Shutter

#include <math.h>

int pwmPin = 9; // output pin supporting PWM
int inPin = 2; // voltage connected to analog pin 3, e.g. a potentiometer
int aperturePin = 3; //Pin 2 for aperture selection.
int pushButton = 2;



void setup()
{
  pinMode(pushButton, INPUT);
  pinMode(pwmPin, OUTPUT); // sets the pin as output
  TCCR1B = TCCR1B & 0b11111000 | 0x01; //31250 hz
  Serial.begin(9600);
}

void loop()
{


  analogWrite(pwmPin, 0);



  int buttonState = digitalRead(pushButton);

  if(buttonState == 1){

    shutter(analogRead(3),analogRead(inPin));  //47 max, 25 min.
  }

}






void delay_x(uint32_t millis_delay)
{
  uint16_t micros_now = (uint16_t)micros();

  while (millis_delay > 0) {
    if (((uint16_t)micros() - micros_now) >= 1000) {
      millis_delay--;
      micros_now += 1000;
    }
  }
}





int shutter(float aperture, float shutterSpeed)
//Make sure no variables are out of bound
{
  if(shutterSpeed <= 4){
    shutterSpeed = 4;
  }



  if(aperture > 255){
    aperture = 255;
  }
  //Calculate actual aperture voltage
  //  float apertureBias = 6.477707151*exp(-63.42518309/aperture);
  float apertureBias = -4.073328941*pow(10,-2)*(exp(5.369935444*pow(10,-2))*aperture - exp(-4.073328941*pow(10,-2))*aperture)/(-4.073328941*pow(10,-2) - 5.369935444*pow(10,-2));


  float correctAperture = 9.821433066*pow(10,-1)*shutterSpeed/(shutterSpeed - apertureBias);
  correctAperture = aperture*correctAperture;
  //Warm up conductor
  analogWrite(pwmPin, 255);
  delay_x(1);
  analogWrite(pwmPin, 0);
  delay_x(1);



  //Feedback
  Serial.println(shutterSpeed);
  Serial.println(correctAperture);
  //Trigger shutter
  analogWrite(pwmPin, correctAperture);
  delay_x(shutterSpeed);   //shutter speed
  analogWrite(pwmPin, 0);
  delay_x(100);
  analogWrite(pwmPin, 0);
  return 1;
}