How to create WEATHER BOX USING ARDUINO using DHT22 Temperature and Humidity Sensor

main.cpp

#include "DHT.h"
#include <Wire.h>
#include <LiquidCrystal_I2C.h>

// Define button pins
#define Toggle_Up 2        
#define Maxdisplay 3         
#define Set 4 

// Define led pins
#define Led_1 5
#define Led_2 6

// Define ON/OFF Relay state
// With Relay module and connect VCC-VCC jumper as the video
// We will trigger Relay by low state
#define ON  LOW
#define OFF HIGH

// Define Relay pins, I assum these two pins will be connected to Heater and Fan
// In the video i used 220AC bulb to demo
#define Heater 8 //Relay2
#define Fan 9    //Relay1

// Define DHT pins and DHT type
#define DHTPIN A0   
#define DHTTYPE DHT22   

// Define (C) or (F) degree type
#define C_Mode true
#define F_Mode false

// Default mode is (C) degree
boolean Mode = C_Mode;

// Max degree = 30
float MaxtempC = 30;
float MaxtempF = MaxtempC * 1.8 + 32; // Convert to *F

// Min degree = 25;
float MintempC = 25;  
float MintempF = MintempC * 1.8 + 32; // Convert to *F

// Change the address to appropriate for your LCD 
LiquidCrystal_I2C lcd(0x3F, 16, 2); // I2C module address, 16 columns , 2 rows
DHT dht(DHTPIN, DHTTYPE); // Init DHT 


void Init_button() { //Init button function
    
    pinMode(Toggle_Up, INPUT_PULLUP); // Setup internal pull up resistor
    pinMode(Maxdisplay, INPUT_PULLUP);// Setup internal pull up resistor
    pinMode(Set, INPUT_PULLUP);       // Setup internal pull up resistor
}

void Init_relay(){ //Init relay function
    pinMode(Heater, OUTPUT);    // Setup output
    pinMode(Fan, OUTPUT);       // Setup output
    
    digitalWrite(Heater, OFF);  // Don't trigger
    digitalWrite(Fan, OFF);     // Don't trigger
}

void Init_led(){ //Init led function
    pinMode(Led_1, OUTPUT);   // Setup output
    pinMode(Led_2, OUTPUT);   // Setup output
    
    digitalWrite(Led_1, HIGH); // ON led 1 
    digitalWrite(Led_2, LOW);  // OFF led 2
}

float Set_Value(String str){ // This function help you adjust the value of degree
    static float ArrayofValue[4]; 
    int Test_case = 0;
    int Input_number = 0;
    int Finish_case = 4;
    float Value = 0; 
    lcd.clear();
    lcd.setCursor(0,0);
    lcd.print(str);
    lcd.setCursor(5,1);
    lcd.print("00.00");

    while(Test_case < Finish_case) {
        if (!digitalRead(Maxdisplay)){  
            while(!digitalRead(Maxdisplay));
            if (Finish_case == 4) {
                lcd.clear();
                lcd.setCursor(0,0);
                lcd.print(str);
                lcd.setCursor(5,1);
                lcd.print("000.00");
                Finish_case += 1;
                Test_case = 0;
                Input_number = 0;
                for (int i = 0; i <= 4; i++)
                  ArrayofValue[i] = 0;     
            }
            
            else if (Finish_case == 5) {
                lcd.clear();
                lcd.setCursor(0,0);
                lcd.print(str);
                lcd.setCursor(5,1);
                lcd.print("00.00");
                Finish_case -= 1;
                Test_case = 0;
                Input_number = 0;
                for (int i = 0; i <= 4; i++)
                  ArrayofValue[i] = 0;   
            }
        }
        
        if (Test_case <= Finish_case - 3){
            lcd.setCursor(Test_case + 5, 1);
            lcd.print(Input_number);
        }

        else{
            lcd.setCursor(Test_case + 6, 1);
            lcd.print(Input_number);
        }
    
        if (!digitalRead(Toggle_Up)) {
            while (!digitalRead(Toggle_Up));
            if (Input_number == 9)
                Input_number = 0;
            else 
                Input_number += 1;
        }

        else if (!digitalRead(Set)) {
            while (!digitalRead(Set));
            ArrayofValue[Test_case] = Input_number;
            Test_case += 1;
            Input_number = 0;
        } 
    }

    for (int i = 0; i <= Finish_case - 1; i++){
        if (i <= Finish_case - 3)
            Value += ArrayofValue[i] * pow(10, Finish_case - 3 - i);
        else {
            if (i == Finish_case - 2)
                Value += ArrayofValue[Finish_case - 2] / 10.0;
            else 
                Value += ArrayofValue[Finish_case - 1] / 100.0;
        }   
    }

    lcd.clear();
    lcd.print("Done!");
    delay(500);
    lcd.clear();

    return Value;
}

void Set_MaxTemp_Value(){ // This function will invoke the function Set_Value() above to adjust degree1
    if (Mode == C_Mode){
        MaxtempC = Set_Value("Set Max Temp(C): ");
        MaxtempF = MaxtempC*1.8 + 32;
    }

    else{
        MaxtempF = Set_Value("Set Max Temp(F): ");
        MaxtempC = MaxtempF*0.555 - 32;
    }
}

void Set_MinTemp_Value(){ // This function will invoke the function Set_Value() above to adjust degree1
    if (Mode == C_Mode){
        MintempC = Set_Value("Set Min Temp(C): ");
        MintempF = MintempC*1.8 + 32;
    }

    else{
        MintempF = Set_Value("Set Min Temp(F): ");
        MintempC = MintempF*0.555 - 32;
    }
}

void setup() {
  Serial.begin(9600);

  Init_relay();   // Init Relay
  Init_button();  // Init Button
  Init_led();     // Init led
  
  dht.begin();    // Init DHT
  
  lcd.init();           // Init lcd
  lcd.backlight();      // Turn on LCD's led
  lcd.clear();          // Clear LCD screen
  lcd.setCursor(0, 0);  // Start LCD at column = 0 , row = 0

}

void loop() {
    float hum = dht.readHumidity();         // Get hum
    float tempC = dht.readTemperature();    // Get C temp
    float tempF = tempC*1.8 + 32;           // Convert to F

    digitalWrite(Heater, OFF);  // Don't trigger Relay
    digitalWrite(Fan, OFF);     // Don't trigger Relay
  
    digitalWrite(Led_1, HIGH);  // ON led 1
    digitalWrite(Led_2, LOW);   // OFF led 2

    // If temp is too high or too low
    while ((tempC > MaxtempC) || (tempC < MintempC)) {
        digitalWrite(Led_1, LOW);
        digitalWrite(Led_2, HIGH);
        
        lcd.clear();
        tempC = dht.readTemperature();    

        // If temp is too high
        if (tempC > MaxtempC) {
            digitalWrite(Heater, OFF);
            digitalWrite(Fan, ON);

            lcd.setCursor(4,0);
            lcd.print("Too Hot! ");
        } 

        // If temp is too low
        else if (tempC < MintempC){  
            digitalWrite(Fan, OFF);
            digitalWrite(Heater, ON);

            lcd.setCursor(4,0);
            lcd.print("Too Cold!");
        }

        lcd.setCursor(2,1);
        lcd.print("Temp: ");
        lcd.print(tempC);
        lcd.print((char)223);
        lcd.print("C");
        
        delay(500);
        
        lcd.noBacklight();
        delay(500);
        lcd.backlight();
        delay(500);
        lcd.clear();
    }

    // If press change mode between C <-> F
    if (!digitalRead(Toggle_Up)) {
        while (!digitalRead(Toggle_Up));
        if (Mode == C_Mode)
            Mode = F_Mode;
        else Mode = C_Mode;
    }

    // If press setup Max Min temp
    else if (!digitalRead(Maxdisplay)) {
        while (!digitalRead(Maxdisplay));
        lcd.clear();

        if(Mode == C_Mode) {
            lcd.setCursor(0,0);
            lcd.print("MaxTemp:");
            lcd.print(MaxtempC);
            lcd.print((char)223);
            lcd.print("C");

            lcd.setCursor(0,1);
            lcd.print("MinTemp:");
            lcd.print(MintempC);
            lcd.print((char)223);
            lcd.print("C");
        }

        else {
            lcd.setCursor(0,0);
            lcd.print("MaxTemp:");
            lcd.print(MaxtempF);
            lcd.print((char)223);
            lcd.print("F");

            lcd.setCursor(0,1);
            lcd.print("MinTemp:");
            lcd.print(MintempF);
            lcd.print((char)223);
            lcd.print("F");
        }
        
        delay(5000);
        lcd.clear();
    }


    // If press Set
    else if(!digitalRead(Set)) {
        while (!digitalRead(Set));
        const bool Max_Mode = true;
        const bool Min_Mode = false;
        String str0 = "<=";
        String str1 = "";
        bool Mode_Set = true;
        lcd.clear();
        
        while (1){ 
            lcd.setCursor(0,0);
            lcd.print("Set Max Temp");
            lcd.setCursor(14,0);
            lcd.print(str0);
            lcd.setCursor(0,1);
            lcd.print("Set Min Temp");
            lcd.setCursor(14,1);
            lcd.print(str1);

            if(!digitalRead(Set)) {
                while (!digitalRead(Set));
                if (Mode_Set == Max_Mode)
                    Set_MaxTemp_Value();
                else 
                    Set_MinTemp_Value();
                lcd.clear();
                break;
            }
            
            if (!digitalRead(Toggle_Up)){
                while(!digitalRead(Toggle_Up));
                if (str0 == "<="){
                    str0 = "";
                    str1 = "<="; 
                    Mode_Set = Min_Mode;
                }

                else {
                    str0 = "<=";
                    str1 = "";
                    Mode_Set = Max_Mode;
                }
                lcd.clear();
            }
        }
    }

    if (Mode == C_Mode) {
        lcd.setCursor(0,0);
        lcd.print("Temp: ");
        lcd.print(tempC);
        lcd.print((char)223);
        lcd.print("C");
    }

    else {
        lcd.setCursor(0,0);
        lcd.print("Temp: ");
        lcd.print(tempF);
        lcd.print((char)223);
        lcd.print("F");
    }
    
    lcd.setCursor(0,1);
    lcd.print("Hum : ");
    lcd.print(hum);
    lcd.print("%");

}