// Control character
String mm = ""; // move  
// Control pins
int f_sp = 32; // front speed 
int f_st = 33; // front steering 
int b_sp = 25; // back speed 
int b_st = 26; // back steering 
// back pin for relay  >>> encoder
int rel_back = 24; // 

void setup() {
  // put your setup code here, to run once:
  pinMode(f_sp, OUTPUT); 
  pinMode(f_st, OUTPUT);
  pinMode(b_sp, OUTPUT);
  pinMode(b_st, OUTPUT);
  pinMode(rel_back, OUTPUT);

  // serial 
  Serial.begin(9600);
}

void loop() {
  // put your main code here, to run repeatedly:
  if (Serial.available()){
    mm = Serial.readStringUntil('\n');
    move(mm);
  }
  // forward("f5");
}

void move(String m) {
  // steering in middle
  int f_middle = 128; 
  int b_middle = 128;
  // speed
  int first_speed = 140;
  int sec_speed = 168; 
  int third_speed = 196; 
  int fourth_speed = 224; 
  int fifth_speed = 255; 
  int stop_value =130 ;  
  
  if (m == "f1") { // lowest speed 
    Serial.println("first"); 
    // steering  // only one time >>>  and it never change 
    analogWrite(f_st, f_middle); 
    analogWrite(b_st, f_middle);
    // speed 
    analogWrite(f_sp, first_speed); 
    analogWrite(b_sp, first_speed); 
    digitalWrite(rel_back, LOW);// TO REMOVE BACK 

  } else if (m == "f2"){
    Serial.println("second"); 
    // speed 
    analogWrite(f_sp, sec_speed); 
    analogWrite(b_sp, sec_speed); 
  } else if (m == "f3"){
    Serial.println("third"); 
    // speed 
    analogWrite(f_sp, third_speed); 
    analogWrite(b_sp, third_speed); 
  } else if (m == "f4"){
    Serial.println("fourth"); 
    // speed 
    analogWrite(f_sp, fourth_speed); 
    analogWrite(b_sp, fourth_speed); 
  } else if (m == "f5"){
    Serial.println("fifth"); 
    // speed 
    analogWrite(f_sp, fifth_speed); 
    analogWrite(b_sp, fifth_speed); 
  }
  // stop 
  else if (m=="st"){
    // steering  // only one time >>>  and it never change 
    analogWrite(f_st, f_middle); 
    analogWrite(b_st, f_middle);
    // speed 
    analogWrite(f_sp, first_speed - 10 ); 
    analogWrite(b_sp, first_speed - 10 ); 
  }
  // turnnig right 
  else if (m=="tr"){
    // steering  // max to reach to  be right 
    analogWrite(f_st, 255); 
    analogWrite(b_st, 255);
    // speed 
    analogWrite(f_sp, first_speed); 
    analogWrite(b_sp, first_speed); 
    digitalWrite(rel_back, LOW);// TO REMOVE BACK 
  }
  // turnnig left 
  else if (m=="tl"){
    // steering  // max to reach to  be right 
    analogWrite(f_st, 255); 
    analogWrite(b_st, 255);
    // speed 
    analogWrite(f_sp, first_speed); 
    analogWrite(b_sp, first_speed); 
    digitalWrite(rel_back, LOW);// TO REMOVE BACK 
  }
}