/* Light Sense.
   A light sensor connected to Port 1 is used to distinguish three colours.
   Last updated.
   2.4.02
 */

#include "H8.h"
#include "InputPorts.h"
#include "LCD.h"
#include "Speaker.h"
#include "Buttons.h"
#include "Math.h"


#ifndef   LightSense_H_DEFINED
#define   LightSense_H_DEFINED

/* A light sensor is connected to Port 1. A light value is interpreted as 
   one of three colours by means of simple thresholds. The thresholds 
   are determined by means of an initial calibration. If a light value 
   is outside the possible light values, the light value is interpreted as 
   an undefined reading.
 */

/* Range of possible light values. */
#define MinLightValue   340
#define MaxLightValue   950

/* Minimum and maximum readings for a given colour under calibration. */
static uint16 Colour1Min, Colour1Max;
static uint16 Colour2Min, Colour2Max;
static uint16 Colour3Min, Colour3Max;

/* Thresholds calculated from the max and min readings. */
static uint16 Colour1Threshold;
static uint16 Colour2Threshold;  
static uint16 Colour3Threshold;   

enum Colour_t { UnDef = 4, Colour1 = 1, Colour2 = 2, Colour3 = 3};
typedef enum Colour_t Colour;

#define CALIBRATE_N  32 

void EstimateMinMaxValue ( byte id , uint16 * Min, uint16 * Max )
{
  uint16 i, value, max = 0 , min = 1023; 

  lcd_show_digit(id);
  while( ! Prgm ) lcd_show_int16(Port1Raw());
  
  for (i=0;i < CALIBRATE_N;i++){
    value = Port1Raw();
    if ( value < min ) min = value;
    if ( value > max ) max = value;  
  }

  * Min = min; * Max = max;
  
  lcd_show_int16(min);   lcd_show_digit(8); BusyPauseMS(2000);
  lcd_show_int16(max);   lcd_show_digit(9); BusyPauseMS(2000);
}

void LightSenseCalibrate( void ){


  EstimateMinMaxValue( 1, & Colour1Min, & Colour1Max );
  EstimateMinMaxValue( 2, & Colour2Min, & Colour2Max );
  EstimateMinMaxValue( 3, & Colour3Min, & Colour3Max );

  while( ! View ); while( View );

  SpeakerPlay(3,150);

  Colour1Threshold  =    (Colour2Min + Colour1Max) / 2;
  Colour2Threshold  =    (Colour3Min + Colour2Max) / 2; 
  Colour3Threshold  =     MaxLightValue;

  lcd_show_int16(Colour1Threshold); lcd_show_digit(1); BusyPauseMS(3000);
  lcd_show_int16(Colour2Threshold); lcd_show_digit(2); BusyPauseMS(3000);
  lcd_show_int16(Colour3Threshold); lcd_show_digit(3); BusyPauseMS(3000);
}


Colour LightSenseColour( void )
{
  Colour result; uint16 RawValue;

  result   = UnDef;
  RawValue = Port1Raw();

  if ( RawValue < MinLightValue         ) result = UnDef;    else
  if ( RawValue < Colour1Threshold      ) result = Colour1;  else
  if ( RawValue < Colour2Threshold      ) result = Colour2;  else
  if ( RawValue < Colour3Threshold      ) result = Colour3;  else  
                                          result = UnDef; 
  return result;
}


void LightSenseInit( void )
{
  SpeakerInit();
  Port1SetActive();
  LightSenseCalibrate();
}

void LightSenseClose( void )
{
  Port1SetPassive();
}


#endif /* LightSense_H_DEFINED */