

return pressed

# reads the columns and appends the value, that corresponds

# to the button, to a variable

def readLine(line, characters):

global input

# We have to send a pulse on each line to

# detect button presses

GPIO.output(line, GPIO.HIGH)

if(GPIO.input(C1) == 1):

input = input + characters[0]

if(GPIO.input(C2) == 1):

input = input + characters[1]

if(GPIO.input(C3) == 1):

input = input + characters[2]

if(GPIO.input(C4) == 1):

input = input + characters[3]

GPIO.output(line, GPIO.LOW)

try:

while True:

# If a button was previously pressed,

# check, whether the user has released it yet

if keypadPressed != -1:

setAllLines(GPIO.HIGH)

if GPIO.input(keypadPressed) == 0:

keypadPressed = -1

else:

time.sleep(0.1)

# Otherwise, just read the input

else:

if not checkSpecialKeys():

readLine(L1, ["1","2","3","A"])

readLine(L2, ["4","5","6","B"])

readLine(L3, ["7","8","9","C"])

readLine(L4, ["*","0","#","D"])

time.sleep(0.1)

else:

time.sleep(0.1)

except KeyboardInterrupt:

print("\nApplication stopped!")

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Physical Attributes of 4 by 4 keypad

• Length (mm): 165
• Width (mm): 70
• Height (mm): 1
• Weight (g): 7

Package Includes

• 1 x 4x4 Matrix Membrane Keypad -16 Keys