/******************   Arduino SPI with DHT22 and UltraSonic ******************/
/****************** 240x320 2.8" LCD-TFT display with SPI interface  *********/
#include "SPI.h"
#include "Adafruit_GFX.h"
#include "Adafruit_ILI9341.h"
#define TFT_DC 9
#define TFT_CS 10
Adafruit_ILI9341 tft = Adafruit_ILI9341(TFT_CS, TFT_DC);

// DHT lib
#include <Adafruit_Sensor.h>
#include <DHT.h>
// DHT22
#define DHTPIN 2    
#define DHTTYPE DHT22   
DHT dht(DHTPIN, DHTTYPE);
//Variables
float hum;  //Stores humidity value
float temp; //Stores temperature value
float dis;
float converted = 0.00;
// Sonic Sensor
#define ECHO_PIN 4
#define TRIG_PIN 3

void setup()
{
  tft.begin();
  // Initialize device.
  dht.begin();
  // Sonic
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  //Rotate the screen to right direction
  tft.setRotation(1);
  //Print the headers
  printHeader();
}

void loop() 
{ 
  //Read data and store it to variables hum and temp
  hum = dht.readHumidity();
  temp= dht.readTemperature();
  printSensorData();
}

//Print headers
unsigned long printHeader(void )
{
  tft.fillRect(0,  0, 200, 64, ILI9341_GREEN);
  tft.fillRect(0, 64, 200, 64, ILI9341_RED);
  tft.fillRect(0,128, 200, 64, ILI9341_CYAN);
  tft.fillRect(0,192, 200, 64, ILI9341_ORANGE);

  unsigned long start = micros();
  tft.setTextColor(ILI9341_BLACK);   
  tft.setTextSize(3);

  tft.setCursor(50, 0+20);
  tft.print("CELCIUS");

  tft.setCursor(50, 64+20);
  tft.print("KELVIN");

  tft.setCursor(50, 128+20);
  tft.print("HUMIDITY");

  tft.setCursor(50, 192+20);
  tft.print("DISTANCE");
  return micros() - start;
    
}

unsigned long printSensorData() 
{
  tft.fillRect(201,  0, 240, 64,ILI9341_ORANGE);
  tft.fillRect(201, 64, 240, 64,ILI9341_CYAN);
  tft.fillRect(201,128, 240, 64,ILI9341_RED);
  tft.fillRect(201,192, 240, 64,ILI9341_GREEN);

  unsigned long start = micros();
  tft.setTextColor(ILI9341_BLACK);   
  tft.setTextSize(2);
        
  tft.setCursor(201,0+20);
  tft.print(temp);
  tft.print(" ");
  tft.print((char)247);
  tft.println("C");
//Kelvin
    //T(K) = T(°C) + 273.15          
    converted = temp + 273.15;
  tft.setCursor(201,64+20);
  tft.print(converted);
  tft.print(" ");
  tft.println("K");
 //Humidity
  tft.setCursor(201,128+20);
  tft.print(hum);
  tft.print(" ");
  tft.println("%");
// Distance
  dis = readDistanceCM();
  tft.setCursor(201,192+20);
  tft.print(dis);
  tft.print(" ");
  tft.println("cm");
  
  return micros() - start;
}

float readDistanceCM() {
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  int duration = pulseIn(ECHO_PIN, HIGH);
  return duration * 0.034 / 2;
}