Keyboard Reprogram

This example uses the Keyboard library to open a new Arduino Software (IDE) sketch window, send keyboard commands that type in the Blink example, and reprograms the board. After running this sketch and connecting pin 2 to ground using the pushbutton, the board will have a new program, Blink.

NB: When you use the Keyboard.print() command, the Arduino takes over your computer's keyboard! To insure you don't lose control of your computer while running a sketch with this function, make sure to set up a reliable control system before you call Keyboard.print(). This sketch is designed to only send Keyboard commands after digital pin 2 is pulled to ground.

Hardware Required

  • Arduino Leonardo, Micro, or Due board
  • pushbutton
  • hook-up wires
  • breadboard

Software Required

  • Arduino IDE running

Circuit

click the image to enlarge

image developed using Fritzing. For more circuit examples, see the Fritzing project page

Schematic

click the image to enlarge

Code

Connect your board to the USB port, then push the button to connect D2 with GND and initiate the sketch keyboard keypress emulation. Remember to have the Arduino Software (IDE) window selected before you press the button.

/*
  Arduino Programs Blink

 This sketch demonstrates the Keyboard library.

 For Leonardo and Due boards only.

 When you connect pin 2 to ground, it creates a new
 window with a key combination (CTRL-N),
 then types in the Blink sketch, then auto-formats the text
 using another key combination (CTRL-T), then
 uploads the sketch to the currently selected Arduino using
 a final key combination (CTRL-U).

 Circuit:
 * Arduino Leonardo, Micro, Due, LilyPad USB, or Yún
 * wire to connect D2 to ground.

 created 5 Mar 2012
 modified 29 Mar 2012
 by Tom Igoe
 modified 3 May 2014
 by Scott Fitzgerald

 This example is in the public domain

 http://www.arduino.cc/en/Tutorial/KeyboardReprogram
 */


#include "Keyboard.h"

// use this option for OSX.
// Comment it out if using Windows or Linux:
char ctrlKey = KEY_LEFT_GUI;
// use this option for Windows and Linux.
// leave commented out if using OSX:
//  char ctrlKey = KEY_LEFT_CTRL;


void setup() {
  // make pin 2 an input and turn on the
  // pullup resistor so it goes high unless
  // connected to ground:
  pinMode(2, INPUT_PULLUP);
  // initialize control over the keyboard:
  Keyboard.begin();
}

void loop() {
  while (digitalRead(2) == HIGH) {
    // do nothing until pin 2 goes low
    delay(500);
  }
  delay(1000);
  // new document:
  Keyboard.press(ctrlKey);
  Keyboard.press('n');
  delay(100);
  Keyboard.releaseAll();
  // wait for new window to open:
  delay(1000);

  // versions of the Arduino IDE after 1.5 pre-populate
  // new sketches with setup() and loop() functions
  // let's clear the window before typing anything new
  //  select all
  Keyboard.press(ctrlKey);
  Keyboard.press('a');
  delay(500);
  Keyboard.releaseAll();
  // delete the selected text
  Keyboard.write(KEY_BACKSPACE);
  delay(500);

  // Type out "blink":
  Keyboard.println("void setup() {");
  Keyboard.println("pinMode(13, OUTPUT);");
  Keyboard.println("}");
  Keyboard.println();
  Keyboard.println("void loop() {");
  Keyboard.println("digitalWrite(13, HIGH);");
  Keyboard.print("delay(3000);");
  // 3000 ms is too long. Delete it:
  for (int keystrokes = 0; keystrokes < 6; keystrokes++) {
    delay(500);
    Keyboard.write(KEY_BACKSPACE);
  }
  // make it 1000 instead:
  Keyboard.println("1000);");
  Keyboard.println("digitalWrite(13, LOW);");
  Keyboard.println("delay(1000);");
  Keyboard.println("}");
  // tidy up:
  Keyboard.press(ctrlKey);
  Keyboard.press('t');
  delay(100);
  Keyboard.releaseAll();
  delay(3000);
  // upload code:
  Keyboard.press(ctrlKey);
  Keyboard.press('u');
  delay(100);
  Keyboard.releaseAll();

  // wait for the sweet oblivion of reprogramming:
  while (true);
}

See Also


Last revision 2015/07/29 by SM

Share