#include <Keyboard.h>

// Define the GPIO pins for CTRL+A, CTRL+B, CTRL+C, and CTRL+D keys
#define A_PIN 2
#define B_PIN 3
#define C_PIN 4
#define D_PIN 5

void setup() {
// Set up the GPIO pins as inputs with pull-up resistors
pinMode(A_PIN, INPUT_PULLUP);
pinMode(B_PIN, INPUT_PULLUP);
pinMode(C_PIN, INPUT_PULLUP);
pinMode(D_PIN, INPUT_PULLUP);

// Initialize the keyboard library
Keyboard.begin();
}

void loop() {
// Check if the CTRL+A pin is pressed
if (digitalRead(A_PIN) == LOW) {
// Press and release the CTRL+A key combination
Keyboard.press(KEY_LEFT_CTRL);
Keyboard.press(‘a’);
delay(50);
Keyboard.releaseAll();
}

// Check if the CTRL+B pin is pressed
if (digitalRead(B_PIN) == LOW) {
// Press and release the CTRL+B key combination
Keyboard.press(KEY_LEFT_CTRL);
Keyboard.press(‘b’);
delay(50);
Keyboard.releaseAll();
}

// Check if the CTRL+C pin is pressed
if (digitalRead(C_PIN) == LOW) {
// Press and release the CTRL+C key combination
Keyboard.press(KEY_LEFT_CTRL);
Keyboard.press(‘c’);
delay(50);
Keyboard.releaseAll();
}

// Check if the CTRL+D pin is pressed
if (digitalRead(D_PIN) == LOW) {
// Press and release the CTRL+D key combination
Keyboard.press(KEY_LEFT_CTRL);
Keyboard.press(‘d’);
delay(50);
Keyboard.releaseAll();
}

// Wait for a short period of time before checking the pins again
delay(10);
}