Arduino Nano - Keypad - LCD

This tutorial instructs you how to use Arduino Nano to display the input from keypad on LCD display.

Hardware Preparation

1	×	Official Arduino Nano
1	×	Alternatively, DIYables ATMEGA328P Nano Development Board
1	×	USB A to Mini-B USB cable
1	×	LCD I2C
1	×	Keypad 3x4 and 4x4 Kit
1	×	Breadboard
1	×	Jumper Wires
1	×	Recommended: Screw Terminal Expansion Board for Arduino Nano
1	×	Recommended: Breakout Expansion Board for Arduino Nano
1	×	Recommended: Power Splitter for Arduino Nano

Or you can buy the following kits:

1	×	DIYables Sensor Kit (30 sensors/displays)
1	×	DIYables Sensor Kit (18 sensors/displays)

Disclosure: Some of the links provided in this section are Amazon affiliate links. We may receive a commission for any purchases made through these links at no additional cost to you.
Additionally, some of these links are for products from our own brand, DIYables .

Buy Note: Alternatively, you can assemble the LCD I2C display using LCD 1602 Display and PCF8574 I2C Adapter Module.

Overview of Keypad and LCD

If you are unfamiliar with keypad and LCD (pinout, how it works, how to program ...), the following tutorials can help you:

Wiring Diagram

This image is created using Fritzing. Click to enlarge image

See The best way to supply power to the Arduino Nano and other components.

Arduino Nano Code

/* * This Arduino Nano code was developed by newbiely.com * * This Arduino Nano code is made available for public use without any restriction * * For comprehensive instructions and wiring diagrams, please visit: * https://newbiely.com/tutorials/arduino-nano/arduino-nano-keypad-lcd */ #include <Keypad.h> #include <LiquidCrystal_I2C.h> const int ROW_NUM = 4; //four rows const int COLUMN_NUM = 3; //four columns const byte pin_rows[ROW_NUM] = {10, 9, 8, 7}; // The Arduino Nano pin connected to the row pins of the keypad const byte pin_column[COLUMN_NUM] = {6, 5, 4}; // The Arduino Nano pin connected to the column pins of the keypad char key_layout[ROW_NUM][COLUMN_NUM] = { {'1', '2', '3'}, {'4', '5', '6'}, {'7', '8', '9'}, {'*', '0', '#'} }; Keypad keypad = Keypad( makeKeymap(key_layout), pin_rows, pin_column, ROW_NUM, COLUMN_NUM); LiquidCrystal_I2C lcd(0x27, 16, 2); // I2C address 0x27 (from DIYables LCD), 16 column and 2 rows int cursorColumn = 0; void setup() { lcd.init(); // Initialize the LCD I2C display 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 address of the LCD may differ depending on the manufacturer. In our code, we have used 0x27, as specified by DIYables.

Detailed Instructions

Connect an USB cable to the Arduino Nano and the PC.
Open the Arduino IDE, select the appropriate board and port.
Click to the Libraries icon on the left bar of the Arduino IDE.
Search for “keypad” and locate the keypad library by Mark Stanley and Alexander Brevig.
Press the Install button to install the keypad library.

Search for “LiquidCrystal I2C” and locate the LiquidCrystal_I2C library created by Frank de Brabander.
Then, click the Install button to install the said library.

Copy the code and open it in Arduino IDE.
Click the Upload button on Arduino IDE to compile and upload the code to Arduino Nano.

Press certain keys on the keypad
Check out the outcome on the LCD display

If the LCD does not show anything, . check out Troubleshooting on LCD I2C for help.

Code Explanation

Check out the line-by-line explanation contained in the comments of the source code!

Video Tutorial

Learn More

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