4wd robot arduino bluetooth control

4wd_robot_arduino_bluetooth

int enableA = 1;
int pinA1 = 3;
int pinA2 = 2;

int enableB = 6;
int pinB1 = 5;
int pinB2 = 4;

char state = '0';

void setup() {
  //configure pin modes for the drive motors
  pinMode (enableA, OUTPUT);
  pinMode (pinA1, OUTPUT);
  pinMode (pinA2, OUTPUT);
  
  pinMode (enableB, OUTPUT);
  pinMode (pinB1, OUTPUT);
  pinMode (pinB2, OUTPUT); 
  
  Serial.begin(9600); // Default connection rate for my BT module
}

void loop() {
  state = Serial.read();  

  if (state == 'f') {
    forward(10);
  }
  else if (state == 'b') {
    backward(10);
  }
  else if (state == 'l') {
    left(10);
  }
  else if (state == 'r') {
    right(10);
  }   
  else if (state == 's') {
    breakRobot(10);
  }  
  else if (state == '1') {
    enableMotors();
  }   
  else if (state == '0') {
    disableMotors();
  } 
     
}

//motor functions
void motorAforward() {
  digitalWrite (pinA1, HIGH);
  digitalWrite (pinA2, LOW);
}
void motorBforward() {
  digitalWrite (pinB1, LOW);
  digitalWrite (pinB2, HIGH);
}
void motorAbackward() {
  digitalWrite (pinA1, LOW);
  digitalWrite (pinA2, HIGH);
}
void motorBbackward() {
  digitalWrite (pinB1, HIGH);
  digitalWrite (pinB2, LOW);
}
void motorAstop() {
  digitalWrite (pinA1, HIGH);
  digitalWrite (pinA2, HIGH);
}
void motorBstop() {
  digitalWrite (pinB1, HIGH);
  digitalWrite (pinB2, HIGH);
}
void motorAon() {
  digitalWrite (enableA, HIGH);
}
void motorBon() {
  digitalWrite (enableB, HIGH);
}
void motorAoff() {
  digitalWrite (enableA, LOW);
}
void motorBoff() {
  digitalWrite (enableB, LOW);
}

// Movement functions
void forward(int duration) {
  motorAforward();
  motorBforward();
  delay (duration);
}
void backward(int duration) {
  motorAbackward();
  motorBbackward();
  delay (duration);
}
void right(int duration) {
  motorAbackward();
  motorBforward();
  delay (duration);
}
void left(int duration) {
  motorAforward();
  motorBbackward();
  delay (duration);
}
void breakRobot(int duration) {
  motorAstop();
  motorBstop();
  delay (duration);
}
void disableMotors() {
  motorAoff();
  motorBoff();
}
void enableMotors() {
  motorAon();
  motorBon();
}