⛅ Complete Weather Station - Monitor Temperature & Humidity

📋 Why Weather Monitoring Matters for Your Farm

Weather conditions directly affect crop health, disease risk, and irrigation needs. With this weather station, you can:

🛠️ Components You'll Need

🔌 Wiring Diagram

DHT22 Sensor → ESP32
┌─────────────────────────────────┐
│ Pin 1 (VCC)  → 3.3V             │
│ Pin 2 (DATA) → GPIO16           │
│ Pin 3 (NC)   → Not connected    │
│ Pin 4 (GND)  → GND              │
└─────────────────────────────────┘

Add a 10kΩ resistor between DATA and VCC!

📖 Complete Code with Line-by-Line Explanation

/*
 * Complete Weather Station for ESP32
 * Monitors temperature and humidity using DHT22
 * Sends data to OceanRemote cloud every 5 minutes
 * Perfect for monitoring greenhouse or field conditions
 * 
 * Components Required:
 * - ESP32 board
 * - DHT22 temperature/humidity sensor
 * - 10kΩ resistor
 * - (Optional) Solar panel + battery for off-grid
 */

#include        // For internet connectivity
#include  // For sending data to cloud
#include         // DHT sensor library

// ========== DHT22 CONFIGURATION ==========
#define DHTPIN 16       // GPIO16 - Data pin for DHT22
#define DHTTYPE DHT22   // Using DHT22 sensor (more accurate than DHT11)

// ========== WIFI CONFIGURATION ==========
const char* ssid = "YOUR_WIFI";        // Replace with your WiFi name
const char* password = "YOUR_PASSWORD"; // Replace with your WiFi password

// ========== OCEANREMOTE CONFIGURATION ==========
const char* token = "YOUR_TOKEN";      // Replace with your OceanRemote device token

// Create DHT object
DHT dht(DHTPIN, DHTTYPE);

void setup() {
    // ---------- STEP 1: INITIALIZE SENSORS ----------
    Serial.begin(115200);
    dht.begin();  // Start the DHT22 sensor
    
    // ---------- STEP 2: CONNECT TO WIFI ----------
    WiFi.begin(ssid, password);
    while (WiFi.status() != WL_CONNECTED) {
        delay(500);
        Serial.print(".");
    }
    Serial.println("\n✅ WiFi connected!");
    
    // ---------- STEP 3: READ SENSOR DATA ----------
    float temp = dht.readTemperature();  // Read temperature in Celsius
    float hum = dht.readHumidity();       // Read humidity percentage
    
    // Check if readings are valid (not NaN - Not a Number)
    if (!isnan(temp) && !isnan(hum)) {
        Serial.print("🌡️ Temperature: ");
        Serial.print(temp);
        Serial.println("°C");
        Serial.print("💧 Humidity: ");
        Serial.print(hum);
        Serial.println("%");
        
        // ---------- STEP 4: SEND DATA TO OCEANREMOTE ----------
        HTTPClient http;
        http.begin("https://api.oceanremote.net/device/state");
        http.addHeader("Content-Type", "application/x-www-form-urlencoded");
        
        // Build the data string
        String data = "token=" + String(token);
        data += "&temperature=" + String(temp);
        data += "&humidity=" + String(hum);
        
        // Send POST request
        int httpCode = http.POST(data);
        
        if (httpCode > 0) {
            Serial.println("✅ Data sent to OceanRemote!");
        } else {
            Serial.println("❌ Failed to send data");
        }
        
        http.end();  // Close connection
    } else {
        Serial.println("❌ Failed to read from DHT22 sensor!");
    }
    
    // ---------- STEP 5: DEEP SLEEP (5 MINUTES) ----------
    // Sleep for 5 minutes to save power
    // Formula: minutes * 60 * 1,000,000 microseconds
    esp_sleep_enable_timer_wakeup(5 * 60 * 1000000ULL);
    Serial.println("💤 Going to sleep for 5 minutes...");
    esp_deep_sleep_start();  // ESP32 goes to sleep here
}

void loop() {
    // This function never runs due to deep sleep
    // The ESP32 wakes up, runs setup(), then sleeps again
}
    

📊 Code Breakdown: Understanding Each Part

📡 1. DHT22 Library and Initialization

#include 
#define DHTPIN 16
#define DHTTYPE DHT22
DHT dht(DHTPIN, DHTTYPE);

• #include <DHT.h> - Includes the DHT sensor library (install via Arduino Library Manager)
• #define DHTPIN 16 - Sets the GPIO pin connected to DHT22 data
• #define DHTTYPE DHT22 - Tells the library we're using DHT22 (more accurate)
• DHT dht(DHTPIN, DHTTYPE); - Creates a DHT object for reading data
• dht.begin(); - Initializes the sensor in setup()

📡 2. Reading Temperature and Humidity

float temp = dht.readTemperature();  // Returns Celsius
float hum = dht.readHumidity();       // Returns percentage (0-100%)

• dht.readTemperature() - Returns temperature in Celsius (add true for Fahrenheit: .readTemperature(true))
• dht.readHumidity() - Returns relative humidity percentage
• ⚠️ Important: These functions return NaN (Not a Number) if reading fails. Always check with !isnan()

📡 3. Sending Data to OceanRemote

HTTPClient http;
http.begin("https://api.oceanremote.net/device/state");
http.addHeader("Content-Type", "application/x-www-form-urlencoded");

String data = "token=" + String(token);
data += "&temperature=" + String(temp);
data += "&humidity=" + String(hum);

int httpCode = http.POST(data);

• HTTPClient http; - Creates an HTTP client object
• http.begin(URL) - Specifies the OceanRemote API endpoint
• http.addHeader() - Tells the server we're sending form data
• http.POST(data) - Sends the data and returns HTTP status code (200 = success)

🔋 4. Deep Sleep for Battery Life

esp_sleep_enable_timer_wakeup(5 * 60 * 1000000ULL);
esp_deep_sleep_start();

• esp_sleep_enable_timer_wakeup() - Sets a timer to wake the ESP32
• Formula: minutes × 60 × 1,000,000 (microseconds)
• esp_deep_sleep_start() - Immediately puts ESP32 into deep sleep
• Power consumption: 2.5μA (microamps) during sleep!

🎯 Customizing Your Weather Station

Change Reading Interval

// Every 5 minutes (current)
esp_sleep_enable_timer_wakeup(5 * 60 * 1000000ULL);

// Every 1 minute (more frequent)
esp_sleep_enable_timer_wakeup(1 * 60 * 1000000ULL);

// Every 15 minutes (battery saving)
esp_sleep_enable_timer_wakeup(15 * 60 * 1000000ULL);

Use Fahrenheit Instead of Celsius

float temp = dht.readTemperature(true);  // true = Fahrenheit

Add Temperature Alerts

if (temp > 35) {
    Serial.println("⚠️ HIGH TEMPERATURE! Open greenhouse vents!");
} else if (temp < 5) {
    Serial.println("⚠️ LOW TEMPERATURE! Risk of frost!");
}

if (hum > 80) {
    Serial.println("⚠️ HIGH HUMIDITY! Risk of fungal disease!");
}

📈 DHT22 vs DHT11 Comparison

🔋 Battery Life Calculation

With a 2000mAh battery and 5-minute wake intervals:

• Wake time: 3 seconds @ 150mA = 0.125mAh per cycle
• Sleep time: 5 minutes @ 0.0025mA = 0.00021mAh per cycle
• Total per cycle: ~0.125mAh
• Cycles per day: 288
• Daily consumption: 36mAh
• 2000mAh battery lasts: 2000 ÷ 36 = 55 DAYS

🚀 Next Steps: Enhance Your Weather Station

• Add a rain sensor: Detect rainfall and adjust irrigation schedules
• Add a barometric pressure sensor (BMP280): Predict weather changes
• Add an anemometer: Measure wind speed for spray timing
• Add a light sensor (LDR): Track sunlight for photosynthesis monitoring
• Connect to a display (OLED): Show real-time readings locally