Stepper Rotary Encoder

//Copyright Evan Johnson, 2015

//GPL 3.0 license. Feel free to redistribute

//Please cite me in your project. 

//Email me for questions:  erjohnson227@gmail.com

  

#include <AFMotor.h>  

#include <AccelStepper.h>  

  

// Connect a stepper motor with 48 steps per revolution (7.5 degree)  

// to motor port #2 (M3 and M4)  

  

int clockPin = 10;   

int inPin    = 11;   

int CSPin    = 12;   

  

uint16_t count = 0;   

uint16_t data = 0;   

uint16_t posLast = 0;   

int16_t revs = 0;   

uint16_t contPos = 0;   

  

  

AF_Stepper motor(100, 2);  

  

void stepForward2()  

{  

  motor.onestep(FORWARD, SINGLE);   

}  

void stepBackward2()  

{  

  motor.onestep(BACKWARD, SINGLE);   

}  

  

AccelStepper stepper2(stepForward2, stepBackward2);   

  

  

  

void setup() {  

  Serial.begin(9600);           // set up Serial library at 9600 bps  

  Serial.println("Stepper test!");  

    

  pinMode(CSPin, OUTPUT);   

  pinMode(clockPin, OUTPUT);   

    

  digitalWrite(clockPin, LOW);   

  digitalWrite(CSPin, HIGH);   

  

  motor.setSpeed(10);  // 10 rpm    

  stepper2.setMaxSpeed(600.0);   

  stepper2.setAcceleration(10000.0);    

  stepper2.setCurrentPosition(0.0);   

  stepper2.moveTo(0);   

}  

  

void loop() {  

    

   if((count % 500) == 0)  

   {  

    digitalWrite(CSPin, LOW);   

    //delayMicroseconds(10);   

    uint8_t dataHigh = shiftIn(inPin, clockPin, MSBFIRST);   

    uint8_t dataLow = shiftIn(inPin, clockPin, MSBFIRST);   

    digitalWrite(CSPin, HIGH);   

      

    data = (dataHigh << 8) | dataLow; //Bring 16 bit data into one byte.   

    

    uint16_t pos = data >> 6;   

      

    int delPos = pos - posLast;   

      

    if(delPos < 0)  

      delPos = - delPos;   

        

    if((posLast >= 900) && (pos <= 100))  

      revs ++;   

    else if((pos >= 900) && (posLast <= 100))  

      revs --;   

        

      

    if(delPos > 0)  

    {  

      stepper2.moveTo((float)(pos+revs*1024.0f)*(200.0f/1024.0f));   

      //Serial.print(revs, DEC);   

      //Serial.print(", ");   

      //Serial.println(pos, DEC);   

    }  

      

    posLast = pos;   

       

   }  

     

    count ++;    

      

   stepper2.run();  

     

}