   Serial.begin(9600);
   pinMode(11,OUTPUT);
   pinMode(13, OUTPUT);
-  inputString.reserve(5);
   Wire.begin(1);
   Wire.onReceive(receiveEvent);
 } 

#include <Wire.h> 
double potcurval;    // variable to read the value from the analog pin 
int angel; //Integer value of angle
 double angle =0;

 double curangle,kP=30.00,kI=0,kD=0,Last=0;
 double P=0,I=0,D=0,Drive,Error=0,Integral=0;
 
 String inputString = "";         // a string to hold incoming data
boolean stringComplete = false;  // whether the string is complete

 void backward()
 {

   
                Error = curangle-angle;
 }
 
 void receiveEvent(int howMany)
  {
    
    if(Wire.available()>0)
    {
  x = Wire.read();
  if(x == 40) 
  digitalWrite(13, HIGH);
  else digitalWrite(13, LOW);
 angle = (double) x;
    }  
}

 
 
void loop() 
{               
   
                 Errorcalc();
                if (abs(Error) <2.2){ // prevent integral 'windup'
                Integral = Integral + Error; // accumulate the error integral
