Arduino XBee/Wii Receiver

wii_recieve_car.ino

/*  Author: Tim O'Brien
 *  Site: t413.com
 *  Lisence: Creative Commons Attribution-Noncommercial-Share Alike 3.
 *  this file updated: 12/23/09
 *
 *  Let me know if you're using or adapting this,
 *  Leave a comment, send an email, I'd like to hear about it.
 */
#define M1 1
#define M2 0
const int m1pwm = 6, m1c1 = 3, m1c2 = 4;
const int m2pwm = 11, m2c1 = 12, m2c2 = 13;
int dataArray[7];

void setup() {
  Serial.begin(115200);
  pinMode(m1pwm, OUTPUT);
  pinMode(m1c1, OUTPUT);
  pinMode(m1c2, OUTPUT);
  pinMode(m2pwm, OUTPUT);
  pinMode(m2c1, OUTPUT);
  pinMode(m2c2, OUTPUT);
}

void loop(){
  if (Serial.available()>8){
    getcommand();
    //brake
    int inx,iny;
    if (dataArray[1]){   //use accelorometer control
      inx = dataArray[4];
      iny = dataArray[5];
    }  //m_stop(); -- stop
    else {               //use joystick
      inx = dataArray[2];
      iny = dataArray[3];
    }
    int x,y;
    if (inx > 140)
      x =  map( (inx-140) ,0,255-140,0,255);
    else if (inx < 120)
      x = map( (120-inx) ,0,120,0,-255);
    else x = 0;
    // 255/2 = 127.5  129 -- 126
    if (iny > 140)
      y = map( (iny-140) ,0,255-140,0,255);
    else if (iny <= 120)
      y = map( (120-iny),0,120,0,-255);
    else y = 0;

    motor(M1,y-x);
    motor(M2,y+x);

  }
}



void m_stop(){
  digitalWrite(m1c1, LOW);
  digitalWrite(m1c2, LOW);
  digitalWrite(m2c1, LOW);
  digitalWrite(m2c2, LOW);
}

void motor(int which_motor,int this_speed){
  //limiting
  if (this_speed< -255)
    this_speed = -255;
  if (this_speed > 255)
    this_speed = 255;

  if (this_speed > 0){
    if (which_motor == M1){
      digitalWrite(m1c1, HIGH);
      digitalWrite(m1c2, LOW);
      analogWrite(m1pwm, this_speed);
    }
    else {
      digitalWrite(m2c1, HIGH);
      digitalWrite(m2c2, LOW);
      analogWrite(m2pwm, this_speed);
    }
  }
  else { //this_speed < 0
    if (which_motor == M1){
      digitalWrite(m1c1, LOW);
      digitalWrite(m1c2, HIGH);
      analogWrite(m1pwm, -this_speed);
    }
    else {
      digitalWrite(m2c1, LOW);
      digitalWrite(m2c2, HIGH);
      analogWrite(m2pwm, -this_speed);
    }
  }
}


void getcommand(){
  char c = Serial.read();
  char c2 = Serial.read();
  if ((c == 'd')&&(c2 == '=')){
    dataArray[0] = Serial.read();
    dataArray[1] = Serial.read();

    dataArray[2] = Serial.read();
    dataArray[3] = Serial.read();

    dataArray[4] = Serial.read();
    dataArray[5] = Serial.read();
    Serial.read(); //line return
  }
  else {
    while (Serial.read() != '\n'){
    }
  }
}

wii_transmit.ino

/*  Author: Tim O'Brien
 *  Site: t413.com
 *  Lisence: Creative Commons Attribution-Noncommercial-Share Alike 3.
 *  this file updated: 12/23/09
 *
 *  Let me know if you're using or adapting this,
 *  Leave a comment, send an email, I'd like to hear about it.
*/
#include <Wire.h>
uint8_t nunchuck_buf[6];   // array to store nunchuck data,
int i,loop_c=0,reading; 
int ledPin =  13;

void setup(){
  Serial.begin(115200);
  nunchuck_init();
  pinMode(ledPin, OUTPUT);
  //print inital battery charge
  Serial.print("b=");
  Serial.print(update_batt_status());
  Serial.println("%");
}

void loop() {
  nunchuck_get_data();
  if (((nunchuck_buf[5] >> 0) & 1) ? 0 : 1){
    digitalWrite(ledPin, HIGH);
    send_packet();
  } 
  else digitalWrite(ledPin, LOW);
  
  // Print battery state
  if ( Serial.available() > 0) {
    char inchar = Serial.read();
    if ( inchar == 'b') {
      Serial.print("\nb=");
      Serial.print(update_batt_status());
      Serial.println("%");
    }
    else // Print battery voltage
    if ( inchar == 'v') {
      Serial.print("\nv=");
      Serial.print(  (float)analogRead(0)/155  );
      Serial.println("");
    }
    else // poll sensor data.
    if ( inchar == 'd') {
      send_packet();
    }
  }
  if (loop_c++ > 1000*10){
    update_batt_status();
    loop_c = 0;
  }
  delay(1);
}


/* --- my functions --- */

int update_batt_status(){
  //float voltage; 
  int percentage;
  reading = analogRead(0);
  //voltage = (float)reading/155 ;
  percentage = map(reading,465,651,0,100);

  if ((percentage<5)&&(percentage>-50)){
    Serial.print("LOW BATTERY! (");
    Serial.print(percentage);
    Serial.print("%, ");
    Serial.print(reading);
    Serial.print("). Looping.\n");
    while(1){
      digitalWrite(ledPin, HIGH);
      delay(500);
      digitalWrite(ledPin, LOW);
      delay(500);
    }
  }
  return percentage;
}

void send_packet(){
  Serial.print("d=");
  Serial.print( ((nunchuck_buf[5] >> 0) & 1) ? 0 : 1,BYTE);
  Serial.print( ((nunchuck_buf[5] >> 1) & 1) ? 0 : 1,BYTE);

  Serial.print( mapLimit(nunchuck_buf[0], 29, 222),BYTE);
  Serial.print( mapLimit(nunchuck_buf[1], 38, 226),BYTE);

  Serial.print( mapLimit(nunchuck_buf[2], 77, 178),BYTE);
  Serial.print( mapLimit(nunchuck_buf[3], 72, 173),BYTE);
  Serial.println("");
}

int mapLimit(int x,int li,int ui){
  int out = map(x, li, ui, 0,255 );
  if (out<1)
    out = 0;
  if (out>254)
    out = 255;
  return out;
}


/* --- wii functions --- */

/* Code mostly from Robot Overlord,
 *  http://letsmakerobots.com/node/5684
 */

// initialize the I2C system, join the I2C bus,
// and tell the nunchuck we're talking to it
void nunchuck_init() { 
  Wire.begin();                // join i2c bus as master
  Wire.beginTransmission(0x52);// transmit to device 0x52
  Wire.send(0x40);// sends memory address
  Wire.send(0x00);// sends sent a zero.  
  Wire.endTransmission();// stop transmitting
}

// Send a request for data to the nunchuck
// was "send_zero()"
void nunchuck_send_request() {
  Wire.beginTransmission(0x52);// transmit to device 0x52
  Wire.send(0x00);// sends one byte
  Wire.endTransmission();// stop transmitting
}

// Encode data to format that most wiimote drivers except
// only needed if you use one of the regular wiimote drivers
char nunchuk_decode_byte (char x) {
  x = (x ^ 0x17) + 0x17;
  return x;
}

// Receive data back from the nunchuck, 
// returns 1 on successful read. returns 0 on failure
int nunchuck_get_data() {
  int cnt=0;
  Wire.requestFrom (0x52, 6);// request data from nunchuck
  while (Wire.available ()) {
    // receive byte as an integer
    nunchuck_buf[cnt] = nunchuk_decode_byte(Wire.receive());
    cnt++;
  }
  nunchuck_send_request();  // send request for next data payload
  // If we recieved the 6 bytes, then go print them
  if (cnt >= 5) {
    return 1;   // success
  }
  return 0; //failure
}