//// Example 8, Master, Tansmitter, one encoder controls one stepper motor
//#define outputA 6
//#define outputB 7
//#include<Wire.h>
//
//int8_t counter = 0; 
//int aState;
//int aLastState;  
//int8_t stepper_1_pos[30]={};
//int i;
//void setup() {
//   Serial.begin(9600);
//   Wire.begin();
//   pinMode (outputA,INPUT);
//   pinMode (outputB,INPUT);
//   aLastState = digitalRead(outputA);   
//   i=0;
//}
//void loop(){
//   aState = digitalRead(outputA); // Reads the "current" state of the outputA
//   // If the previous and the current state of the outputA are different, that means a Pulse has occured
//   if (aState != aLastState){     
//     // If the outputB state is different to the outputA state, that means the encoder is rotating clockwise
//     if (digitalRead(outputB) != aState) { 
//       counter ++;
//     } 
//     else {
//       counter --;
//     }
//     stepper_1_pos[i]=counter;
//     Wire.beginTransmission(9);// send through I2C to slave, 9 here is the address of the slave board 
//     Wire.write(stepper_1_pos[i]);//Transfers the value of potentiometer to the slave board            
//     Wire.endTransmission();  
//     i++;
//   } 
//   aLastState = aState; // Updates the previous state of the outputA with the current state 
//}

//// Slave, receiver, which controls the motor
//#include<Wire.h>
//#include <Stepper.h>
//#define pushbutton 2
//int buttonState, buttonStateLast;
//const int stepsPerRevolution = 2038; // the number of steps in one revolution of your motor (28BYJ-48)
//// initialize the stepper library on pins 8 through 11:
//Stepper myStepper_1(stepsPerRevolution, 13, 11, 12, 10); // 8, 10, 9, 11
//int8_t stepper_1_pos_rec[100]={};//they need to be 8-bit signed numbers. byte is unsigned, int is 16-bit. 
//int8_t stepSize[100]={};
//int i, j, m, n, k;
//
//void setup() {
//    pinMode(pushbutton,INPUT);//detect the pushbutton triggering to send the data to the motor
//    myStepper_1.setSpeed(5); // 5 rpm
//    Wire.begin(9);// matching the address defined in the master. 
//    Wire.onReceive(receiveEvent);// whenever receives anything will trigger the receiveEvent() function
//    Serial.begin(9600);
//    i=0;
//    buttonState=0;
//    buttonStateLast=0;
//}
//void receiveEvent(int8_t bytes){
//    stepper_1_pos_rec[i]=Wire.read();
//    Serial.println(stepper_1_pos_rec[i]);    
//    i++;
//}
//void loop(){
//  buttonState=digitalRead(pushbutton);
//  if (buttonState != buttonStateLast && buttonState ==HIGH){
//    for(m=0;m<i-1;m++){
//      stepSize[m]=stepper_1_pos_rec[m+1]-stepper_1_pos_rec[m];
//    }
//    moveStepper_1();
//  }
//  buttonStateLast=buttonState;
//}
//void moveStepper_1(){
//  for (n=0;n<m;n++){
//     myStepper_1.step(stepSize[n]*50);          
//  }
//  for (j=0;j<m;j++){
//    stepSize[j]=0;
//  }
//  for (k=0;k<i;k++){
//    stepper_1_pos_rec[k]=0;
//  }
//}