Control a Stepper Motor using an Arduino and a Rotary Encoder - Tutorial - Part 1

n this first part of controlling a Stepper Motor with a Rotary Encoder, we will use the 28BYJ-48 stepper with the included ULN2003 driver board. These little steppers a cheap and good to start learning about using stepper motors with an Arduino.

In Part 2, we will use a Nema 17 motor with the EasyDriver board instead.

here is the code:

#include "Stepper.h"
#define STEPS 32

volatile boolean TurnDetected;
volatile boolean rotationdirection;

const int PinCLK=2;
const int PinDT=3;
const int PinSW=4;

int RotaryPosition=0;

int PrevPosition;
int StepsToTake;

Stepper small_stepper(STEPS, 8, 10, 9, 11);

void isr () {
delay(4);
if (digitalRead(PinCLK))
rotationdirection= digitalRead(PinDT);
else
rotationdirection= !digitalRead(PinDT);
TurnDetected = true;
}

void setup() {

pinMode(PinCLK,INPUT);
pinMode(PinDT,INPUT);
pinMode(PinSW,INPUT);
digitalWrite(PinSW, HIGH);
attachInterrupt (0,isr,FALLING);
}

void loop() {
if(!(digitalRead(PinSW))) {
if(RotaryPosition == 0) {
} else {
RotaryPosition=0;
}
}

if (TurnDetected) {
PrevPosition = RotaryPosition;
if (rotationdirection) {
RotaryPosition=RotaryPosition-1;}
else {
RotaryPosition=RotaryPosition+1;}

TurnDetected = false;

if ((PrevPosition +1) == RotaryPosition) {
StepsToTake=50;
}

if ((RotaryPosition +1) == PrevPosition) {
StepsToTake=-50;
}
}

}

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