How to Make Smart Home Using Arduino Control Relay Module

//Home Automation using Smart Relay V3 
//with Tempareture & Light controlled Auto Mode (Tech StudyCell)
//youtube.com/techstudycell

#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <Adafruit_Sensor.h>
#include <DHT.h>
#include <DHT_U.h>
#include <IRremote.h>

const float maxTemp = 28.2;
const float minTemp = 27.5;
const int ldrOn = 800;
const int ldrOff = 400;

//Define PIN constant
const int relay_1 = 2;
const int relay_2 = 3;
const int relay_3 = 4;
const int relay_4 = 5;
const int relay_5 = 6;

const int mswitch_1 = 7;
const int mswitch_2 = 8;
const int mswitch_3 = 9;
const int mswitch_4 = 10;
const int mswitch_5 = 11;
const int cmode = 12;
const int smode = 13;
int RECV_PIN = A0;

//Define IR receiver and Result Objects
IRrecv irrecv(RECV_PIN);
decode_results results;

//#define LDRPIN A2
#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 32 // OLED display height, in pixels

// Declaration for an SSD1306 display connected to I2C (SDA, SCL pins)
#define OLED_RESET     -1 // Reset pin # (or -1 if sharing Arduino reset pin)
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

#define DHTPIN A1     // Digital pin connected to the DHT sensor 

// Uncomment the type of sensor in use:
#define DHTTYPE    DHT11     // DHT 11

DHT_Unified dht(DHTPIN, DHTTYPE);

int toggleState_1 = 0; //Define integer to remember the toggle state for relay 1
int toggleState_2 = 0; //Define integer to remember the toggle state for relay 2
int toggleState_3 = 0; //Define integer to remember the toggle state for relay 3
int toggleState_4 = 0; //Define integer to remember the toggle state for relay 4
int toggleState_5 = 0; //Define integer to remember the toggle state for relay 5

int switchMode = 0;
int ModeFlag = 0;
int inloop;
float temperature;
float humidity;
String displayText;
int displayDelay;
uint32_t delayMS;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  irrecv.enableIRIn(); // Enable the IR receiver
  
  pinMode(relay_1, OUTPUT);
  pinMode(relay_2, OUTPUT);
  pinMode(relay_3, OUTPUT);
  pinMode(relay_4, OUTPUT);
  pinMode(relay_5, OUTPUT);

  pinMode(smode, INPUT);
  pinMode(cmode, INPUT);

  pinMode(mswitch_1, INPUT);
  pinMode(mswitch_2, INPUT);
  pinMode(mswitch_3, INPUT);
  pinMode(mswitch_4, INPUT);
  pinMode(mswitch_5, INPUT);
 
  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);  // Address 0x3C for 128x32
  display.setTextSize(1);
  display.setTextColor(WHITE);
  display.clearDisplay(); // Clear display buffer
  // Initialize device.
  dht.begin();
  sensor_t sensor;
  
  // Set delay .
  delayMS = 10;
}

void relayOnOff(int relay){

    switch(relay){
      case 1: 
             if(toggleState_1 == 0){
              digitalWrite(relay_1, HIGH); // turn on relay 1
              toggleState_1 = 1;
              }
             else{
              digitalWrite(relay_1, LOW); // turn off relay 1
              toggleState_1 = 0;
              }
             delay(100);
      break;
      case 2: 
             if(toggleState_2 == 0){
              digitalWrite(relay_2, HIGH); // turn on relay 2
              toggleState_2 = 1;
              }
             else{
              digitalWrite(relay_2, LOW); // turn off relay 2
              toggleState_2 = 0;
              }
             delay(100);
      break;
      case 3: 
             if(toggleState_3 == 0){
              digitalWrite(relay_3, HIGH); // turn on relay 3
              toggleState_3 = 1;
              }else{
              digitalWrite(relay_3, LOW); // turn off relay 3
              toggleState_3 = 0;
              }
             delay(100);
      break;
      case 4: 
             if(toggleState_4 == 0){
              digitalWrite(relay_4, HIGH); // turn on relay 4
              toggleState_4 = 1;
              }
             else{
              digitalWrite(relay_4, LOW); // turn off relay 4
              toggleState_4 = 0;
              }
             delay(100);
      break;
      case 5: 
             if(toggleState_5 == 0){
              digitalWrite(relay_5, HIGH); // turn on relay 5
              toggleState_5 = 1;
              }
             else{
              digitalWrite(relay_5, LOW); // turn off relay 5
              toggleState_5 = 0;
              }
             delay(100);
      break;      
      default : break;      
      }
  
}
String modeDecode(int count){
  if (count == 0){
    return " Manual Mode ";
  }
  else if (count == 1){
    return " Bluetooth Mode ";
  }
  else if (count == 2){
    return " Infrared Mode ";
  }
  else if (count == 3){
    return " Auto Mode ";
  }
}

void loop() {
  
  if (digitalRead(cmode) == HIGH){
    display.clearDisplay();
    display.setCursor(5,2);
    display.print("Set Mode ");
    display.display();
    delay(2000);
    Serial.println("inloop = 0");
    while(1){
      if (digitalRead(smode) == HIGH){  
        delay(300);      
        if (switchMode < 3){
          switchMode= switchMode + 1;
          Serial.println(switchMode);
        }
        else{
          switchMode =0;
          Serial.println(switchMode);
        }
        displayText= modeDecode(switchMode);
        display.clearDisplay();
        display.setCursor(5,2);
        display.print("Set Mode: ");
        display.println();
        display.drawLine(0,18, display.width()-1,18, WHITE);
        display.setCursor(15,24);
        display.print(displayText);     
        display.display();
      }
      if(digitalRead(cmode) == HIGH){
        delay(1000);
        Serial.println("inloop = 1  ");
        Serial.println(switchMode);
        display.clearDisplay();
        displayDelay = 500;
        break;
      }
    } 
  }     
  else{

  if (displayDelay == 500) {    
      displayDelay = 0;
      display.clearDisplay();
      // Get temperature event and print its value.
      sensors_event_t event;
      dht.temperature().getEvent(&event);
      if (isnan(event.temperature)) {
        Serial.println(F("Error reading temperature!"));
      }
      else {        
        display.setCursor(8,2);
        display.print(event.temperature);
        display.print(" C    ");     
        display.display();
        temperature = event.temperature;
      }    
      // Get humidity event and print its value.
      dht.humidity().getEvent(&event);
      if (isnan(event.relative_humidity)) {
        Serial.println(F("Error reading humidity!"));
      }
      else {
        display.print(event.relative_humidity);
        display.print(" %");     
        display.display();
        display.drawLine(0,18, display.width()-1,18, WHITE);
        displayText= modeDecode(switchMode);
        display.setCursor(15,24);
        display.print(displayText);   
        display.display();
        Serial.print(switchMode);
      }
  }
  displayDelay ++;
  if (switchMode == 0){  // Manual Mode
    Serial.print(F("Manual mode: "));
    if (digitalRead(mswitch_1) == HIGH){
      delay(200);
      relayOnOff(1);      
    }
    else if (digitalRead(mswitch_2) == HIGH){
      delay(200);
      relayOnOff(2);
    }
    else if (digitalRead(mswitch_3) == HIGH){
      delay(200);
      relayOnOff(3);
    }
    else if (digitalRead(mswitch_4) == HIGH){
      delay(200);
      relayOnOff(4);
    }
    else if (digitalRead(mswitch_5) == HIGH){
      delay(200);
      relayOnOff(5);
    }
  }
  else if (switchMode == 1){   //Bluetooth Mode
    if(Serial.available()>0)
   {     
      char data= Serial.read(); // reading the data received from the bluetooth module
      switch(data)
      {
        case 'Z': relayOnOff(1);break; // when Z is pressed on the app Turn on Relay 1
        case 'z': relayOnOff(1);break; // when z is pressed on the app Turn off Relay 1
        case 'Y': relayOnOff(2);break; // when Y is pressed on the app Turn on Relay 2
        case 'y': relayOnOff(2);break; // when y is pressed on the app Turn off Relay 2
        case 'W': relayOnOff(3);break; // when W is pressed on the app Turn on Relay 3
        case 'w': relayOnOff(3);break; // when w is pressed on the app Turn off Relay 3
        case 'V': relayOnOff(4);break; // when V is pressed on the app Turn on Relay 4
        case 'v': relayOnOff(4);break; // when v is pressed on the app Turn off Relay 4
        case 'U': relayOnOff(5);break; // when U is pressed on the app Turn on Relay 5
        case 'u': relayOnOff(5);break; // when u is pressed on the app Turn off Relay 5
        default : break;
      }
      Serial.println(data);
   }
   delay(100);
  }
  else if (switchMode == 2){  // Infrared Mode
    Serial.println("IR MODE");
      if (irrecv.decode(&results)) {
        switch(results.value){
          case 0x80BF49B6: 
                    relayOnOff(1);
          break;
          case 0x80BFC936: 
                    relayOnOff(2);
          break;
          case 0x80BF33CC: 
                    relayOnOff(3);
          break;
          case 0x80BF718E: 
                    relayOnOff(4);
          break;
          case 0x80BFF10E: 
                    relayOnOff(5);
          break;
          default : break;      
          }    
    irrecv.resume(); // Receive the next value
    }
  }
  else if (switchMode == 3){  //Auto Mode
    Serial.println("Auto Mode");
    int sensorVal = analogRead(A2);
  if (sensorVal >= ldrOn){
      if(toggleState_3 == 0){
        digitalWrite(relay_3, HIGH); // turn on relay 3
        toggleState_3 = 1;
      }
      else if(toggleState_4 == 0){
        digitalWrite(relay_4, HIGH); // turn on relay 4
        toggleState_4 = 1;
      }
  }
  else if (sensorVal < ldrOff){
    if(toggleState_3 == 1){
        digitalWrite(relay_3, LOW); // turn on relay 3
        toggleState_3 = 0;
      }
     else if(toggleState_4 == 1){
        digitalWrite(relay_4, LOW); // turn on relay 4
        toggleState_4 = 0;
      }
  }
    
    if (temperature >= maxTemp){
      if(toggleState_1 == 0){
        digitalWrite(relay_1, HIGH); // turn on relay 1
        toggleState_1 = 1;
      }
      else if(toggleState_2 == 0){
        digitalWrite(relay_2, HIGH); // turn on relay 2
        toggleState_2 = 1;
      }
  }
  else if (temperature < minTemp){
    if(toggleState_1 == 1){
        digitalWrite(relay_1, LOW); // turn on relay 1
        toggleState_1 = 0;
      }
    else if(toggleState_2 == 1){
        digitalWrite(relay_2, LOW); // turn on relay 1
        toggleState_2 = 0;
      }
    }
   }
  }
}