Arduino - Keypad - LCD

Hardware Required

1×Arduino UNO or Genuino UNO
1×USB 2.0 cable type A/B
1×LCD I2C
1×Keypad 3x4 and 4x4 Kit
1×(Alternative) Keypad 3x4
1×(Alternative) Keypad 4x4
1×Breadboard
1×Jumper Wires
1×(Recommended) Screw Terminal Block Shield for Arduino Uno
1×(Recommended) Breadboard Shield For Arduino Uno
1×(Recommended) Enclosure For Arduino Uno

Or you can buy the following sensor kits:

1×DIYables Sensor Kit (30 sensors/displays)
1×DIYables Sensor Kit (18 sensors/displays)
Please note: These are Amazon affiliate links. If you buy the components through these links, We will get a commission at no extra cost to you. We appreciate it.

About Keypad and LCD

If you do not know about keypad and LCD (pinout, how it works, how to program ...), learn about them in the following tutorials:

Wiring Diagram

Arduino Keypad LCD Wiring Diagram

This image is created using Fritzing. Click to enlarge image

Arduino Code

/* * Created by ArduinoGetStarted.com * * This example code is in the public domain * * Tutorial page: https://arduinogetstarted.com/tutorials/arduino-keypad-lcd */ #include <Keypad.h> #include <LiquidCrystal_I2C.h> 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] = {9, 8, 7, 6}; // connect to the row pinouts of the keypad byte pin_column[COLUMN_NUM] = {5, 4, 3, 2}; // connect to the column pinouts of the keypad Keypad keypad = Keypad(makeKeymap(keys), pin_rows, pin_column, ROW_NUM, COLUMN_NUM ); LiquidCrystal_I2C lcd(0x27, 16, 2); // I2C address 0x27, 16 column and 2 rows int cursorColumn = 0; void setup(){ lcd.init(); // initialize the lcd lcd.backlight(); } void loop(){ char key = keypad.getKey(); if (key) { lcd.setCursor(cursorColumn, 0); // move cursor to (cursorColumn, 0) lcd.print(key); // print key at (cursorColumn, 0) cursorColumn++; // move cursor to next position if(cursorColumn == 16) { // if reaching limit, clear LCD lcd.clear(); cursorColumn = 0; } } }

※ NOTE THAT:

The I2C address of LCD can vary according to the manufacturers. In the code, we used 0x27 that is specified by DIYables manufacturer

Quick Steps

  • Connect Arduino to PC via USB cable
  • Open Arduino IDE, select the right board and port
  • Navigate to the Libraries icon on the left bar of the Arduino IDE.
  • Search “keypad”, then find the keypad library by Mark Stanley, Alexander Brevig
  • Click Install button to install keypad library.
Arduino keypad library
  • Search “LiquidCrystal I2C”, then find the LiquidCrystal_I2C library by Frank de Brabander
  • Click Install button to install LiquidCrystal_I2C library.
Arduino LiquidCrystal I2C library
  • Copy the above code and open with Arduino IDE
  • Click Upload button on Arduino IDE to upload code to Arduino
Arduino IDE Upload Code
  • Press some keys on keypad
  • See the result in LCD

If LCD displays nothing, see Troubleshooting on LCD I2C

Code Explanation

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

Video Tutorial

We are considering to make the video tutorials. If you think the video tutorials are essential, please subscribe to our YouTube channel to give us motivation for making the videos.

The Best Arduino Starter Kit

※ OUR MESSAGES