/* Arduino example code for DHT11, DHT22/AM2302 and DHT21/AM2301 temperature and humidity sensors. More info: www.www.makerguides.com */

// Include the libraries:
#include <Adafruit_Sensor.h>
#include <DHT.h>
#include <EEPROM.h>

#define SAMPLE_TIME 2000  //The time between each EEPROM write function call in ms
 
int tempPin = 0;      //the ADC pin
int printPin = 2;     //the print button pin
int erasePin = 4;    //the erase button pin
int sensor = 3;              // the pin that the sensor is atteched to
int state = LOW;             // by default, no motion detected
int val = 0;                 // variable to store the sensor status (value)
 
int address = 0;      //EEPROM address counter
 
unsigned long timer;
 
float conv_coeff = 0.0;   //coefficient for converting from 0-1024 to 0-5 range
 
void printTemp();
void clearEEPROM();
void writeTemp();

// Set DHT pin:
#define DHTPIN 2

// Set DHT type, uncomment whatever type you're using!
//#define DHTTYPE DHT11   // DHT 11 
#define DHTTYPE DHT22   // DHT 22  (AM2302)
//#define DHTTYPE DHT21   // DHT 21 (AM2301)

// Initialize DHT sensor for normal 16mhz Arduino:
DHT dht = DHT(DHTPIN, DHTTYPE);

void setup() {
  // Begin serial communication at a baud rate of 9600:
  Serial.begin(9600);

  // Setup sensor:
  dht.begin();

  pinMode(sensor, INPUT);    // initialize sensor as an input

  conv_coeff = 4;  //find the coefficient to do the conversion
  timer = millis();         //millis() returns the time since program start in ms
  clearEEPROM();
}

void loop() {
  // Wait a few seconds between measurements:
  delay(2000);

  val = digitalRead(sensor);   // read sensor value
  if (val == HIGH) {           // check if the sensor is HIGH
    
    if (state == LOW) {
      Serial.println("Motion detected!"); 
      state = HIGH;       // update variable state to HIGH
    }
  } 
  else {
      
      if (state == HIGH){
        Serial.println("Motion stopped!");
        state = LOW;       // update variable state to LOW
    }
  }

  // Reading temperature or humidity takes about 250 milliseconds!
  // Sensor readings may also be up to 2 seconds 'old' (its a very slow sensor)

  // Read the humidity in %:
  float h = dht.readHumidity();
  // Read the temperature as Celsius:
  float t = dht.readTemperature();

  // Check if any reads failed and exit early (to try again):
  if (isnan(h) || isnan(t)) {
    Serial.println("Failed to read from DHT sensor!");
    return;
  }

  // Compute heat index in Celsius:
  float hic = dht.computeHeatIndex(t, h, false);


  Serial.print("Humidity: ");
  Serial.print(h);
  Serial.print(" % |");
  Serial.print("Temperature: ");
  Serial.print(t);
  Serial.print(" \xC2\xB0");
  Serial.print("C | ");
  Serial.print("Heat index: ");
  Serial.print(hic);
  Serial.print(" \xC2\xB0");
  Serial.println("C | ");

  EEPROM.write(address, hic * conv_coeff);         //write value to current address counter address
 
  Serial.print("Sensor value stored at address ");
  Serial.println(address);
   
  address++;                      //increment address counter
  if(address == EEPROM.length())  //check if address counter has reached the end of EEPROM
  {
    printTemp();             //if yes: reset address counter
  }
  if(address == 20)
  {
    printTemp();
  }
}

void printTemp()
{
  for (int i = 0 ; i < EEPROM.length() ; i++) {
    byte value = EEPROM.read(i);                //read EEPROM data at address i
    if(value != 0)                              //skip "empty" addresses
    {
      float temp = value / conv_coeff;            //convert ADC values to temperature
      //temp = (temp - 0.5)*100;                  //take care of the offset
 
      Serial.println(temp);
    }
  }
}

void clearEEPROM()
{
  for (int i = 0 ; i < EEPROM.length() ; i++) {
    if(EEPROM.read(i) != 0)                     //skip already "empty" addresses
    {
      EEPROM.write(i, 0);                       //write 0 to address i
    }
  }
  Serial.println("EEPROM erased");
  address = 0;                                  //reset address counter
}