Arduino Code for Image Processing Robot

cv_robot.ino

int pin_e1 = 52;
int pin_in1_1 = 50;
int pin_in1_2 = 48;

int pin_e2 = 42;
int pin_in2_1 = 40;
int pin_in2_2 = 38;

void full_right()
{
  digitalWrite(pin_in1_1, HIGH);
  digitalWrite(pin_in1_2, LOW);
  digitalWrite(pin_in2_1, HIGH);
  digitalWrite(pin_in2_2, LOW);
}

void full_left()
{
  digitalWrite(pin_in1_1, LOW);
  digitalWrite(pin_in1_2, HIGH);
  digitalWrite(pin_in2_1, LOW);
  digitalWrite(pin_in2_2, HIGH);
}

void backward()
{
  digitalWrite(pin_in1_1, LOW);
  digitalWrite(pin_in1_2, HIGH);
  digitalWrite(pin_in2_1, HIGH);
  digitalWrite(pin_in2_2, LOW);
}

void forward()
{
  digitalWrite(pin_in1_1, HIGH);
  digitalWrite(pin_in1_2, LOW);
  digitalWrite(pin_in2_1, LOW);
  digitalWrite(pin_in2_2, HIGH);
}

void left()
{
  digitalWrite(pin_in1_1, HIGH);
  digitalWrite(pin_in1_2, LOW);
  digitalWrite(pin_in2_1, LOW);
  digitalWrite(pin_in2_2, LOW);
}

void right()
{
  digitalWrite(pin_in1_1, LOW);
  digitalWrite(pin_in1_2, LOW);
  digitalWrite(pin_in2_1, HIGH);
  digitalWrite(pin_in2_2, LOW);
}

void stall()
{
  digitalWrite(pin_in1_1, LOW);
  digitalWrite(pin_in1_2, LOW);
  digitalWrite(pin_in2_1, LOW);
  digitalWrite(pin_in2_2, LOW);
}

void freerun()
{
    digitalWrite(pin_e1,LOW);
    digitalWrite(pin_e2,LOW);
}

void callfunc(int x)
{
  if(x==119) forward();		//if 'w' is sent
  if(x==115) backward();	//if 's' is sent
  if(x==97) full_left();	//if 'a' is sent
  if(x==100) full_right();	//if 'd' is sent
}

void setup()
{
  Serial.begin(9600);
  pinMode(pin_e1, OUTPUT);
  pinMode(pin_in1_1, OUTPUT);
  pinMode(pin_in1_2, OUTPUT);
  digitalWrite(pin_e1, HIGH);
  pinMode(pin_e2, OUTPUT);
  pinMode(pin_in2_1, OUTPUT);
  pinMode(pin_in2_2, OUTPUT);
  digitalWrite(pin_e2, HIGH);
  pinMode(22,OUTPUT);
  pinMode(24,OUTPUT);
  
}

void loop()
{ 
  if(Serial.available())
  {
    callfunc(Serial.read());
    delay(50);
    stall();
  }
}