// https://forum.arduino.cc/t/an-arduino-to-control-and-count-to-200-rev-for-a-coil-winder/1323683

/*
  - The wire is attached to one side of the bobbin.
  - The bobbin is attached to the stepper motor spindle.
  - A pulley is suspended on a rod above the bobbin.
  - The motor rotates, turning the bobbin, taking up the wire.
  - The servo arm pulls and pushes the pulley along the rod.
  - The stepper motor has 200 steps per revolution
  - Stepping every 0.5 ms makes about 1000 steps (5 revolutions) per second
*/

#include <Stepper.h>
#include <Servo.h>

const byte stepsPerRevolution = 200;
const byte dirPin = 2, stepPin = 3;
bool stepState = 0;

Servo servo;
const byte servoPin = 4;
const int servoHome = 90, servoSweep = 10;
const int servoLeft = servoHome - servoSweep,  servoRight = servoHome + servoSweep;
int servoDir = 1; // - (left) or + (right)
int servoAngle = servoLeft;
int steps;

unsigned long timer, timeout = 500; // microseconds

void setup() {
  Serial.begin(11520);
  pinMode(stepPin, OUTPUT);
  pinMode(dirPin, OUTPUT);
  digitalWrite(dirPin, HIGH);

  servo.attach(servoPin);
  servo.write(servoLeft);
}

void loop() {
  if (micros() - timer > timeout) { // wait for next step
    timer = micros(); // reset timer
    step(); // move motor
    if (steps++ > stepsPerRevolution) { // count to one revolution
      steps = 0;
      sweep(); // move servo every revolution
    }
  }
}

void sweep() {
  if (servoAngle < servoLeft || servoAngle > servoRight) // check servo boundaries
    servoDir = -servoDir; // change servo direction
  servoAngle += servoDir; // change angle
  servo.write(servoAngle); // move servo
}

void step() {
  digitalWrite(stepPin, stepState);
  delay(1); // 1000 us
  digitalWrite(stepPin, !stepState);
}