// Temperature Controler for window fan
// Written by mike, public domain

/*--------------------------------------------------------------------------------------
Includes
--------------------------------------------------------------------------------------*/
#include "DHT.h"
#include <LiquidCrystal.h> // include LCD library

/*--------------------------------------------------------------------------------------
Defines
--------------------------------------------------------------------------------------*/
// Pins in use
#define DHTPIN 2 // D2 is for DHT22
#define OUTPUTPIN 3 // Relay pin
#define BUTTON_ADC_PIN A0 // A0 is the button ADC input
// ADC readings expected for the 5 buttons on the ADC input
#define RIGHT_10BIT_ADC 0 // right
#define UP_10BIT_ADC 131 // up
#define DOWN_10BIT_ADC 305 // down
#define LEFT_10BIT_ADC 476 // left
#define SELECT_10BIT_ADC 718 // select
#define BUTTONHYSTERESIS 20 // hysteresis for valid button sensing window

//return values for ReadButtons()
#define BUTTON_NONE 0 //
#define BUTTON_RIGHT 1 //
#define BUTTON_UP 2 //
#define BUTTON_DOWN 3 //
#define BUTTON_LEFT 4 //
#define BUTTON_SELECT 5 //
#define DHTTYPE DHT22 // DHT 22 (AM2302)
// Define our states
#define STATE_TITLE 00 // A title screen
#define STATE_MODE 05 // Waiting for mode selection
#define STATE_HEATING 10 // Heating Mode
#define STATE_COOLING 20 // Cooling Mode

DHT dht(DHTPIN, DHTTYPE);
LiquidCrystal lcd( 8, 9, 4, 5, 6, 7 ); //Pins for the freetronics 16x2 LCD shield. LCD: ( RS, E, LCD-D4, LCD-D5, LCD-D6, LCD-D7 )


/*--------------------------------------------------------------------------------------
Variables
--------------------------------------------------------------------------------------*/
float hi = 0;
float h = 0;
float t = 0;
float f = 0;
byte buttonJustPressed = false; //this will be true after a ReadButtons() call if triggered
byte buttonJustReleased = false; //this will be true after a ReadButtons() call if triggered
byte buttonWas = BUTTON_NONE; //used by ReadButtons() for detection of button events
byte button = BUTTON_NONE; // return no button pressed if the below checks don't write to btn
byte state, nextstate;
int Temperature_Set_Point = 71;
unsigned int buttonVoltage;
int relayState = LOW;
int fanState = HIGH;

void setup() {
Serial.begin(9600);
Serial.println("DHTxx test!");
pinMode(BUTTON_ADC_PIN, INPUT ); // Analogue input for the LCD's buttons
pinMode(OUTPUTPIN, OUTPUT );
digitalWrite(OUTPUTPIN, relayState );
dht.begin();
lcd.begin( 16, 2 ); // Tell LCD library this is 16x2 display

// TITLE

lcd.clear();
// 1234567890123456
lcd.print( "THERMOSTAT" );
lcd.setCursor( 0, 1 );
// 1234567890123456
lcd.print( "Version .3" );
delay (2000);

lcd.clear();
}

void loop() {
h = dht.readHumidity();
f = dht.readTemperature(true);
hi = dht.computeHeatIndex(f, h);

if (fanState && !relayState && Temperature_Set_Point < f - 1) {
relayState = HIGH;
digitalWrite(OUTPUTPIN, relayState);
}
if ((!fanState) || (relayState && Temperature_Set_Point >= f)) {
relayState = LOW;
digitalWrite(OUTPUTPIN, relayState);
}

lcd.setCursor( 0, 0 );
lcd.print(Temperature_Set_Point);
lcd.print("F");lcd.setCursor( 10, 0 );
lcd.print(f);
lcd.print("F");
lcd.setCursor( 0, 1 );
lcd.print(relayState);
lcd.setCursor( 3, 1 );
lcd.print(h);
lcd.setCursor( 10, 1 );
lcd.print(hi);
lcd.print("F");

delay(500); // Delay to stop buttons "jittering" false presses

button = ReadButtons();

while (button == BUTTON_UP) {
Temperature_Set_Point = Temperature_Set_Point + 1;
lcd.setCursor( 0, 0 );
lcd.print(Temperature_Set_Point);
lcd.print("F");
delay(500); // Delay to stop buttons "jittering" false presses
button = ReadButtons();
}
while (button == BUTTON_DOWN) {
Temperature_Set_Point = Temperature_Set_Point - 1;
lcd.setCursor( 0, 0 );
lcd.print(Temperature_Set_Point);
lcd.print("F");
delay(500); // Delay to stop buttons "jittering" false presses
button = ReadButtons();
}
while (fanState && button == BUTTON_SELECT) {
fanState = LOW;
delay(500); // Delay to stop buttons "jittering" false presses
button = ReadButtons();
}
while (!fanState && button == BUTTON_SELECT) {
fanState = HIGH;
delay(500); // Delay to stop buttons "jittering" false presses
button = ReadButtons();
}

//clear the buttonJustPressed & buttonJustReleased flags; they've already done their job
if(buttonJustPressed) buttonJustPressed = false;
if(buttonJustReleased) buttonJustReleased = false;

Serial.print("Humidity: ");
Serial.print(h);
Serial.print(" %\t");
Serial.print("Temperature: ");
Serial.print(f);
Serial.print(" *F\t");
Serial.print("Heat index: ");
Serial.print(hi);
Serial.println(" *F");
}

/*--------------------------------------------------------------------------------------
ReadButtons()
Detect the button pressed and return the value
Uses global values buttonWas, buttonJustPressed, buttonJustReleased.
--------------------------------------------------------------------------------------*/
byte ReadButtons() {
unsigned int buttonVoltage;
byte button = BUTTON_NONE; // return no button pressed if the below checks don't write to btn

//read the button ADC pin voltage
buttonVoltage = analogRead( BUTTON_ADC_PIN );
//sense if the voltage falls within valid voltage windows
if( buttonVoltage < ( RIGHT_10BIT_ADC + BUTTONHYSTERESIS ) )
{
button = BUTTON_RIGHT;
}
else if( buttonVoltage >= ( UP_10BIT_ADC - BUTTONHYSTERESIS )
&& buttonVoltage <= ( UP_10BIT_ADC + BUTTONHYSTERESIS ) )
{
button = BUTTON_UP;
}
else if( buttonVoltage >= ( DOWN_10BIT_ADC - BUTTONHYSTERESIS )
&& buttonVoltage <= ( DOWN_10BIT_ADC + BUTTONHYSTERESIS ) )
{
button = BUTTON_DOWN;
}
else if( buttonVoltage >= ( LEFT_10BIT_ADC - BUTTONHYSTERESIS )
&& buttonVoltage <= ( LEFT_10BIT_ADC + BUTTONHYSTERESIS ) )
{
button = BUTTON_LEFT;
}
else if( buttonVoltage >= ( SELECT_10BIT_ADC - BUTTONHYSTERESIS )
&& buttonVoltage <= ( SELECT_10BIT_ADC + BUTTONHYSTERESIS ) )
{
button = BUTTON_SELECT;
}
//handle button flags for just pressed and just released events
if( ( buttonWas == BUTTON_NONE ) && ( button != BUTTON_NONE ) )
{
//the button was just pressed, set buttonJustPressed, this can optionally be used to trigger a once-off action for a button press event
//it's the duty of the receiver to clear these flags if it wants to detect a new button change event
buttonJustPressed = true;
buttonJustReleased = false;
}
if( ( buttonWas != BUTTON_NONE ) && ( button == BUTTON_NONE ) )
{
buttonJustPressed = false;
buttonJustReleased = true;
}

//save the latest button value, for change event detection next time round
buttonWas = button;

return( button );
}