Arduino USB Keyboard

gistfile1.cpp

/**
 * VirtualUsbKeyboard
 *
 * Enumerates itself as a HID (Human Interface Device) to a host
 * computer using a USB shield. The Arduino then appears to the host to
 * be a USB keyboard and keypress events can be sent on demand.
 *
 * This example watches the state of 6 push buttons and when a button
 * is pressed it sends a matching keypress event to the host.
 *
 * Copyright 2009 Jonathan Oxer <jon@oxer.com.au>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version. http://www.gnu.org/licenses/
 *
 * www.practicalarduino.com/projects/easy/virtual-usb-keyboard
 */

// Requires the use of the "UsbKeyboard" library available from
//   http://code.rancidbacon.com/ProjectLogArduinoUSB
//
//   ** Note
//   Now moved to http://code.google.com/p/vusb-for-arduino/
//

/**
* Modified by Takafumi IWAI
* takafumi@tawashi.org
*/


#include "UsbKeyboard.h"

// Define the inputs to use for buttons
#define BUTTON_A 6
#define BUTTON_B 7
#define BUTTON_C 8
#define BUTTON_MSG 10

// Use the on-board LED as an activity display
int ledPin = 13;

/**
 * Configure button inputs and set up the USB connection to the host
 */
void setup()
{
  delay(1000);
  
  Serial.begin(9600);
  Serial.println("Setup");
  
  // Set up the activity display LED
  pinMode (ledPin, OUTPUT);
  digitalWrite (ledPin, LOW);

  // Set the button pins to inputs
  pinMode (BUTTON_A, INPUT);
  pinMode (BUTTON_B, INPUT);
  pinMode (BUTTON_C, INPUT);
  pinMode (BUTTON_MSG, INPUT);

  // Enable the CPU's internal 20k pull-up resistors on the button
  // inputs so they default to a "high" state
  digitalWrite (BUTTON_A, HIGH);
  digitalWrite (BUTTON_B, HIGH);
  digitalWrite (BUTTON_C, HIGH);
  digitalWrite (BUTTON_MSG, HIGH);

  // setup
  setupUSBInterrupt();
  
  // wait
  waitUntilUSBGetReady();
}


/**
 * Main program loop. Scan for keypresses and send a matching keypress
 * event to the host
 * FIXME: currently repeats as fast as it can. Add transition detection
 */
void loop()
{
  if (digitalRead(BUTTON_A) == LOW) {
    UsbKeyboard.sendKeyStroke(KEY_A);
    UsbKeyboard.sendKeyStroke(KEY_ENTER);
    delayMs(100);
  }

  if (digitalRead(BUTTON_B) == LOW) {
    UsbKeyboard.sendKeyStroke(KEY_B);
    UsbKeyboard.sendKeyStroke(KEY_ENTER);
    delayMs(100);
  }

  if (digitalRead(BUTTON_C) == LOW) {
    UsbKeyboard.sendKeyStroke(KEY_C);
    UsbKeyboard.sendKeyStroke(KEY_ENTER);
    delayMs(100);
  }

  if (digitalRead(BUTTON_MSG) == LOW) {
    UsbKeyboard.sendKeyStroke(KEY_H, MOD_SHIFT_LEFT);
    UsbKeyboard.sendKeyStroke(KEY_E);
    UsbKeyboard.sendKeyStroke(KEY_L);
    UsbKeyboard.sendKeyStroke(KEY_L);
    UsbKeyboard.sendKeyStroke(KEY_O);
    UsbKeyboard.sendKeyStroke(KEY_SPACE);
    UsbKeyboard.sendKeyStroke(KEY_W, MOD_SHIFT_LEFT);
    UsbKeyboard.sendKeyStroke(KEY_O);
    UsbKeyboard.sendKeyStroke(KEY_R);
    UsbKeyboard.sendKeyStroke(KEY_L);
    UsbKeyboard.sendKeyStroke(KEY_D);
    UsbKeyboard.sendKeyStroke(KEY_ENTER);
    delayMs(100);
  }

}


/**
 * Define our own delay function so that we don't have to rely on
 * operation of timer0, the interrupt used by the internal delay()
 */
void delayMs(unsigned int ms)
{
  for (int i = 0; i < ms; i++) {
    delayMicroseconds(1000);
  }
}

// Modified by Takafumi IWAI
void setupUSBInterrupt()
{
  // Disable timer0 since it can mess with the USB timing. Note that
  // this means some functions such as delay() will no longer work.
  TIMSK0&=!(1<<TOIE0);

  // Clear interrupts while performing time-critical operations
  cli();

  // Force re-enumeration so the host will detect us
  usbDeviceDisconnect();
  delayMs(250);
  usbDeviceConnect();

  // Set interrupts again
  sei();
}

// Added by Takafumi IWAI
void waitUntilUSBGetReady()
{
  while(true){
    for(int i = 0; i < 10; i++){
      UsbKeyboard.update();
      delayMs(5);
    }
    
    if(usbInterruptIsReady()){
      Serial.println("Now USB is ready!");
      break;
    }else{
      Serial.println("USB is not ready. Waiting...");
    }
  }
  digitalWrite(ledPin, HIGH);
}

Really Good Project. Thank You.
but how to make CTRL+ALT+DELETE?