Our Goals for the SmartChair

User Exp
Approaching moving or stationery objects but doesn’t say if its moving because it doesn’t matter
Warns user to prevent from going out into the street
Warns distance of the curb from the current location of the User
Tells the distance of the building from the User
Wheel-alignment sensor
User input(a button that will potentially tell the User which direction they are going)

Side Goals:
Tells the user which side the curb would be
Tell the user how long they have before they hit the object or curb

We also finished the code and recordings for the user portion of the project, we ran into a little trouble with the circuit working, we think it could be because we used a SDHC card instead of a SD card, tomorrow we are going to test it with a regular SD card, if it is the circuit itself, Joe will be our savior and make a second working circuit!

Here is the code that Joe worked on

#include “WaveUtil.h”
#include “WaveHC.h”

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

#define DEBOUNCE 5 // button debouncer

// here is where we define the buttons that we’ll use. button “1” is the first, button “6” is the 6th, etc
byte buttons[] = {
// This handy macro lets us determine how big the array up above is, by checking the size
#define NUMBUTTONS sizeof(buttons)
// we will track if a button is just pressed, just released, or ‘pressed’ (the current state
volatile byte pressed[NUMBUTTONS], justpressed[NUMBUTTONS], justreleased[NUMBUTTONS];

int currTrack = 0;

// 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 free_memory;
if((int)__brkval == 0) {
free_memory = ((int)&free_memory) – ((int)&__bss_end);
else {
free_memory = ((int)&free_memory) – ((int)__brkval);
return free_memory;

void sdErrorCheck(void)
if (!card.errorCode()) return;
putstring(“\n\rSD I/O error: “);
Serial.print(card.errorCode(), HEX);
putstring(“, “);
Serial.println(card.errorData(), HEX);

void setup() {
byte i;

// set up serial port
putstring_nl(“WaveHC with “);
Serial.print(NUMBUTTONS, DEC);

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);

// Make input & enable pull-up resistors on switch pins
for (i=0; i< NUMBUTTONS; i++) {
pinMode(buttons[i], INPUT);
digitalWrite(buttons[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
while(1); // then 'halt' – do nothing!

// enable optimize read – some cards may timeout. Disable if you're having problems

// 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!

// Lets tell the user about what we found
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.

TCCR2A = 0;
TCCR2B = 1<<CS22 | 1<<CS21 | 1<<CS20;

//Timer2 Overflow Interrupt Enable
TIMSK2 |= 1<<TOIE2;



void check_switches()
static byte previousstate[NUMBUTTONS];
static byte currentstate[NUMBUTTONS];
byte index;

for (index = 0; index 10){
currTrack = 0;

// Plays a full file from beginning to end with no pause.
void playcomplete(char *name) {
// call our helper to find and play this 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 “);
// OK read the file and turn it into a wave object
if (!wave.create(f)) {
putstring_nl(“Not a valid WAV”);

// ok time to play! start playback

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