How to interface LCD with Keypad module and Arduino.

In this tutorial, we will learn how to interface a Keypad module with an Arduino Nano and display the key presses on both the serial monitor and an I2C LCD. Follow these steps to get started:

Materials Needed:

- Arduino Nano

- Keypad module (4x4 matrix)

- I2C LCD (16x2)

- Breadboard

- Jumper wires

- USB cable for Arduino Nano

Step 1: Wiring the Keypad to Arduino Nano

1. Identify the pins: Most 4x4 keypads have 8 pins, organized in rows and columns.

2. Connect the Keypad to Arduino:

- Connect the first pin of the keypad to D2 on the Arduino.

- Connect the second pin of the keypad to D3 on the Arduino.

- Connect the third pin of the keypad to D4 on the Arduino.

- Connect the fourth pin of the keypad to D5 on the Arduino.

- Connect the fifth pin of the keypad to D6 on the Arduino.

- Connect the sixth pin of the keypad to D7 on the Arduino.

- Connect the seventh pin of the keypad to D8 on the Arduino.

- Connect the eighth pin of the keypad to D9 on the Arduino.

Step 2: Wiring the I2C LCD to Arduino Nano

1. Identify the I2C pins on the LCD (usually labeled as GND, VCC, SDA, SCL).

2. Connect the I2C LCD to Arduino:

- Connect GND on the LCD to GND on the Arduino.

- Connect VCC on the LCD to 5V on the Arduino.

- Connect SDA on the LCD to A4 on the Arduino.

- Connect SCL on the LCD to A5 on the Arduino.

Step 3: Installing Required Libraries

1. Open the Arduino IDE.

2. Install the Keypad library:

- Go to `Sketch -> Include Library -> Manage Libraries`.

- Search for "Keypad" and install the library by Mark Stanley and Alexander Brevig.

3. Install the LiquidCrystal I2C library:

- Go to `Sketch -> Include Library -> Manage Libraries`.

- Search for "LiquidCrystal I2C" and install the library by Frank de Brabander.

Step 4: Writing the Code

Here’s a sample code to read key presses from the keypad and display them on both the serial monitor and the I2C LCD.

Step 5: Upload and Test

1. Connect your Arduino Nano to your computer using the USB cable.

2. Upload the code to the Arduino Nano.

3. Open the Serial Monitor from the Arduino IDE (`Tools -> Serial Monitor`) and set the baud rate to 9600.

4. Press the keys on the keypad. You should see the key presses displayed on both the serial monitor and the I2C LCD.