I started work tonight on making the joystick on Molly’s Bar do something.

I used the adafruit Wave Shield to make an arduino play sounds when buttons are pressed.

Here’s the arduino sourcecode:

/*
  MollyBar
  Controls the lighting, music and breathalyzer on Molly's Bar according to the joystick input
*/

#include <FatReader.h>
#include <SdReader.h>
#include <avr/pgmspace.h>
#include "WaveUtil.h"
#include "WaveHC.h"

// The density of output to Serial is determined by the value of this constant
#define DEBUG 0

// Action queue
#define QUEUESIZE 16
volatile int QueueStart = 0;
volatile int QueueEnd = 0;
volatile int QueueSize = 0;
volatile int Queue[QUEUESIZE];

// Buttons
#define BUTTONZERO 6
#define NBUTTONS 6
#define NSOUNDBUTTONS 2
#define DEBOUNCE 100  // button debouncer; don't press the buttons too quickly

// Sound files
char* SoundFileNames[] = { "Shots.wav", "LineEmUp.wav" };

// Wave Shield variables
SdReader card;    // This object holds the information for the card
FatVolume vol;    // This holds the information for the partition on the card
FatReader root;   // This holds the information for the filesystem on the card
FatReader f;      // This holds the information for the file we're play
WaveHC wave;      // This is the only wave (audio) object, since we will only play one at a time

// this handy function will return the number of bytes currently free in RAM, great for debugging!
int freeRam(void) {
  extern int  __bss_end;
  extern int  *__brkval;
  int freememory;
  if((int)__brkval == 0) {
    freememory = ( (int)&freememory ) - ( (int)&__bss_end );
  }
  else {
    freememory = ( (int)&freememory ) - ( (int)__brkval );
  }
  return freememory;
}

// Check for an error with the SD card
void SDErrorCheck(void) {
  if ( !card.errorCode() ) return;
  putstring("\n\rSD I/O error: ");
  Serial.print( card.errorCode(), HEX );
  putstring(", ");
  Serial.println( card.errorData(), HEX );
  while(1);
}

// Setup
void setup() {
  // Set up serial port
  Serial.begin(9600);
  Debug( "Molly's Bar Joystick!", true );

  if (DEBUG) {
    putstring("Free RAM: ");       // This can help with debugging, running out of RAM is bad
    Serial.println(freeRam());      // if this is under 150 bytes it may spell trouble!
  }

  // Set the output pins for the DAC control. This pins are defined in the library
  pinMode( 2, OUTPUT );
  pinMode( 3, OUTPUT );
  pinMode( 4, OUTPUT );
  pinMode( 5, OUTPUT );

  // pin13 LED
  pinMode( 13, OUTPUT );

  // Enable joystick buttons
  for ( byte i = 0; i < NBUTTONS; i++ ) {
    pinMode( BUTTONZERO + i, INPUT );
    digitalWrite( BUTTONZERO + i, HIGH );
  }

  //  if (!card.init(true)) { //play with 4 MHz spi if 8MHz isn't working for you
  if ( !card.init() ) {         //play with 8 MHz spi (default faster!)
    putstring_nl("Card init. failed!");  // Something went wrong, lets print out why
    SDErrorCheck();
    while(1);                            // then 'halt' - do nothing!
  }

  // enable optimize read - some cards may timeout. Disable if you're having problems
  card.partialBlockRead(true);

// Now we will look for a FAT partition!
  uint8_t part;
  for ( part = 0; part < 5; part++ ) {     // we have up to 5 slots to look in
    if ( vol.init(card, part) )
      break;                             // we found one, lets bail
  }
  if ( part == 5 ) {                       // if we ended up not finding one  
    putstring_nl("No valid FAT partition!");
    SDErrorCheck();      // Something went wrong, lets print out why
    while(1);                            // then 'halt' - do nothing!
  }

  // Tell the user about what we found
  if (DEBUG) {
    putstring("Using partition ");
    Serial.print(part, DEC);
    putstring(", type is FAT");
    Serial.println(vol.fatType(),DEC);     // FAT16 or FAT32?
  }

  // Try to open the root directory
  if ( !root.openRoot(vol) ) {
    putstring_nl("Can't open root dir!"); // Something went wrong,
    while(1);                             // then 'halt' - do nothing!
  }

  // Whew! We got past the tough parts.
  Debug( "Ready!", true );
}

// The main execution loop
void loop() {
  // Enqueue any new button press
  int buttonpressed = ButtonPressed();
  if ( buttonpressed >= 0 ) {
    if ( buttonpressed < NSOUNDBUTTONS ) {
      if( Enqueue(buttonpressed) ) {
        Debug( "Enqueued \"", false );
        Debug( SoundFileNames[buttonpressed], false);
        Debug( "\"", true );
      }
      else {
        Debug( "Enqueue failed: queue is full.", true );
      }
    }
    else if (DEBUG) {
      putstring("No action associated with button ");
      Serial.println( buttonpressed, DEC );
    }
  }

  // Dequeue an existing action
  int action = Dequeue();
  if ( action >= 0 ) {
    Debug( "Dequeue \"", false );
    Debug( SoundFileNames[action], false );
    Debug( "\"", true );
    PlayFile(SoundFileNames[action]);
  }
}

// Output to Serial if the DEBUG flag is on
void Debug(char *message, boolean newline) {
  if (DEBUG) {
    Serial.print(message);
    if (newline) {
      Serial.println();
    }
  }
}

// Check to see if a button was pressed
int ButtonPressed() {
  static byte previous[NBUTTONS];
  static long time[NBUTTONS];
  byte reading;
  int pressed;
  byte index;
  pressed = -1;

  for ( byte i = 0; i < NBUTTONS; i++ ) {
    reading = digitalRead( BUTTONZERO + i );
    if ( reading == LOW && previous[i] == HIGH && millis() - time[i] > DEBOUNCE ) {
      // Button pressed
      time[i] = millis();
      pressed = i;
      break;
    }
    previous[i] = reading;
  }

  // return button number (0 - 5)
  return pressed;
}

// Enqueue an action
boolean Enqueue(int action) {
  if ( QueueSize < QUEUESIZE ) {
    QueueSize++;
    Queue[QueueEnd] = action;
    QueueEnd = ( QueueEnd + 1 ) % QUEUESIZE;
    return true;
  }
  return false;
}

// Dequeue an action
int Dequeue() {
  int action;
  if ( QueueSize > 0 ) {
    action = Queue[QueueStart];
    QueueStart = ( QueueStart + 1 ) % QUEUESIZE;
    QueueSize--;
  }
  else {
    action = -1;
  }
 return action;
}

// Plays a full file from beginning to end with no pause.
void PlayComplete(char *name) {
  // call our helper to find and play this name
  PlayFile(name);
  while (wave.isplaying) {
  // do nothing while its playing
  }
  // now its done playing
}

void PlayFile(char *name) {
  // see if the wave object is currently doing something
  if (wave.isplaying) {// already playing something, so stop it!
    wave.stop(); // stop it
  }
  // look in the root directory and open the file
  if (!f.open(root, name)) {
    putstring("Couldn't open file "); Serial.print(name); return;
  }
  // OK read the file and turn it into a wave object
  if (!wave.create(f)) {
    putstring_nl("Not a valid WAV"); return;
  }

  // ok time to play! start playback
  wave.play();
}

And here’s some video of the thing in action:
20110718-200559.mov