Simple RC Car Programming Issue

Other Hardware Sensors
5

I fixed up your code from any errors and made it simpler to understand:

int ir_pin = 2;		//Sensor pin 1 wired through a 220 ohm resistor		
int led_pin = 13;        // built in LED

int ledLEFT = 12;
int ledFORWARD = 11;
int ledBACK = 10;
int ledRIGHT = 8;
				
int debug = 1;				  
int start_bit = 2000;			
int bin_1 = 1000;				
int bin_0 = 400;				   


void setup() {
 pinMode(led_pin, OUTPUT);		
 pinMode(ir_pin, INPUT);
 
 pinMode(ledLEFT, OUTPUT);
 pinMode(ledFORWARD, OUTPUT);
 pinMode(ledBACK, OUTPUT);
 pinMode(ledRIGHT, OUTPUT);
 
 digitalWrite(led_pin, LOW);	
 
 Serial.begin(9600);
}

void loop()
{
   int key = getIRKey();
   if (key != -1)
   {
     Serial.print("Key Received: ");
     Serial.println(key);
   }
   
   switch (key)
   {
     case 16:                      // left + forward
       LF();
       break;
       
     //case xxxx:                    // forward
     //  f();
     //  break;
       
     case 1040:                    // right + forward
       RF();
       break;
       
     case 2064:                    // left + back
       LB();
       break;
       
     case 528:                     // back
       B();
       break;
       
     //case xxxx:                    // right + back
       RB();
       break;
       
     //case xxxx:                    // stop
     //  S();
     //  break;
       
     case -1:                      // no key received
       break;
   }
}
 
  void LF()                          //To go left + forward.
  {                           
    digitalWrite(ledLEFT, HIGH);
    digitalWrite(ledFORWARD, HIGH);
    digitalWrite(ledBACK, LOW);
    digitalWrite(ledRIGHT, LOW);
    delay(100);
    digitalWrite(ledFORWARD, LOW);
  }
  
  void f()                     //To go forward.      
  {
     digitalWrite(ledLEFT, LOW);
     digitalWrite(ledFORWARD, HIGH); 
     digitalWrite(ledBACK, LOW);
     digitalWrite(ledRIGHT, LOW);
     delay(100);
     digitalWrite(ledFORWARD, LOW);
  }
  
  void RF()                      //To go right + forward.
  {
     digitalWrite(ledLEFT, LOW);
     digitalWrite(ledFORWARD, HIGH);
     digitalWrite(ledBACK, LOW); 
     digitalWrite(ledRIGHT, HIGH);
     delay(100);
     digitalWrite(ledFORWARD, LOW);
  }
  
  void LB() {                         //To go left + back.                         
    digitalWrite(ledLEFT, HIGH);
    digitalWrite(ledFORWARD, LOW); 
    digitalWrite(ledBACK, HIGH);
    digitalWrite(ledRIGHT, LOW);
    delay(100);
    digitalWrite(ledBACK, LOW);
  }
  
  void B() {                          //To go back. 
    digitalWrite(ledLEFT, LOW);
    digitalWrite(ledFORWARD, LOW); 
    digitalWrite(ledBACK, HIGH);
    digitalWrite(ledRIGHT, LOW);
    delay(100);
    digitalWrite(ledBACK, LOW);
  }
  
  void RB() {                         //To go right + back. 
    digitalWrite(ledLEFT, LOW);
    digitalWrite(ledFORWARD, LOW); 
    digitalWrite(ledBACK, HIGH);
    digitalWrite(ledRIGHT, HIGH);
    delay(100);
    digitalWrite(ledBACK, LOW);
  }
  
  void S() {                         //To stop. 
    digitalWrite(ledLEFT, LOW);
    digitalWrite(ledFORWARD, LOW); 
    digitalWrite(ledBACK, LOW);
    digitalWrite(ledRIGHT, LOW);
    delay(100);
  }


int getIRKey() {
  int data[12];
  
  digitalWrite(led_pin, HIGH);     
  while(pulseIn(ir_pin, LOW) < 2200) {
  }
 
 data[0] = pulseIn(ir_pin, LOW);	 
 data[1] = pulseIn(ir_pin, LOW);
 data[2] = pulseIn(ir_pin, LOW);
 data[3] = pulseIn(ir_pin, LOW);
 data[4] = pulseIn(ir_pin, LOW);
 data[5] = pulseIn(ir_pin, LOW);
 data[6] = pulseIn(ir_pin, LOW);
 data[7] = pulseIn(ir_pin, LOW);
 data[8] = pulseIn(ir_pin, LOW);
 data[9] = pulseIn(ir_pin, LOW);
 data[10] = pulseIn(ir_pin, LOW);
 data[11] = pulseIn(ir_pin, LOW);
 
 digitalWrite(led_pin, LOW);

 if (debug == 1) {
 }
 
 for (int i=0; i<=11; i++) {		    
   if (debug == 1) {  
   }
   
   if(data[i] > bin_1) {		    
	 data[i] = 1;
        }
   else {
	 if(data[i] > bin_0) {	     
	   data[i] = 0; }
         else {
	   data[i] = 2;			  
	 }
   }
 }

 for (int i = 0; i <= 11; i++)
 {		     
   if (data[i] > 1)
   {
     return -1;				
   }
 }

 int result = 0;
 int seed = 1;
 for(int i = 11; i >= 0; i--)
 {		  
   if(data[i] == 1)
   {
     result += seed;
   }
   seed = seed * 2;
 } 
 return result;
}