/* How to use the DHT-22 sensor with Arduino uno
   Temperature and humidity sensor
*/

//Libraries
#include <DHT.h>;
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27,20,4);
//Constants
#define DHTPIN1 2
#define DHTPIN2 4     // what pin we're connected to
#define DHTTYPE DHT22   // DHT 22  (AM2302)
DHT dht1(DHTPIN1, DHTTYPE);
DHT dht2(DHTPIN2, DHTTYPE); //// Initialize DHT sensor for normal 16mhz Arduino


//Variables
int chk;
long delay_count = 0;
float hum1;  //Stores humidity value
float temp1;
float hum2;  //Stores humidity value
float temp2;
float mean_temp;
float mean_hum;//Stores temperature value
float prev_mean_hum;
int set_hum = 50;
const int UP_pin = 8;
const int DOWN_pin = 9;

int UP = LOW;
int DOWN = LOW;

void display(float mean_temp, float mean_hum){
  lcd.setCursor(1,0);
  lcd.print("HUMID: ");
  lcd.print(mean_hum);
  lcd.print(" %");
  lcd.setCursor(1,1);
  lcd.print("TEMP: ");
  lcd.print(mean_temp);
  lcd.println(" C");  
}

bool hum_check(float hum1, float hum2, float mean_hum, int set_hum){
  if ((abs(hum1-hum2) <= 5) && ((set_hum-mean_hum) > 1.5)){
    return true;
  }
  else {
    return false;
  }
}

void setup()
{
  lcd.init();                      // initialize the lcd 
  lcd.backlight();
  lcd.setCursor(1,0);
  lcd.print("POWERING ON");
  Serial.begin(9600);
  dht1.begin();
  dht2.begin();
  pinMode(7, OUTPUT);
  lcd.begin(16,2);

  pinMode(UP_pin, INPUT);
  pinMode(DOWN_pin, INPUT);
  delay(500);
  hum1 = dht1.readHumidity();
  temp1 = dht1.readTemperature();
  hum2 = dht2.readHumidity();
  temp2 = dht2.readTemperature();
  mean_temp = (temp1+temp2)/2;
  mean_hum = (hum1+hum2)/2;  
  display(mean_temp, mean_hum);
}

void loop()
{
    prev_mean_hum = mean_hum;
    if (delay_count == 100000){
    //Read data and store it to variables hum and temp
    hum1 = dht1.readHumidity();
    temp1 = dht1.readTemperature();
    hum2 = dht2.readHumidity();
    temp2 = dht2.readTemperature();
    mean_temp = (temp1+temp2)/2;
    mean_hum = (hum1+hum2)/2;
    
  if (mean_hum != prev_mean_hum){
    lcd.clear();
    display(mean_temp, mean_hum);
  }
  else {
    display(mean_temp, mean_hum);
  }

    if (hum_check(hum1, hum2, mean_hum, set_hum)){
      digitalWrite(7, HIGH);
    }
    else{
      digitalWrite(7, LOW);
    }
    delay_count = 0;
    }
    ++delay_count;
  
  if ((UP == HIGH) && (set_hum <= 100)){
    ++set_hum;
    lcd.clear();
    lcd.setCursor(1,0);
    lcd.print("SET HUMIDITY: ");
    lcd.setCursor(1,1);
    lcd.print(set_hum);
    lcd.print(" %");
    UP = LOW;
    delay(150);
  }
  if ((DOWN == HIGH) && (set_hum >= 0)){
    --set_hum;
    lcd.clear();
    lcd.setCursor(1,0);
    lcd.print("SET HUMIDITY: ");
    lcd.setCursor(1,1);
    lcd.print(set_hum);
    lcd.print(" %");
    DOWN = LOW;
    delay(150);
  }
  UP = digitalRead(UP_pin);
  DOWN = digitalRead(DOWN_pin);

  if (abs(hum1-hum2) >= 10){
    lcd.setCursor(1,0);
    lcd.print("LARGE SENSOR    ");
    lcd.setCursor(1,1);
    lcd.print("DISPARITY       ");
    delay(2000);
    lcd.clear();
    hum1 = dht1.readHumidity();
    hum2 = dht2.readHumidity();
  }


}