#include <p18cxxx.h>
#include <timers.h>
#include <pwm.h>
#include <usart.h>
#include <portb.h>
#include <delays.h>
#pragma config WDT = OFF, OSC = INTIO2, FSCM = OFF, IESO = OFF, LVP = OFF, MCLRE = OFF, STVR = OFF, DEBUG = OFF, WRT0 = OFF, WRT1 = OFF, CP0 = OFF, CP1 = OFF, CPD = OFF, BOR = OFF



#define NUMPERIODS 4
#define RELAYPIN LATBbits.LATB3
#define PUSHBUTTON PORTBbits.RB4

unsigned char i;
unsigned char j;
unsigned int counts[NUMPERIODS];//will hold the number of 0-to-1 transitions in five 0.1 second timespans
unsigned char isawhistle;
unsigned char lightison = 0;
char statechangecount = 5; //without this, after the light switched, it would quickly switch back again the next time it checks if you're whistling. You need it to ignore whistling for about a half second to give you a chance to stop whistling.
char step=0;


void main (void)
{
	OSCCON = 0x70;	//set it to use the 8MHz internal clock.
	ADCON1 = 0x7F;	//set all ADC-capable pins to NOT be analog inputs, just digital IO.
	INTCON2bits.RBPU = 0; //PORTB pullup resistors enabled

	DDRB=0xFF;  //all inputs
	DDRA=0b00010000;
  	DDRAbits.RA4=1;	//this pin is the "external oscillator" input of Timer0. The comparator connects here, and Timer0 counts the number of 0 to 1 transitions.
  	DDRAbits.RA0=0; //will light an LED when a tone is detected.
  	DDRBbits.RB3=0;//runs the relay
  	DDRBbits.RB4=1;//for an alternative pushbutton, for people who can't whistle. (I ended up not putting this on the circuit though.)
  	PORTA=0;
  	PORTB=0;
  	
  	OpenTimer0( TIMER_INT_OFF &
            T0_16BIT &
            T0_SOURCE_EXT & //this setting means it is really just counting the number of 0 to 1 transitions on pin RA4
            T0_EDGE_RISE &
            T0_PS_1_1 );
  		
  	while(1)
  	{
	  	for(j=0; j<NUMPERIODS; j++)
	  	{
		  	WriteTimer0(0);
		  	Delay10KTCYx(20);//delays .1 seconds
		  	counts[j]=ReadTimer0();
			//The code below will run very quickly in between each .1-second timespan.
			//After each sample, check the five 0.1 second timespans. If they have roughly the same frequency in the right frequency range, it's a whistle.
			isawhistle = 1;//will be set to 0 if we discover otherwise
		  	for(i=1; i<NUMPERIODS; i++)
		  	{
			  	if((counts[i] > 1.15*counts[i-1]) || (counts[i] < 0.85*counts[i-1]) ) //if this is false, then they ARE within 15% of each other. 
			  	{
				  	isawhistle = 0;
				}
			  	
			}
			if((counts[2] < 90) || (counts[2] > 270))//in a 0.1 second timespan, this corresponds to a frequency range of 900 to 2700 Hz, which includes the range I can whistle but should exclude most noise. If counts[2] is within the range, then the others are close also.
			{
				isawhistle = 0;
			}
			
			
			
			if((statechangecount == 0) && ( (isawhistle == 1) || (PUSHBUTTON == 0)) ) //I turned on the weak pullup resistors, so the pushbutton will connect between the pin and ground, so when it's on, the pin sees 0V.
			{
				LATAbits.LATA0 = 1;//lights an LED momentarily to indicate a whistle was detected, for debugging.
				if(lightison == 1) //if the light is on, turn it off, and vice versa.
				{
					lightison = 0;
					RELAYPIN = 0;
					statechangecount = 5;
				}
				else
				{
					lightison = 1;
					RELAYPIN = 1;
					statechangecount = 5;
				}	
			}
			else
			{
				LATAbits.LATA0 = 0;
			}
			
			if(statechangecount > 0)
			{
				statechangecount--;
			}

		}
	}
	
}