#include 
#include 

ESP8266WiFiMulti wifiMulti;

// WiFi credentials
const char* ssid1 = "IoT_Lab";
const char* password1 = "iot12345";
const char* ssid2 = "Backup_Network";
const char* password2 = "backup123";

void setup() {
    Serial.begin(115200);
    delay(1000);
    
    Serial.println("ESP8266 WiFi Connection");
    
    // Add multiple WiFi networks
    wifiMulti.addAP(ssid1, password1);
    wifiMulti.addAP(ssid2, password2);
    
    Serial.println("Connecting to WiFi...");
    
    // Try to connect to any of the networks
    while (wifiMulti.run() != WL_CONNECTED) {
        delay(1000);
        Serial.print(".");
    }
    
    Serial.println("\nConnected successfully!");
    Serial.print("IP address: ");
    Serial.println(WiFi.localIP());
    Serial.print("Signal strength: ");
    Serial.print(WiFi.RSSI());
    Serial.println(" dBm");
}

void loop() {
    // Check WiFi connection status
    if (WiFi.status() == WL_CONNECTED) {
        // Connected - do your IoT tasks here
        digitalWrite(LED_BUILTIN, LOW);  // LED ON
        delay(1000);
        digitalWrite(LED_BUILTIN, HIGH); // LED OFF
        delay(1000);
    } else {
        // Not connected - try to reconnect
        Serial.println("WiFi disconnected. Reconnecting...");
        wifiMulti.run();
    }
}
                        

#include 
#include 

// WiFi credentials
const char* ssid = "IoT_Lab";
const char* password = "iot12345";

// MQTT Broker settings
const char* mqtt_server = "broker.hivemq.com";
const int mqtt_port = 1883;
const char* mqtt_topic = "iot/lab/temperature";

WiFiClient espClient;
PubSubClient client(espClient);

void setup_wifi() {
    delay(10);
    Serial.println("Connecting to WiFi...");
    WiFi.begin(ssid, password);
    
    while (WiFi.status() != WL_CONNECTED) {
        delay(500);
        Serial.print(".");
    }
    
    Serial.println("\nWiFi connected");
    Serial.println("IP address: " + WiFi.localIP());
}

void callback(char* topic, byte* payload, unsigned int length) {
    Serial.print("Message arrived [");
    Serial.print(topic);
    Serial.print("]: ");
    
    for (int i = 0; i < length; i++) {
        Serial.print((char)payload[i]);
    }
    Serial.println();
}

void reconnect() {
    while (!client.connected()) {
        Serial.print("Attempting MQTT connection...");
        
        // Create a random client ID
        String clientId = "ESP8266Client-";
        clientId += String(random(0xffff), HEX);
        
        if (client.connect(clientId.c_str())) {
            Serial.println("connected");
            // Subscribe to topic
            client.subscribe(mqtt_topic);
        } else {
            Serial.print("failed, rc=");
            Serial.print(client.state());
            Serial.println(" try again in 5 seconds");
            delay(5000);
        }
    }
}

void setup() {
    Serial.begin(115200);
    setup_wifi();
    client.setServer(mqtt_server, mqtt_port);
    client.setCallback(callback);
}

void loop() {
    if (!client.connected()) {
        reconnect();
    }
    client.loop();
    
    // Publish sensor data every 10 seconds
    static unsigned long lastMsg = 0;
    if (millis() - lastMsg > 10000) {
        lastMsg = millis();
        
        // Simulate temperature reading
        float temperature = 25.0 + (random(0, 100) / 10.0);
        
        String msg = "Temperature: " + String(temperature) + " C";
        client.publish(mqtt_topic, msg.c_str());
        Serial.println("Message published: " + msg);
    }
}
                        

#include 
#include "Adafruit_MQTT.h"
#include "Adafruit_MQTT_Client.h"

// WiFi credentials
#define WLAN_SSID       "IoT_Lab"
#define WLAN_PASS       "iot12345"

// Adafruit IO configuration
#define AIO_SERVER      "io.adafruit.com"
#define AIO_SERVERPORT  1883
#define AIO_USERNAME    "your_username"
#define AIO_KEY         "your_key"

WiFiClient client;
Adafruit_MQTT_Client mqtt(&client, AIO_SERVER, AIO_SERVERPORT, AIO_USERNAME, AIO_KEY);

// Setup feeds
Adafruit_MQTT_Publish temperature = Adafruit_MQTT_Publish(&mqtt, AIO_USERNAME "/feeds/temperature");
Adafruit_MQTT_Subscribe led = Adafruit_MQTT_Subscribe(&mqtt, AIO_USERNAME "/feeds/led");

void MQTT_connect();

void setup() {
    Serial.begin(115200);
    delay(10);
    
    // Connect to WiFi
    Serial.println(); Serial.println();
    Serial.print("Connecting to ");
    Serial.println(WLAN_SSID);
    
    WiFi.begin(WLAN_SSID, WLAN_PASS);
    while (WiFi.status() != WL_CONNECTED) {
        delay(500);
        Serial.print(".");
    }
    Serial.println();
    Serial.println("WiFi connected");
    
    // Setup MQTT subscription for led feed
    mqtt.subscribe(&led);
}

void loop() {
    MQTT_connect();
    
    // Read subscription
    Adafruit_MQTT_Subscribe *subscription;
    while ((subscription = mqtt.readSubscription(5000))) {
        if (subscription == &led) {
            Serial.print("Got: ");
            Serial.println((char *)led.lastread);
            // Control LED based on message
        }
    }
    
    // Publish temperature every 10 seconds
    static unsigned long lastPublish = 0;
    if (millis() - lastPublish > 10000) {
        float temp = readTemperature(); // Your sensor reading function
        
        if (! temperature.publish(temp)) {
            Serial.println("Failed to publish temperature");
        } else {
            Serial.println("Temperature published!");
        }
        lastPublish = millis();
    }
}

void MQTT_connect() {
    int8_t ret;
    
    if (mqtt.connected()) {
        return;
    }
    
    Serial.print("Connecting to MQTT... ");
    uint8_t retries = 3;
    while ((ret = mqtt.connect()) != 0) {
        Serial.println(mqtt.connectErrorString(ret));
        Serial.println("Retrying MQTT connection in 5 seconds...");
        mqtt.disconnect();
        delay(5000);
        retries--;
        if (retries == 0) {
            while (1);
        }
    }
    Serial.println("MQTT Connected!");
}