//ESP32 + DHT-22 + DS18B20 + 74HC595(n) Test

//The code in this sketch is explained in detail in the DHT-22, the DS18B20 and the SN74HC595N pages
//and just combines the different codes.

/*========================================================================================================
 * DHT-22
 *========================================================================================================
*/
//Definitions and Pins
#define DHTTYPE DHT22         //define the DHT-xx sensor
const int DHTPIN = 15;        //define the Data Pin (GPIO 2)

//Libraries & Objects
#include <DHT.h>

DHT dht(DHTPIN, DHTTYPE);     //Represents sensor

//Variables
float dht22AirTem = 0;        //takes up new readings + final average
float dht22AirTemSum = 0;     //takes up the sum of readings for averaging
String dht22Temperature = ""; //gives back Temperature as a String for MQTT Transmission

float dht22RelHum = 0;        //takes up new readings + final average
float dht22RelHumSum = 0;     //takes up the sum of readings for averaging
String dht22Humidity = "";    //gives back Humidity as a String for MQTT Transmission

const uint8_t AveragingNumberDHT22 = 5; //Number of measurements to be averaged

/*========================================================================================================
 * DS18B20 
 *========================================================================================================
*/
//Definitions and Pins
const int ONE_WIRE_BUS = 14;      //=GPIO 14 of the ESP32 as 1-Wire Bus

//Libraries and Objects
#include <OneWire.h>            //Library for the 1-Wire protocol
#include <DallasTemperature.h>  //Library for sending commands and receiving data

DeviceAddress bottomSensorAddress = {0x28,0xC4,0xA0,0x51,0x38,0x19,0x01,0xC2};    //Address bottom sensor (sensor 1, Tape)
DeviceAddress surfaceSensorAddress = {0x28,0x0B,0xDB,0x60,0x38,0x19,0x01,0xA3};   //Address surface sensor (sensor 2, w/o Tape)
OneWire oneWire(ONE_WIRE_BUS);          //Object representing the 1-Wire bus
DallasTemperature DS18B20(&oneWire);  //Object representing the sensors

//Variables
float bottomTem = 0.00;         //for Temperature readings
String bottomTemperature = "";  //for the Sring to be sent using MQTT

float surfaceTem = 0.00;
String surfaceTemperature = "";

const uint8_t AveragingNumberDS18B20 = 5; //Number of measurements to be averaged

int RESOLUTION = 12;      //Resolution of the sensor
int TCONV = 750;          //Conversion time for resolution = 12
int delayTime = (TCONV/pow(2, (12-RESOLUTION))) + 10; //Necessary delay time after measuring to get new values, depending on resolution

/*========================================================================================================
 * Shift Register
 *========================================================================================================
*/
//Shift Register Pins
const int LATCHPIN = 2;
const int CLOCKPIN = 4;
const int DATAPIN = 0;

//Shift Register Pin Array
byte sensor_numbers[9] = {
  B00000000,  //all off
  B00000001,  //Pin 1
  B00000010,  //Pin 2
  B00000100,  //Pin 3
  B00001000,  //Pin 4
  B00010000,  //Pin 5
  B00100000,  //Pin 6
  B01000000,  //Pin 7
  B10000000,  //Pin 8
};

/*========================================================================================================
 * Setup
 *========================================================================================================
*/

void setup() {
  pinMode(LATCHPIN ,OUTPUT);
  pinMode(CLOCKPIN ,OUTPUT);
  pinMode(DATAPIN ,OUTPUT);
  
  Serial.begin(115200);
  delay(5000);
  Serial.println("Measurement is starting ...");
  Serial.println("==============================");
  Serial.println(delayTime);
}

/*========================================================================================================
 * Loop
 *========================================================================================================
*/

void loop() {
  Serial.println("Measuring ...");
  powerSwitch(2); //Turn DHT-22 ON
  measureDHTTemHum(AveragingNumberDHT22);
  powerSwitch(1); //LED Blink
  delay(200);
  powerSwitch(3); //Turn DS18B20s ON
  measureDS18B20Tem(AveragingNumberDS18B20);
  powerSwitch(1); //LED Blink
  delay(200);
  Serial.println("DHT-22 Measurement Results: ");
  Serial.println("Temperature:       " + dht22Temperature + " °C");
  Serial.println("Relative Humidity: " + dht22Humidity + " %");
  Serial.println("DS18B20 Measurement Results: ");
  Serial.println("Sensor 1 (Bottom) Measurement:  " + bottomTemperature + " °C");
  Serial.println("Sensor 2 (Surface) Measurement: " + surfaceTemperature + " °C");
  Serial.println("========================================");
}

/*========================================================================================================
 * Sensor and Shift Register Functions
 *========================================================================================================
*/

//DS18B20 Measurement function
void measureDS18B20Tem (const uint8_t AveragingNumber){
  DS18B20.begin();
  bottomTem = 0;
  surfaceTem = 0;
  bottomTemperature = "";
  surfaceTemperature = "";

  for(byte i = 0; i < AveragingNumber; i++)
  {
    DS18B20.requestTemperatures();
    delay(delayTime);
    bottomTem += DS18B20.getTempC(bottomSensorAddress);
    surfaceTem += DS18B20.getTempC(surfaceSensorAddress);
  }
  bottomTem /= AveragingNumber;
  surfaceTem /= AveragingNumber;

  if(bottomTem<10)
    bottomTemperature = "0";
  bottomTemperature += bottomTem;

  if(surfaceTem<10)
    surfaceTemperature = "0";
  surfaceTemperature += surfaceTem;
}

//DHT22 Measurement function
void measureDHTTemHum (const uint8_t AveragingNumber)
{
  dht.begin();                                          //activate Sensor
  delay(1000);                                          //to prevent unstable status (see Datasheet)
  dht22AirTemSum = 0;
  dht22RelHumSum = 0;
  dht22Temperature = "";
  dht22Humidity = "";
  for (byte i = 0; i < AveragingNumber; i++)            //take n measurements for both
  {
    do {                                                //execute this at least once
      dht22AirTem = dht.readTemperature();              //measure Temperature
      dht22RelHum = dht.readHumidity();                 //measure Humidity
      if (!isnan(dht22AirTem) && !isnan(dht22RelHum))   //if results are valid, add them to the sum
      {
        dht22AirTemSum += dht22AirTem;
        dht22RelHumSum += dht22RelHum;
      }
      else
        delay(2000);                                    //if measurement is invalid, it has to be repeated. Sensor must not heat up
    } while (isnan(dht22AirTem) || isnan(dht22RelHum)); //if results were invalid, repeat the loop
    if (i < (AveragingNumber - 1))                      //after the last measurement, there is no delay needed anymore
      delay(2000);
  }
  dht22AirTem = dht22AirTemSum / AveragingNumber;       //averaging the measurements to get more accurate results
  if(dht22AirTem<10)                                    //if the Temperature is below 10°C, add a 0 to the front of the String
    dht22Temperature = '0';
  dht22Temperature = dht22Temperature + dht22AirTem;
  
  dht22RelHum = dht22RelHumSum / AveragingNumber;
  if(dht22RelHum<10)
    dht22Humidity = '0';
  dht22Humidity = dht22Humidity + dht22RelHum;
}

//Shift Register Power Switch
void powerSwitch(byte pin){
  digitalWrite(LATCHPIN, LOW);
  shiftOut(DATAPIN, CLOCKPIN, MSBFIRST, sensor_numbers[pin]);
  digitalWrite(LATCHPIN, HIGH);
}