ian-arduino/4button-keyboard.ino

/*THE WORKING VERSION OF THE 4 BUTTON KEYBOARD
  LAYOUT
  RedWire->|
  |
  ____________
  | L1   L2  |
  |          |
  |          |
  | L3   L4  |
  |          |
  ------------
  |  |
  |  |
  ----
  L1 = buttonState3, b4, v1, var + 5
  L2 = buttonState1, b2, v3, var - 1
  L3 = buttonState, b1, v2, var + 1
  L3 = buttonState2, b3, v4, var + 10
 */
//Ints for counting multipress
int v1 = 0;
int v2 = 0;
int v3 = 0;
int v4 = 0;
//ints for button pins (only b1 - 4 are in use)
const int b1 = 2;
const int b2 = 3;
const int b3 = 4;
const int b4 = 5;
const int b5 = 6;
const int b6 = 7;
//int for counting number and submit
int var = 0;
int subvar = 0;
//Not sure what this does, but don't want to delete it
int ptrue = 0;
//ints for counting button presses
int buttonState = 0;
int lastButtonState = 0;
int buttonState1 = 0;
int lastButtonState1 = 0;
int buttonState2 = 0;
int lastButtonState2 = 0;
int buttonState3 = 0;
int lastButtonState3 = 0;
//ints for debouncing each button
long debounceDelay = 50;
long lastDebounceTime = 0;
int state = 0;
long lastDebounceTime1 = 0;
int state1 = 0;
long lastDebounceTime2 = 0;
int state2 = 0;
long lastDebounceTime3 = 0;
int state3 = 0;
/* the pins are set up as inputs and then set high,
   so that when the button is grounded it will notice it
   and count it as a button press.  this way, there are
   no resistors needed for the curcuit.
   The button should be connected from the pin, to the
   button, to ground, like this:
   PIN# --> Pin1 of button |--| -- Ground
   ^
   Button  |
 */
void setup() {
  Serial.begin(9600);
  Serial.println("Begin Typing");
  pinMode(b1, INPUT);
  pinMode(b2, INPUT);
  pinMode(b3, INPUT);
  pinMode(b4, INPUT);
  pinMode(b5, INPUT);
  pinMode(b6, INPUT);
  digitalWrite(b1, HIGH);
  digitalWrite(b2, HIGH);
  digitalWrite(b3, HIGH);
  digitalWrite(b4, HIGH);
  digitalWrite(b5, HIGH);
  digitalWrite(b6, HIGH);
}
void loop() {
  state3 = digitalRead(b4); //read if grounded or not
  if ((millis() - lastDebounceTime3) > debounceDelay) { //if the button has not been pressed within debouncetime, do...
    buttonState3 = digitalRead(b4);
    if (buttonState3 != lastButtonState3) {  //if the button is different from before (it was pessed) do...
      if (buttonState3 == HIGH) { //if the switch was released, do...
        lastDebounceTime3 = millis();
        v1 = 0;  //reset the multipress counter, so it does not count it as a press after you release the button
      }
      else {  //if switch pressed, do...
        var = var + 5;  //setting for what the button does
        lastDebounceTime3 = millis(); //reset the last debounce
        v1 = 1;  //set multipress variable to one, or, pressed
      }
    }
  }
  //the same goes for this
  state = digitalRead(b1);
  if ((millis() - lastDebounceTime) > debounceDelay) {
    buttonState = digitalRead(b1);
    if (buttonState != lastButtonState) {
      if (buttonState == HIGH) {
        lastDebounceTime = millis();
        v2 = 0;
      }
      else {
        var = var + 1;
        lastDebounceTime = millis();
        v2 = 1;
      }
    }
  }
  //and this
  state1 = digitalRead(b2);
  if ((millis() - lastDebounceTime1) > debounceDelay) {
    buttonState1 = digitalRead(b2);
    if (buttonState1 != lastButtonState1) {
      if (buttonState1 == HIGH) {
        lastDebounceTime1 = millis();
        v3 = 0;
      }
      else {
        var = var - 1;
        lastDebounceTime1 = millis();
        v3 = 1;
      }
    }
  }
  //... and this
  state2 = digitalRead(b3);
  if ((millis() - lastDebounceTime2) > debounceDelay) {
    buttonState2 = digitalRead(b3);
    if (buttonState2 != lastButtonState2) {
      if (buttonState2 == HIGH) {
        lastDebounceTime2 = millis();
        v4 = 0;
      }
      else {
        var = var + 10;
        lastDebounceTime2 = millis();
        v4 = 1;
      }
    }
  }
  characters = ['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'];
  if (subvar == 1) {
    if (var <= sizeof(characters) && var > 0) {
      Serial.print(characters[var - 1]);
    }
    subvar = 0;
    var = 0;
  }
  // this whole section controls what letters correspond to what numbers,
  // and when to send the letter out
  if (var == 1) { //if the variable is 1,
    if (subvar == 1) { //and, if you pressed the submit button,
      Serial.print('A'); //print the letter 'A' (A is the first letter in the alphabet)
      subvar = 0; //reset the submit button so it doesnt happen forever
      var = 0; //reset the variable, so you can count to the next word.
    }
  }
  // i know everything above could've been done with a map, but, i didn't do it like that.
  //this next code part control all the multipress.
  if (v1 == 1) {  //if one of the two buttons in the multipress section was pressed,
    if (v3 == 1) { //and the second button in the multipress section was pressed,
      subvar = 1;  //do what you want that multipres section to do.  In this case, it was
      //presss the top two buttons to submit the number.
      v1 = 0; //reset multipress button stats
      v3 = 0; //ya, again
      var = var - 5;  //take into account what would normall happen to the variable.
      //the top two button can add + 5 and - 1, so doing - 5 and + 1 will reset the
      //variable to what it would normally be.
      var = var + 1; //the same here too
    }
  }
  //the same goes for the below code, but with different buttons for
  //multipress, and different actions based on that
  if (v2 == 1) {
    if (v4 == 1) {
      Serial.print(" ");
      v2 = 0;
      v4 = 0;
      var = var + 1;
      var = - 5;
    }
  }
  if (v3 == 1) {
    if (v4 == 1) {
      Serial.println("");
      v3 = 0;
      v4 = 0;
      var = var + 1;
      var = var - 10;
    }
  }
  if (v1 == 1) {
    if (v2 == 1) {
      Serial.print(".");
      v1 = 0;
      v2 = 0;
      var = var - 1;
      var = var - 5;
    }
  }
  //reset the button states.   not sure if i still need these, but dont want to risk deleting them.
  //
  lastButtonState = buttonState;
  lastButtonState1 = buttonState1;
  lastButtonState2 = buttonState2;
  lastButtonState3 = buttonState3;
}