Example Code for Raspberry Pi - Set LCD Color (C++)

Hardware Preparation

• Raspberry Pi 4B x 1
• RGB LCD KeyPad HAT x1
• HDMI Cable x1
• Display x1
• Keyboard and Mouse x1

Software Preparation

• Raspberry Pi OS
• Download DFRobot_RGB1602_RaspberryPi library (via GitHub or USB)

Wiring Diagram

Install the RGB LCD KeyPad HAT directly onto the Raspberry Pi board.

Other Preparation Work

1. Enable I2C on Raspberry Pi:
   Input sudo raspi-config in the terminal, then select Interfacing Options (or Advanced Options) → I2C → Yes → OK → Finish.
   
   
   
   
   

2. Detect the I2C address of the HAT:
   Run sudo i2cdetect -y 1 to confirm the device is recognized.
   

3. Download the library:

   • Via GitHub: git clone https://github.com/DFRobot/DFRobot_RGB1602_RaspberryPi.git
   • Via USB: Download the library to a USB drive and copy it to the Raspberry Pi.

4. Install I2C test tool: sudo apt-get install i2c-tools

5. Install Vim (optional, for code editing): sudo apt-get install vim-gtk

Sample Code

    #include "../DFRobot_RGBLCD.h"
    #include <iostream>
    #include <string>

    using namespace std;

    int main(){
      int r,g,b;

      DFRobot_RGBLCD lcd(16, 2);
      // initialize
      lcd.init();
      // Print a message to the LCD.
      lcd.print("set cllor");

      while(1){
        cout << "r:";
        cin >> r;
        cout << "g:";
        cin >> g;
        cout << "b:";
        cin >> b;

        lcd.setRGB(r, g, b);

        cout << "r = " << r
             << "g = " << g
             << "b = " << b
             << endl;
      }
      return 0;
    }

}

Result

Function: set the color of the RGB LCD screen

Result: input r: 255 g: 0 b: 0 then the screen displays red.

• To check or edit codes, you can download them to Windows and then open directly, or input the command vim SetColor.cpp under the catelogue DFRobot_RGB1602_RaspberryPi/cpp/examples in Raspberry Pi system.

Note: vim compiler needs to be installed first then you can continue the above operations. vim install command: sudo apt-get install vim-gtk

• Save and exit: press ESC key, then press shift+zz(or switch to uppercase mode and press ZZ)；

• Exit without saving: press ESC key, then type a colon, and input the command "q!".

Additional Information

• To edit the code: Run vim SetColor.cpp in the DFRobot_RGB1602_RaspberryPi/cpp/examples directory.
• Save and exit Vim: Press ESC → Shift+ZZ.
• Exit without saving: Press ESC → type :q! → press Enter.