byter middle

#include <SoftwareSerial.h>

SoftwareSerial bt(2,3); // rx, tx

int sp = 255;

#define pwma 5
#define pwmb 9

#define ain2 4 // Right motor AO1 +
#define ain1 6 // Right motor AO2 -
#define bin1 7 // Left motor BO1 +
#define bin2 8 // Left motor BO2 -

void setup() {
  pinMode(pwma, OUTPUT);
  pinMode(pwmb, OUTPUT);
  pinMode(ain2, OUTPUT);
  pinMode(ain1, OUTPUT);
  pinMode(bin1, OUTPUT);
  pinMode(bin2, OUTPUT);

  analogWrite(pwma, sp);
  analogWrite(pwmb, sp);

  bt.begin(9600);
  Serial.begin(9600);
}
void loop () {
  if (bt.available() > LOW) {

    char cmd = bt.read();
    Serial.println(cmd);
    switch (cmd) {
      case 'F':
        forward();
        break;
      case 'B':
        backward();
        break;
      case 'L':
        left();
        break;
      case 'R':
        right();
        break;
      case 'G':
        forwardLeft();
        break;
      case 'I':
        forwardRight();
        break;
      case 'H':
        backwardLeft();
        break;
      case 'J':
        backwardRight();
        break;
      case '0':
      case '1':
      case '2':
      case '3':
      case '4':
      case '5':
      case '6':
      case '7':
      case '8':
      case '9':
      case 'q':
        speedByter(cmd);
        break;
      default:
        stopByter();
        break;
    }
  }
}

void speedByter(char s) {
  if (s != 'q') {
    int ss = (int)s;
    sp = 255 / 100 * ss;

  } else {
    sp = 255;
  }
  analogWrite(pwma, sp);
  analogWrite(pwmb, sp);
}

void stopByter() {
  analogWrite(pwma, sp);
  analogWrite(pwmb, sp);

  digitalWrite(ain2, LOW);
  digitalWrite(ain1, LOW);
  digitalWrite(bin1, LOW);
  digitalWrite(bin2, LOW);
}
void forward() {
  analogWrite(pwma, sp);
  analogWrite(pwmb, sp);

  digitalWrite(ain2, HIGH);
  digitalWrite(ain1, LOW);
  digitalWrite(bin1, LOW);
  digitalWrite(bin2, HIGH);
}
void backward() {
  analogWrite(pwma, sp);
  analogWrite(pwmb, sp);

  digitalWrite(ain2, LOW);
  digitalWrite(ain1, HIGH);
  digitalWrite(bin1, HIGH);
  digitalWrite(bin2, LOW);
}
void left() {
  analogWrite(pwma, sp);
  analogWrite(pwmb, sp);

  digitalWrite(ain2, LOW);
  digitalWrite(ain1, HIGH);
  digitalWrite(bin1, LOW);
  digitalWrite(bin2, HIGH);
}
void right() {
  analogWrite(pwma, sp);
  analogWrite(pwmb, sp);

  digitalWrite(ain2, HIGH);
  digitalWrite(ain1, LOW);
  digitalWrite(bin1, HIGH);
  digitalWrite(bin2, LOW);
}

void forwardLeft() {
  analogWrite(pwma, sp / 3);

  digitalWrite(ain2, HIGH);
  digitalWrite(ain1, LOW);
  digitalWrite(bin1, LOW);
  digitalWrite(bin2, HIGH);
}

void forwardRight() {
  analogWrite(pwmb, sp / 3);

  digitalWrite(ain2, HIGH);
  digitalWrite(ain1, LOW);
  digitalWrite(bin1, LOW);
  digitalWrite(bin2, HIGH);
}

void backwardLeft() {
  analogWrite(pwmb, sp / 3);

  digitalWrite(ain2, LOW);
  digitalWrite(ain1, HIGH);
  digitalWrite(bin1, HIGH);
  digitalWrite(bin2, LOW);
}

void backwardRight() {
  analogWrite(pwma, sp / 3);

  digitalWrite(ain2, LOW);
  digitalWrite(ain1, HIGH);
  digitalWrite(bin1, HIGH);
  digitalWrite(bin2, LOW);
}