BattleBot

const int in1 = 9;
const int in2 = 8;
const int in3 = 7;
const int in4 = 6;
const int ENA = 10;
const int ENB = 5;
char j;
const int speed = 0;

void setup()
{
  pinMode(in1, OUTPUT);
  pinMode(in2, OUTPUT);
  pinMode(ENA, OUTPUT);
  pinMode(in3, OUTPUT);
  pinMode(in4, OUTPUT);
  pinMode(ENB, OUTPUT);

  Serial.begin(9600);
}

void loop()
{
  if(Serial.available())
  {
    j = Serial.read();
  }
  analogWrite(ENA, speed);
  analogWrite(ENB, speed);

  if(j == 'U')
  {
    forward();
  }
  if(j == 'D')
  {
    backward();
  }
  if(j == 'S')
  {
    stop();
  }
  if(j == 'L')
  {
    left();
  }
  if(j == 'R')
  {
    right();
  }
  if(j == 'F')
  {
    speed = 255;
  }
  if(j == 'M')
  {
    speed = 155;
  }



}

void forward()
{
  digitalWrite(in1, HIGH);
  digitalWrite(in2, LOW);
  digitalWrite(in3, HIGH);
  digitalWrite(in4, LOW);
}
void backward()
{
  digitalWrite(in1, LOW);
  digitalWrite(in2, HIGH);
  digitalWrite(in3, LOW);
  digitalWrite(in4, HIGH);
}
void left()
{
  digitalWrite(in1, LOW);
  digitalWrite(in2, LOW);
  digitalWrite(in3, HIGH);
  digitalWrite(in4, LOW);
}
void right()
{
  digitalWrite(in1, HIGH);
  digitalWrite(in2, LOW);
  digitalWrite(in3, LOW);
  digitalWrite(in4, LOW);
}
void stop()
{
  digitalWrite(in1, LOW);
  digitalWrite(in2, LOW);
  digitalWrite(in3, LOW);
  digitalWrite(in4, LOW);
}