startracker/arduino/jjrobots.ino

// STARTRACKER MOTOR CONTROL: STEPPER MOTOR CONTROL FOR JJROBOTS POV DISPLAY
// This code is designed for JJROBOTS arDusplay Stepper Motor Control board
// Author: JJROBOTS.COM (Jose Julio & Juan Pedro)
// Licence: GNU GPL
// Stepper : NEMA17
// Driver : A4988 or DRV8825
// Microstepping : configured to 1/16
// Arduino board: Pro micro (leonardo equivalent)

// STEPPER DRIVER CONNECTED TO:
// ENABLE pin: D10   (PB6)
// DIR pin:  D9      (PB5) 
// STEP pin: D8      (PB4)
// Button1 : START/STOP  D4
// Button2 : DEC   D5
// Button3 : CHANGE ROTATION DIRECTION (go back to original position)  D6

//DO NO TAKE PHOTOS WITH AN EXPOSITION LONGER THAN 5 MINUTES. THE DRIFT WOULD BE NOTICEABLE.

//Theory behind this CODE
//-----------------------------------------
// 360º (rotation of the Earth every 1436min)
// *Using a M8 rod coming up 1.25mm every complete rotation

#define COMINGUPSPEED 1.25  //milimeters that the rod comes up every complete rotation (360º). In a M8 rod/bolt is usually 1.25 mm. In a M6, only 1.00mm


//other info needed:
//ratio between the large gear and the small one=0.2549

//MEASURE THIS VALUE AS GOOD AS YOU CAN AND SET THE LENGHT BELOW
#define LENGTH 228 //distance from the centre of the hinge to the centre of the hole for the rod in milimiters


// Calculus here:
#define STEP ((2*3.14159)/1436)*LENGTH //rotational velocity of the small gear

#define RPS (STEP/(60*0.2549))/COMINGUPSPEED //rotational velocity of the large gear


#define ZERO_SPEED 65535
#define STEPS_PER_REV 3200     // 200 steps motor with 1/16 microstepping
#define MAX_RPM (RPS*60.0)   

static const unsigned int led_pin = 7;
static const unsigned int step_pin = 8;
static const unsigned int dir_pin = 9;
static const unsigned int enable_pin = 10;

static const unsigned int btn1_pin = 4;
static const unsigned int btn2_pin = 11;
static const unsigned int btn3_pin = 6;

static const unsigned int serial_speed = 115200;

// BIT functions
#define CLR(x,y) (x&=(~(1<<y)))
#define SET(x,y) (x|=(1<<y))

//uint16_t rpm;
float rpm;
uint16_t period;
uint16_t userCommand=0;

static bool motor_enable;

// TIMER 1: STEP INTERRUPT
ISR(TIMER1_COMPA_vect)
{
  if (motor_enable)
    {
      SET(PORTB, step_pin);
      delayMicroseconds(2);
      CLR(PORTB, step_pin);
    }
}

void setRpm()
{
  float temp;
  if (rpm == 0)
    {
      ICR1 = ZERO_SPEED;
      digitalWrite(enable_pin, HIGH);  // Disable motor
    }
  else
    {
      digitalWrite(enable_pin, LOW);  // Enable motor
      /*   if (rpm<8)
	   rpm = 8;*/
      if (rpm>MAX_RPM)
	rpm = MAX_RPM;
      temp = (rpm/60.0)*STEPS_PER_REV;
      temp = 2000000 / temp;          //  2000000 = (16000000/8) timer1 16Mhz with 1/8 preescaler
      if (period<600000)
	period=60000;
      period = temp;
      while (TCNT1 < 30);   // Wait until a pulse to motor has finished
      //cli();
      ICR1 = period; //+ userCommand;
      if (TCNT1 > ICR1)     // Handle when we need to reset the timer
	TCNT1=0;
      //sei();
    }
}

void setup()
{
 
  // Setup PIN as GPIO output
  pinMode(led_pin, OUTPUT);    // LED pin
  pinMode(step_pin, OUTPUT);    // STEP pin
  pinMode(dir_pin, OUTPUT);    // DIR pin
  pinMode(enable_pin, OUTPUT);   // ENABLE pin
  
  // Button input with pullups enable
  pinMode(btn1_pin, INPUT_PULLUP);
  pinMode(btn2_pin, INPUT_PULLUP);
  pinMode(btn3_pin, INPUT_PULLUP);

  // Initial setup for motor driver
  digitalWrite(enable_pin, HIGH);  // Disable motor
  digitalWrite(dir_pin, HIGH);     // Motor direction

  // debug output
  Serial.begin(serial_speed);

  digitalWrite(led_pin, HIGH);
  delay(200);    // Initial delay
  digitalWrite(led_pin, LOW);

  motor_enable = false;
  
  // PWM SETUP
  // Fast PWM mode => TOP:ICR1
  TCCR1A =(1<<WGM11);           
  //  TCCR1B = (1<<WGM13)|(1<<WGM12)|(1<<CS10);   //No Prescaler, Fast PWM
  TCCR1B = (1<<WGM13)|(1<<WGM12)|(1<<CS11);   // Prescaler 1:8, Fast PWM
  ICR1 = ZERO_SPEED;
  TIMSK1 = (1<<OCIE1A);  // Enable Timer interrupt
  
  rpm = 0;
  
  while (digitalRead(4)==HIGH);    // Wait until START button is pressed
  motor_enable = true;
  delay(250);
  while (digitalRead(4)==LOW);
}

void loop()
{ 
  if (digitalRead(btn1_pin)==LOW)   // START/STOP Button pressed?
    {
      rpm = 0;
      userCommand=0;
      setRpm();

      motor_enable = !motor_enable;

      /* if (motor_enable) */
      /*   motor_enable = false; */
      /* else */
      /*   motor_enable = true; */

      while (digitalRead(btn1_pin)==LOW);   // Wait until botton release
    }
    
  if (digitalRead(btn3_pin)==LOW)   //  Button 3 pressed?
    {
      Serial.println("Coming back");
	
      digitalWrite(btn3_pin, HIGH);    // Motor direction

      rpm=50; 
      setRpm();
	
      if (motor_enable == 1)
	motor_enable = 0;
      else
	motor_enable = 1;
         
      while (digitalRead(btn3_pin)==LOW);   // Wait until botton release
    }
    
    
  if (motor_enable)
    {
      rpm++;
      digitalWrite(led_pin, HIGH);
    }
  else
    {
      rpm = 0;
      digitalWrite(led_pin, LOW);
    }
  Serial.print("RPM:");
  Serial.print(rpm);
  Serial.print(" ");
  Serial.println(period+userCommand);
  setRpm();
  Serial.print("100xRPS large gear:");
  Serial.print(RPS/0.2549);
  Serial.print(" ");
  Serial.print("STEP:");
  Serial.print(STEP);
  Serial.print(" ");
  delay(10);
  
  if (digitalRead(btn2_pin)==LOW)   // Decrease button
    {
      digitalWrite(led_pin, LOW);
      userCommand--;
      while (digitalRead(btn2_pin)==LOW);  // Wait until released
    }
  if (digitalRead(btn3_pin)==LOW)   // Increase button
    {
      digitalWrite(led_pin, LOW);
      userCommand++;
      while (digitalRead(btn3_pin)==LOW);  // Wait until released
    }
}