This Here is a home work assignment over the weekend that I had for my device interface class here at UC Berkeley.  The task was to create a simple keyboard using Arduino and additional HW.  I decided to use a 5-key (direction pad) keyboard that displays the letter selected on the computer screen.  

In general, this is a fairly simple task; however, because I wanted to have the computer GUI that talked to the Arduino it made the difficulty level a little harder.  

For the first part, I just used an actual keyboard up, down, left, right arrows and enter to control the Processing GUI.  I will then convert the keyboard input to serial input from the Arduino but it should look very similar.  Here is the initial Processing Code:



//Variables

static final int enterh = 30;

PFont f;

int i, charSelect, col;

color fillUP, fillDOWN, fillLEFT, fillRIGHT, fillENTER;




String words;

String[] keyboard = {"a", "b", "c", "d", "e",

"f", "g", "h", "i", "j", "k",

"l", "m", "n", "o", "p", "q",

"r", "s", "t", "u", "v", "w",

"x", "y", "z", "space"};




//Setup Loop

void setup() {

size(400, 360);

words = "";

charSelect = 0;



col = 0;

background(1);

// Create the font

f = createFont("Ethnocentric", 20);

i=0;

background(0);

}







//Draw loop

void draw() {

background(0);

textAlign(LEFT);

textFont(f,9);

fill(255);

text("a b c d e f g h i j k l m", width/2-4*enterh, height/4);

text("n o p q r s t u v w x y z", width/2-4*enterh, height/4+16);

text("space", width/2-4*enterh, height/4+32);

textFont(f, 30);

strokeWeight(1);

stroke(255, 255, 255);

rectMode(CENTER);

fill(0);

//rect(width/2,40, 90, 40);

rectMode(CORNER);

fill(255, 0, 0);

textAlign(CENTER);

text(keyboard[charSelect], width/2, 50);

strokeWeight(4);

stroke(15, 242, 39);

fill(0);

rect(width/2-4*enterh, height/2-1.5*enterh,enterh*8, enterh*4);

stroke(237, 255, 3);

fill(fillENTER);

rect((width/2)-enterh, height/2, enterh*2, enterh);

fill(fillLEFT);

triangle((width/2)-enterh*1.66, height*.5, (width/2)-enterh*1.66, height*.5+enterh,(width/2)-(enterh*2.5), height*.5+(enterh/2));

fill(fillRIGHT);

triangle((width/2)+enterh*1.66, height*.5, (width/2)+enterh*1.66, height*.5+enterh,(width/2)+(enterh*2.5), height*.5+(enterh/2));

fill(fillUP);

triangle((width/2)-enterh, height*.5-enterh*.333, (width/2)+enterh, height*.5-enterh*.33,(width/2), height*.5-enterh);

fill(fillDOWN);

triangle((width/2)-enterh, height*.5+enterh*1.333, (width/2)+enterh, height*.5+enterh*1.33,(width/2), height*.5+enterh*2);

delay(200);

fillUP = color(0, 0, 0);

fillDOWN = color(0, 0, 0);

fillLEFT = color(0, 0, 0);

fillRIGHT = color(0, 0, 0);

fillENTER = color(0, 0, 0);

textAlign(CENTER);

textFont(f, 16);

fill(237, 255, 3);

text(words, width/2, height*.9);

//println(words);





}




void keyPressed() {

if (key == CODED)

{



if (keyCode == UP)

{

fillUP = color(255, 0, 0);

if(col>0)

col -= 1;

else

col = 2;

if(col == 2)

charSelect = 26;



else{

charSelect -= 13;

}

}

else if (keyCode == DOWN)

{

fillDOWN = color(255, 0, 0);

if(col <2)

col += 1;

else

col = 0;

if(col == 2)

charSelect = 26;

else if(col == 0)

charSelect = 0;

else

charSelect += 13;



}

else if(keyCode == LEFT)

{

fillLEFT= color(255, 0, 0);

if(charSelect>0)

charSelect--;

else

charSelect = keyboard.length-1;

}

else if(keyCode == RIGHT)

{

fillRIGHT= color(255, 0, 0);

if(charSelect<keyboard.length-1)

charSelect++;

else

charSelect = 0;

}

}

else if(key == ENTER)

{

fillENTER = color(255, 0, 0);

if(keyboard[charSelect] == "space")

words = words + " ";

else

words = words + keyboard[charSelect];

}

else

{

fillUP = color(0, 0, 0);

fillDOWN = color(0, 0, 0);

fillLEFT = color(0, 0, 0);

fillRIGHT = color(0, 0, 0);

fillENTER = color(0, 0, 0);

}

if(charSelect < 13)

col = 0;

else if(charSelect <26)

col = 1;

else

col = 2;

println(col + " " + charSelect);

}