// main time constants
#define NumberOfPhotos 3
#define PhotoSavingTime 200
#define InitialWait 700

// shutter release time constants
#define ConfirmShutter 30
#define PressedShutter 40
#define UnpressShutter 50

// motors & sensors
#define RotationMotor OUT_A
#define ShutterMotor OUT_C
#define ShutterSense SENSOR_1
#define RotationSense SENSOR_2

#define CalibrateTime 15
#define Hyster 10
#define CountPerTurn 80

// Threshold for the light sensor encoder 
int Threshold;
// Position of the panoramic head
int RotAngle;

int count=0;

task main()
{
  SetSensor(ShutterSense,SENSOR_TOUCH);
  SetSensorType(RotationSense,SENSOR_TYPE_LIGHT);
  SetSensorMode(RotationSense,SENSOR_MODE_RAW);
  SetPower(RotationMotor,2);

  Wait(InitialWait);
  
  Calibrate();
  RotAngle=0;
  start CountRotation;

  while (count < NumberOfPhotos)
  {
    count++;
    
    PlaySound(1);
    ShutterRelease();    
    Wait(PhotoSavingTime);
    
    OnRev(RotationMotor);
    until (RotAngle >= (count * CountPerTurn)/NumberOfPhotos);
    Off(RotationMotor);
  }

  Float(RotationMotor+ShutterMotor);
  StopAllTasks();
}


// As name implies, press the shutter release button...

sub ShutterRelease()
{
  OnRev(ShutterMotor);
  until (ShutterSense == 1);
  Wait(ConfirmShutter);
  Off(ShutterMotor);
  Wait(PressedShutter);
  OnFwd(ShutterMotor);
  Wait(UnpressShutter);
  Off(ShutterMotor);
}


// Measures the light in white and black zones of the encoder
// and place the threshold in-between
// As an added bonus, finish by rotating the head in forward direction,
// thus compensating looseness of gears

sub Calibrate()
{
  int low = 1000;
  int high = 0;
  int temp; 
  Wait(50);
  OnFwd(RotationMotor);
  repeat (CalibrateTime)
  {
    temp = RotationSense;
    if (temp < low)
    {
      low = temp;
    }
    if (temp > high)
    {
      high = temp;
    }
    Wait(1);
  }
  Off(RotationMotor);
  Wait(50);
  OnRev(RotationMotor);
  repeat (CalibrateTime)
  {
    temp = RotationSense;
    if (temp < low)
    {
      low = temp;
    }
    if (temp > high)
    {
      high = temp;
    }
    Wait(1);
  }
  Off(RotationMotor);
  Wait(50);
  Threshold = (high+low)/2;
}


//Counts the number of transitions between black and white

task CountRotation()
{
  while (true)
  {
    until (RotationSense < Threshold - Hyster);
    RotAngle++;
    until (RotationSense > Threshold + Hyster);
    RotAngle++;
  }
}